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IOP Conference Series Materials Science and Engineering
OPEN ACCESS
Use of electrospray ionization mass spectrometryfor the characterization of actinide complexes insolutionTo cite this article L Berthon et al 2010 IOP Conf Ser Mater Sci Eng 9 012059
View the article online for updates and enhancements
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This content was downloaded from IP address 5299134 on 13112021 at 1321
Use of electrospray ionization mass spectrometry for the characterization of actinide complexes in solution
L Berthon1 N Zorz 1 B Gannaz 1 S Lagrave 1 T Retegan 2 A Fermvik 2 and C Ekberg3 1 CEA DEN DRCP SCPS F-30207 Bagnols-sur-Cegraveze France 2 Nuclear Chemistry 3 Industrial Materials Recycling Department of Chemical and Biological Engineering Chalmers University SE-412 96 Gothenburg Sweden
E-mail laurenceberthonceafr
Abstract In order to understand the mechanisms involved in the extraction processes developed to separate minor actinides the ldquoligandmetallic cationrdquo complexes formed in the organic phases are characterized by electrospray ionization-mass-spectrometry (ESI-MS) This paper deals with the application of the ESI-MS technique to analyze americium complexes in organic solutions Two extractant systems are investigated 1 organic solutions of nitrogen polydentate extractants such as 66rsquo-bis(56-dialkyl-124-triazin-3-yl)-22rsquo-bipyridines (BTBPs) and 2 organic solutions composed of mixture of a malonamide and a dialkylphosphoric acid
1 Introduction Electrospray ionization mass spectrometry (ESI-MS) was introduced in the 1980rsquos by Yamashita and Fenn [1]-[2] and applied to the analyses of large organic molecules More recently ESI-MS has been shown to be an appropriate technique to characterize metal-ligand complexes in solution [3]-[8] ESI-MS is a fast and sensitive technique which allows direct and continuous introduction of liquid samples A notable difference from solution-phase methods is however that analytes must be charged and then transferred to the gas phase prior to their detection It has been demonstrated recently that no shift in equilibrium occurs during the electrospray ionization upon evaporation down to troplets size of about 1 μm [9] Though the use of this technique for solvent extraction studies remains still rare [10]-[14]
This paper deals with the application of the ESI-MS technique to analyze americium complexes in the organic phase of the solvent extraction processes developed to separate minor actinides An(III) from high level liquid waste Two extraction systems are studied 1 organic solutions of nitrogen polydentate extractants such as 66rsquo-bis(56-dialkyl-124-triazin-3-yl)-22rsquo-bipyridines (BTBPs) [15]-[20] and 2 organic solutions composed of mixtures of a malonamide and a dialkylphosphoric acid dissolved in an aliphatic diluent [21]-[23] The objectives of this work are to characterize the complexes existing in the organic phases by ESI-MS in order to understand the mechanisms involved in the extraction processes
2 Experimental
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
ccopy 2010 IOP Publishing Ltd 1
21 Extractioncomplexation conditions
211 BTBP extractants Organic solutions consisted of either 0005 M CyMe4-BTBP or 0005 M C5-BTBP dissolved in cyclohexanone nitrobenzene or octanol The organic solutions were pre-equilibrated with 1M HNO3 before the experiments The aqueous solution consisted of 87x10-4 M 241Am in 1 M HNO3 The organic and aqueous solutions were mixed together in vials for 2h at 200C in a thermostated shaking device to reach equilibrium of extraction After mixing the vials were centrifuged for 10 minutes at 6200 g and samples were taken from each phase
Aliquots of 20 μL from each phase were diluted 150th in acetonitrilewater (5050) or (8020) in the case of nitrobenzene before analysis by ESI-MS
212 DMDOHEMA-HDEHP extractants A solution containing 27x10-4 M HDEHP 53x10-4 M DMDOHEMA 24x10-3 M HNO3 and 27x10-4 M of 241Am in ethanol was prepared and diluted 13rd in acetonitrilewater (5050) before analysis by ESI-MS
22 Electrospray ionization mass spectrometry The mass spectrometric measurements were recorded in positive ionization mode using a Bruker Esquire-LC quadrupole ion trap equipped with an electrospray interface installed in a glove box (Figure 1) A syringe infusion pump (Cole Palmer) delivered the sample at 90 μLh-1 to the electrospray source Experimental conditions were positive ion mode drying gas (N2) 5 Lmin nebulizer gas 5 psi 2500C ion spray voltage of 4000V cap exit offset of 60V skimmer 1 of 30 V (lower settings would have led to a loss of sensitivity and a higher setting would have led to fragmentation of the ions coming from the complexes) skimmer 2 of constant 10 V trapdrive 50 for Am-BTBP complexes and 90 for Am-DMDOHEMA-HDEHP complexes Spectra were acquired over a mass range of mz 45-2200
a b
Figure 1 Electrosptray ionization mass spectrometer Bruker Esquire LC a before nuclearisation b after setting up in a glove box
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
2
3 Results
31 Extraction of Am(III) by nitrogen polydentate ligands The nitrogen polydentate extractants were investigated in order to separate An(III) from Ln(III) Among these extractants the BTBPs act as tetradentate ligands and show good selectivity towards trivalent actinides over lanthanides [15]-[20] Complexes formed between BTBPs and actinides and lanthanides have been investigated using various experimental approaches such as crystal structures [24]-[25] UV-visible spectrophotometry [17] and liquid-liquid extraction [16] -[20] Several different types of complexes have been discussed in the literature as being involved in the extraction of actinides and lanthanides by BTBPs in nitrate media Am3+ and Eu3+ have the possibility to coordinate up to two BTBPs each but it has been shown in solution that 11 and 12 (metalextractant) complexes are formed [16]-[20] depending on the experimental conditions (nature of the diluent extractant concentration etc)
The extraction of americium (III) from nitrate media by two BTBP molecules (26-bis(5588-tetramethyl-5678-tetrahydro-benzo-[124]triazin-3-yl)-[22rsquo]bipyridine CyMe4-BTBP and 66rsquo-bis(56-dipentyl-[124]triazin-3-yl)-[22rsquo]bipyridine C5-BTBP Figure 2) diluted in three different diluents nitrobenzene octanol and cyclohexanone was investigated by ESI-MS in positive ionization mode
NN
NN
N
NN
N NN
NN
N
NN
N
C5-BTBP CyMe4-BTBP
Figure 2 Structures of the BTBPs
An example of the typical spectra obtained for each extractant is given in Figure 3 where complexes identified with Am are shown The assignments of the americium complexes are reported in Table 1 Similar spectra for the other diluents selected are observed The resulting species of interest are for both extractants regardless of the diluent L2Am3+ and L2Am(NO3)2+ the latter being the main species
Table 1 mz ratio and assignment of Am ndash BTBP species detected in ESI-MS L represents the BTBP extractant
Based peak mz
C5-BTBP-Am CyMe4-BTBP-Am
[L2M]3+ 4767 4366
[L2M(NO3)]2+ 7460 6858
These results show that as for europium [26] americium is surrounded by two extractants both in the case of C5-BTBP and CyMe4-BTBP which agrees with previous studies carried out by liquid-liquid extraction using octanol or cylclohexanone as the diluent [16]-[19] This suggests that in octanol cyclohexanone or nitrobenzene the dominant complex is L2M(NO3)3 During the ionization process and the transfer in the gas phase this species is modified and transformed into L2M(NO3)2+
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
3
and L2M3+ to form positive ions The absence of L2M(NO3)2+ could suggest that one or two nitrate ions
are probably in the outer coordination sphere Indeed if all nitrate ions were in the inner coordination sphere a singly charged species (generally preferred in the gas phase) should be observed in the mass spectrum On the other hand the very low intensity of L2M3+ in the mass spectra could suggest that at least one nitrate is bonded to the metal ions If all nitrate ions were in the outer coordination sphere the L2M3+ ion should be the main ion detected in the mass spectra Otherwise the crystal structure of (C2-BTBP)Ln(NO3)3 shows that europium is in 10-cordinate environment it is bonded to three bidentate nitrates and a tetradentate BTBP [20] Then in (C5-BTBP)2M(NO3)3 or in (CyMe4-BTBP)2M(NO3)3 we could imagine that the metal ions should be bonded to two tetradentate BTBP ligands and one nitrate the two others nitrates should be probably in outer coordination sphere Thus the ionization of these species would lead to a formation of the main ions L2M(NO3)2+
5955
7034 74604767
mars0027d +MS
0
1
2
3
6x10Intens
400 450 500 550 600 650 700 750 mz
5354
5544
6858
mars0086d +MS
0
1
2
3
4
6x10
400 450 500 550 600 650 700 750 mz
L2Am3+
L2Am(NO3)2+
B CyMe4-BTBP
L2Am3+
L2Am(NO3)2+
A C5-BTBP
LH+
LH+
Parasite complexes formedwith Ca2+ Fe2+ Zn2+
5955
7034 74604767
mars0027d +MS
0
1
2
3
6x10Intens
400 450 500 550 600 650 700 750 mz
5354
5544
6858
mars0086d +MS
0
1
2
3
4
6x10
400 450 500 550 600 650 700 750 mz
L2Am3+
L2Am(NO3)2+
B CyMe4-BTBP
L2Am3+
L2Am(NO3)2+
A C5-BTBP
LH+
LH+
Parasite complexes formedwith Ca2+ Fe2+ Zn2+
Figure 3 Positive ESI mass spectra of organic phase of BTBP in octanol after extraction L stands for BTBP Aqueous phase 241Am 87 10-4 M in HNO3 1M Organic phase BTBP 0005 M in octanol Organic phase is diluted 150th in acetonitrilewater before analysis AC5-BTBP B CyMe4-BTBP The peak at mz =6145 6224 and 6264 (Fig A) and 5544 5624 and 5663 (Fig B) are assigned to parasite complexes formed in solution with Ca Fe and Zn due to the high complexing power of the BTBPs
32 Extraction of Am(III) by DMDOHEMA-HDEHP solution In the DIAMEX (Diamide Extraction) ndash SANEX (Selective Actinide Extraction) solvent extraction process [21]-[22] developed by the French Commissariat agrave lrsquoEnergie Atomique (CEA) the separation of the trivalent actinide ions An(III) from the trivalent lanthanide ions Ln(III) is accomplished by using a mixture of a diamide and a dialkylphosphoric acid dissolved in an appropriate aliphatic diluent The NNrsquo-dimethyl-NNrsquo-dioctylhexylethoxymalonamide (DMDOHEMA Figure 4) and the di-n-ethyl-2hexylphosphoric acid (HDEHP Figure 4) are among the possible choices for the extractant mixture Under the highly acidic conditions of the aqueous phase both An(III) and Ln(III) are co-extracted by the diamide The separationrecovery of the An(III) is then accomplished in a subsequent step where the An(III) are selectively stripped from the organic phase The extraction of Ln(III) and Am(III) either by the two extractants alone or by their mixtures in n-dodecane has recently been investigated under a variety of aqueous and organic phase conditions [14][23][27]-[28]
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
4
The extraction of Ln(III) and An(III) by mixtures of the two extractants indicates a synergism at 1M nitric acid (Figure 5) Gannaz et al interpreted the extraction data as resulting from the formation of mixed dialkyl phosphoric acid ndash malonamide species in the organic phase [23]
To investigate the possible formation of a mixed DMDOHEMA-HDEHP species the extraction of neodymium by solutions containing the mixture 03 M HDEHP and 065 M DMDOHEMA in n-dodecane was previously studied in the presence of two different aqueous solutions Nd(NO3)3 in 01 M HNO3 or in 1 M HNO3 + 2 M NaNO3 [14] The ESI-MS results showed that the species formed in the organic phases were essentially the same for the two aqueous phases used to extract Nd3+ Two types of species were observed Nd-DMDOHEMA and mixed Nd-DMDOHEMA-HDEHP species
N
O
N
O
O
P OHO O
O
DMDOHEMA HDEHP
Figure 4 Structures of the DMDOHEMA and HDEHP
00001
001
1
100
10000
001 01 1 10[HNO3]aqeq (M)
DAmHDEHP 03M DMDOHEMA 07M
DMDOHEMA 07M+ HDEHP 03M
00001
001
1
100
10000
001 01 1 10[HNO3]aqeq (M)
DAmHDEHP 03M DMDOHEMA 07M
DMDOHEMA 07M+ HDEHP 03M
Figure 5 Americium extraction (DAm) vs aqueous nitric acid concentration Organic phases red 03M HDEHP in dodecane blue 07 M DMDOHEMA in dodecane black 07 M DMDOHEMA + 03 M HDEHP in n-dodecane
To pursue this study Am(III) complexes formed with the mixture HDEHP-DMDOHEMA were
investigated by ESI-MS However in order to analyze metal-ligand complexes by ESI-MS their relative concentrations in solution must be sufficient (ie gt 1 of the total ligand concentration) Otherwise the decrease of the ligand concentration leads to a decrease of the distribution ratio and subsequently to a decrease of the complex proportion in the organic phase To avoid the handling of concentrated americium solutions and to get information about Am complexes experiments were performed in homogeneous phase Solutions containing HDEHP DMDOHEMA HNO3 and 241Am in ethanol were prepared and analyzed by ESI-MS The mass spectra show as for Nd extraction the presence of DMDOHEMA-Am and mixed DMDOHEMA-HDEHP-Am complexes (Figure 6) The assignment of the species is reported in Table 2 where D stands for the malonamide and A for the anion of the organophosphoric acid respectively
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
5
As for Ln extraction mixed Am-HDEHP-DMDOHEMA complexes are observed From MS data the complexes formed can be written as DyAmA2(NO3) or DyAmA3 (with y le 5) for the mixed complexes Thus Am and Ln complexes seem to have the same stoichiometry which is consistent with liquid-liquid extraction data [23]
4836
6342
7638
8758
10051
11068
13302
600 800 1000 1200 1400 1600 mz00
05
10
15
6x10Intens
D3Am3+
D4Am3+
D2AAm2+
D2Am(NO3)2+
D3Am(NO3)2+
D3AAm2+
D2AAm(NO3)+
DA2Am+
LH+ D=DMDOHEMAA-=DEHP-
4836
6342
7638
8758
10051
11068
13302
600 800 1000 1200 1400 1600 mz00
05
10
15
6x10Intens
D3Am3+
D4Am3+
D2AAm2+
D2Am(NO3)2+
D3Am(NO3)2+
D3AAm2+
D2AAm(NO3)+
DA2Am+
LH+ D=DMDOHEMAA-=DEHP-
Figure 6 Positive ESI mass spectrum of solution containing 5310-4 M DMDOHEMA 2710-4 M HDEHP 24 10-3 M HNO3 and 2710-4 M of 241Am in ethanol D and A represent DMDOHEMA and DEHP- respectively
Table 2 mz ratio and species assignment in the positive ESI-MS data for the HDEHP-DMDOHEMA -Am3+ system in ethanol (D stands for DMDOHEMA and HA for HDEHP)
Species Base peak mz
[D3Am]3+ 5633 [D4Am]3+ 7241 [D5Am]3+ 8842
[D2Am(NO3)]2+ 6342 [D3Am(NO3)]2+ 8758 [D2Am(NO3)2]+ 13302
[D2AmA]2+ 7638 [D3AmA]2+ 10051 [DAmA2]+ 13661
[DAmA(NO3)]+ 11068 [D2AmA(NO3)]+ 15884
[D2AmA2]+ 18479
4 Conclusion Electrospray ionization - mass spectrometry was used to investigate actinide complexes in organic solutions of the solvent extraction processes ESI-MS is a valuable approach for obtaining structural information about the complexes formed during solvent extraction experiments and can give information about the stability of the complexes in gas phase
In the studied system the predominant species in gas phase are consistent with the complexes observed by other techniques in solution Nevertheless although some features of the solution
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
6
structure may be preserved by the gas-phase ions such as complex stoichiometry the nature of the coordination in the gas phase species lsquoinnerrsquo vs lsquoouterrsquo may be different than in the solution species and rearrangement may occur between the solution and bare gas ion species Thus the correlation between gas phase ions and solution phase species is a topic of ongoing research
Acknowledgments This work was carried out with the financial support of ACTINET under the Joint Research Project JRP 06-15
References [1] Yamashita M and Fenn J B 1984 J Phys Chem 88 4451-4459 [2] Yamashita M and Fenn J B 1984 J Phys Chem 88 4671-4675 [3] Daniel J M Friess S D Rajagopalan S Wendt S and Zenobi R 2000 Int J Mass Spectrom 216
1-27 [4] Di Marco V B and Bombi G G 2006 Mass Spectr Rev 25 347-379 [5] Krabbe J G A de Boer R Van der Zwan G and Lingeman H 2007 J Am Soc Mass Spectrom
18 707-713 [6] Colette S Amekraz B Madic C Berthon L Cote G and Moulin C 2002 Inorg Chem 41 7031-
7041 [7] Colette S Amekraz B Madic C Berthon L Cote G and Moulin C 2003 Inorg Chem 42 2215-
2226 [8] Crowe M C Kapoor R N Cervantes-Lee F Parkanyi L Schulte L Pannell K H and Brodbelt J
S 2005 Inorg Chem 44 6415-6424 [9] Wortmann A Kisthler-Momotova A Zenobi R Heine M C Wilhelm O and Pratsinis S E 2007
J Am Soc Mass Spectrom 18 385-393 [10] Lamouroux C Moulin C Tabet J C and Jankowski C K 2000 Rapid Commun Mass Spectrom
14 1869-1877 [11] Belair S Lamouroux C Tabarant M Labet A Mariet C and Dannus P 2004 Solvent Extr Ion
Exch 22(5) 791-811 [12] Lamouroux C Rateau S and Moulin C 2006 Rapid Commun Mass Spectrom 20 2041-2052 [13] Leclerc E Guillaumont D Guilbaud P and Berthon L 2008 Radiochim Acta 96 85-92 [14] Antonio M R Chiarizia R Gannaz B Berthon L Zorz N Hill C and Cote G 2008 Sep Sci
Technol 43 2572-2605 [15] Ekberg C Fermvik A Retegan T Skarnemark G Foreman M R S Hudson M J Englund S and
Nilsson M 2008 Radiochim Acta 96 225-233 [16] Foreman M R S J Hudson M J Geist A Madic C and Weigl M 2005 Solvent Extr Ion Exch
23 (5) 645-662 [17] Nilsson M Ekberg C Foreman M R S Hudson M J Liljenzin J O Modolo G and Skarnemark
G 2006 Solv Extr Ion Exch 24 (6) 823-843 [18] Geist A Hill C Modolo G Foreman M R S J Weigl M Gompper K and Hudson M J 2006
Solvent Extr Ion Exch 24 (4) 463-483 [19] Retegan T Ekberg C Dubois I Fermvik A Johnsson Wass T and Skarnemark G 2007 Solvent
Extr Ion Exch 25( 4) 417-431 [20] Nilsson M Andersson S Drouet F Ekberg C Foreman M Hudson M Liljenzin J O
Magnusson D and Skarnemark G 2006 Solvent Extr Ion Exch 24(3) 299-318 [21] Heacuteregraves X Nicol C Bisel I Baron P and Ramain L 1999 Proceedings of the International
Conference on Future Nuclear Systems Globalrsquo99 Nuclear Technology - Bridging the Millennia Jackson Hole WY USA p585-591
[22] Baron P Heacuteregraves X Lecomte M and Masson M 2001 Proceedings of International Conference on Back-End of the Fuel Cycle From Research to Solutions (Global 2001) Paris France
[23] Gannaz B Chiarizia R Antonio M R Hill C and Cote G 2007 Solvent Extr Ion Exch 25 313-
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
7
337 [24] Foreman M R S Hudson M J Drew M G B Hill C and Madic C 2006 Dalton Trans 1645-1653 [25] Drew M G B Foreman M R S J Hill C Hudson M J and Madic C 2005 Inorg Chem Commun
8 (3) 239-241 [26] Retegan T Berthon L Ekberg C Fermvik A Skarnemark G and Zorz N (Accepted for
publication in Solv Extr Ion Exch) [27] Gannaz B 2007 CEA Report R6159 [28] Gannaz B Antonio M R Chiarizia R Hill C and Cote G 2007 Dalton Trans 4553-4562
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
8
Use of electrospray ionization mass spectrometry for the characterization of actinide complexes in solution
L Berthon1 N Zorz 1 B Gannaz 1 S Lagrave 1 T Retegan 2 A Fermvik 2 and C Ekberg3 1 CEA DEN DRCP SCPS F-30207 Bagnols-sur-Cegraveze France 2 Nuclear Chemistry 3 Industrial Materials Recycling Department of Chemical and Biological Engineering Chalmers University SE-412 96 Gothenburg Sweden
E-mail laurenceberthonceafr
Abstract In order to understand the mechanisms involved in the extraction processes developed to separate minor actinides the ldquoligandmetallic cationrdquo complexes formed in the organic phases are characterized by electrospray ionization-mass-spectrometry (ESI-MS) This paper deals with the application of the ESI-MS technique to analyze americium complexes in organic solutions Two extractant systems are investigated 1 organic solutions of nitrogen polydentate extractants such as 66rsquo-bis(56-dialkyl-124-triazin-3-yl)-22rsquo-bipyridines (BTBPs) and 2 organic solutions composed of mixture of a malonamide and a dialkylphosphoric acid
1 Introduction Electrospray ionization mass spectrometry (ESI-MS) was introduced in the 1980rsquos by Yamashita and Fenn [1]-[2] and applied to the analyses of large organic molecules More recently ESI-MS has been shown to be an appropriate technique to characterize metal-ligand complexes in solution [3]-[8] ESI-MS is a fast and sensitive technique which allows direct and continuous introduction of liquid samples A notable difference from solution-phase methods is however that analytes must be charged and then transferred to the gas phase prior to their detection It has been demonstrated recently that no shift in equilibrium occurs during the electrospray ionization upon evaporation down to troplets size of about 1 μm [9] Though the use of this technique for solvent extraction studies remains still rare [10]-[14]
This paper deals with the application of the ESI-MS technique to analyze americium complexes in the organic phase of the solvent extraction processes developed to separate minor actinides An(III) from high level liquid waste Two extraction systems are studied 1 organic solutions of nitrogen polydentate extractants such as 66rsquo-bis(56-dialkyl-124-triazin-3-yl)-22rsquo-bipyridines (BTBPs) [15]-[20] and 2 organic solutions composed of mixtures of a malonamide and a dialkylphosphoric acid dissolved in an aliphatic diluent [21]-[23] The objectives of this work are to characterize the complexes existing in the organic phases by ESI-MS in order to understand the mechanisms involved in the extraction processes
2 Experimental
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
ccopy 2010 IOP Publishing Ltd 1
21 Extractioncomplexation conditions
211 BTBP extractants Organic solutions consisted of either 0005 M CyMe4-BTBP or 0005 M C5-BTBP dissolved in cyclohexanone nitrobenzene or octanol The organic solutions were pre-equilibrated with 1M HNO3 before the experiments The aqueous solution consisted of 87x10-4 M 241Am in 1 M HNO3 The organic and aqueous solutions were mixed together in vials for 2h at 200C in a thermostated shaking device to reach equilibrium of extraction After mixing the vials were centrifuged for 10 minutes at 6200 g and samples were taken from each phase
Aliquots of 20 μL from each phase were diluted 150th in acetonitrilewater (5050) or (8020) in the case of nitrobenzene before analysis by ESI-MS
212 DMDOHEMA-HDEHP extractants A solution containing 27x10-4 M HDEHP 53x10-4 M DMDOHEMA 24x10-3 M HNO3 and 27x10-4 M of 241Am in ethanol was prepared and diluted 13rd in acetonitrilewater (5050) before analysis by ESI-MS
22 Electrospray ionization mass spectrometry The mass spectrometric measurements were recorded in positive ionization mode using a Bruker Esquire-LC quadrupole ion trap equipped with an electrospray interface installed in a glove box (Figure 1) A syringe infusion pump (Cole Palmer) delivered the sample at 90 μLh-1 to the electrospray source Experimental conditions were positive ion mode drying gas (N2) 5 Lmin nebulizer gas 5 psi 2500C ion spray voltage of 4000V cap exit offset of 60V skimmer 1 of 30 V (lower settings would have led to a loss of sensitivity and a higher setting would have led to fragmentation of the ions coming from the complexes) skimmer 2 of constant 10 V trapdrive 50 for Am-BTBP complexes and 90 for Am-DMDOHEMA-HDEHP complexes Spectra were acquired over a mass range of mz 45-2200
a b
Figure 1 Electrosptray ionization mass spectrometer Bruker Esquire LC a before nuclearisation b after setting up in a glove box
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
2
3 Results
31 Extraction of Am(III) by nitrogen polydentate ligands The nitrogen polydentate extractants were investigated in order to separate An(III) from Ln(III) Among these extractants the BTBPs act as tetradentate ligands and show good selectivity towards trivalent actinides over lanthanides [15]-[20] Complexes formed between BTBPs and actinides and lanthanides have been investigated using various experimental approaches such as crystal structures [24]-[25] UV-visible spectrophotometry [17] and liquid-liquid extraction [16] -[20] Several different types of complexes have been discussed in the literature as being involved in the extraction of actinides and lanthanides by BTBPs in nitrate media Am3+ and Eu3+ have the possibility to coordinate up to two BTBPs each but it has been shown in solution that 11 and 12 (metalextractant) complexes are formed [16]-[20] depending on the experimental conditions (nature of the diluent extractant concentration etc)
The extraction of americium (III) from nitrate media by two BTBP molecules (26-bis(5588-tetramethyl-5678-tetrahydro-benzo-[124]triazin-3-yl)-[22rsquo]bipyridine CyMe4-BTBP and 66rsquo-bis(56-dipentyl-[124]triazin-3-yl)-[22rsquo]bipyridine C5-BTBP Figure 2) diluted in three different diluents nitrobenzene octanol and cyclohexanone was investigated by ESI-MS in positive ionization mode
NN
NN
N
NN
N NN
NN
N
NN
N
C5-BTBP CyMe4-BTBP
Figure 2 Structures of the BTBPs
An example of the typical spectra obtained for each extractant is given in Figure 3 where complexes identified with Am are shown The assignments of the americium complexes are reported in Table 1 Similar spectra for the other diluents selected are observed The resulting species of interest are for both extractants regardless of the diluent L2Am3+ and L2Am(NO3)2+ the latter being the main species
Table 1 mz ratio and assignment of Am ndash BTBP species detected in ESI-MS L represents the BTBP extractant
Based peak mz
C5-BTBP-Am CyMe4-BTBP-Am
[L2M]3+ 4767 4366
[L2M(NO3)]2+ 7460 6858
These results show that as for europium [26] americium is surrounded by two extractants both in the case of C5-BTBP and CyMe4-BTBP which agrees with previous studies carried out by liquid-liquid extraction using octanol or cylclohexanone as the diluent [16]-[19] This suggests that in octanol cyclohexanone or nitrobenzene the dominant complex is L2M(NO3)3 During the ionization process and the transfer in the gas phase this species is modified and transformed into L2M(NO3)2+
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
3
and L2M3+ to form positive ions The absence of L2M(NO3)2+ could suggest that one or two nitrate ions
are probably in the outer coordination sphere Indeed if all nitrate ions were in the inner coordination sphere a singly charged species (generally preferred in the gas phase) should be observed in the mass spectrum On the other hand the very low intensity of L2M3+ in the mass spectra could suggest that at least one nitrate is bonded to the metal ions If all nitrate ions were in the outer coordination sphere the L2M3+ ion should be the main ion detected in the mass spectra Otherwise the crystal structure of (C2-BTBP)Ln(NO3)3 shows that europium is in 10-cordinate environment it is bonded to three bidentate nitrates and a tetradentate BTBP [20] Then in (C5-BTBP)2M(NO3)3 or in (CyMe4-BTBP)2M(NO3)3 we could imagine that the metal ions should be bonded to two tetradentate BTBP ligands and one nitrate the two others nitrates should be probably in outer coordination sphere Thus the ionization of these species would lead to a formation of the main ions L2M(NO3)2+
5955
7034 74604767
mars0027d +MS
0
1
2
3
6x10Intens
400 450 500 550 600 650 700 750 mz
5354
5544
6858
mars0086d +MS
0
1
2
3
4
6x10
400 450 500 550 600 650 700 750 mz
L2Am3+
L2Am(NO3)2+
B CyMe4-BTBP
L2Am3+
L2Am(NO3)2+
A C5-BTBP
LH+
LH+
Parasite complexes formedwith Ca2+ Fe2+ Zn2+
5955
7034 74604767
mars0027d +MS
0
1
2
3
6x10Intens
400 450 500 550 600 650 700 750 mz
5354
5544
6858
mars0086d +MS
0
1
2
3
4
6x10
400 450 500 550 600 650 700 750 mz
L2Am3+
L2Am(NO3)2+
B CyMe4-BTBP
L2Am3+
L2Am(NO3)2+
A C5-BTBP
LH+
LH+
Parasite complexes formedwith Ca2+ Fe2+ Zn2+
Figure 3 Positive ESI mass spectra of organic phase of BTBP in octanol after extraction L stands for BTBP Aqueous phase 241Am 87 10-4 M in HNO3 1M Organic phase BTBP 0005 M in octanol Organic phase is diluted 150th in acetonitrilewater before analysis AC5-BTBP B CyMe4-BTBP The peak at mz =6145 6224 and 6264 (Fig A) and 5544 5624 and 5663 (Fig B) are assigned to parasite complexes formed in solution with Ca Fe and Zn due to the high complexing power of the BTBPs
32 Extraction of Am(III) by DMDOHEMA-HDEHP solution In the DIAMEX (Diamide Extraction) ndash SANEX (Selective Actinide Extraction) solvent extraction process [21]-[22] developed by the French Commissariat agrave lrsquoEnergie Atomique (CEA) the separation of the trivalent actinide ions An(III) from the trivalent lanthanide ions Ln(III) is accomplished by using a mixture of a diamide and a dialkylphosphoric acid dissolved in an appropriate aliphatic diluent The NNrsquo-dimethyl-NNrsquo-dioctylhexylethoxymalonamide (DMDOHEMA Figure 4) and the di-n-ethyl-2hexylphosphoric acid (HDEHP Figure 4) are among the possible choices for the extractant mixture Under the highly acidic conditions of the aqueous phase both An(III) and Ln(III) are co-extracted by the diamide The separationrecovery of the An(III) is then accomplished in a subsequent step where the An(III) are selectively stripped from the organic phase The extraction of Ln(III) and Am(III) either by the two extractants alone or by their mixtures in n-dodecane has recently been investigated under a variety of aqueous and organic phase conditions [14][23][27]-[28]
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
4
The extraction of Ln(III) and An(III) by mixtures of the two extractants indicates a synergism at 1M nitric acid (Figure 5) Gannaz et al interpreted the extraction data as resulting from the formation of mixed dialkyl phosphoric acid ndash malonamide species in the organic phase [23]
To investigate the possible formation of a mixed DMDOHEMA-HDEHP species the extraction of neodymium by solutions containing the mixture 03 M HDEHP and 065 M DMDOHEMA in n-dodecane was previously studied in the presence of two different aqueous solutions Nd(NO3)3 in 01 M HNO3 or in 1 M HNO3 + 2 M NaNO3 [14] The ESI-MS results showed that the species formed in the organic phases were essentially the same for the two aqueous phases used to extract Nd3+ Two types of species were observed Nd-DMDOHEMA and mixed Nd-DMDOHEMA-HDEHP species
N
O
N
O
O
P OHO O
O
DMDOHEMA HDEHP
Figure 4 Structures of the DMDOHEMA and HDEHP
00001
001
1
100
10000
001 01 1 10[HNO3]aqeq (M)
DAmHDEHP 03M DMDOHEMA 07M
DMDOHEMA 07M+ HDEHP 03M
00001
001
1
100
10000
001 01 1 10[HNO3]aqeq (M)
DAmHDEHP 03M DMDOHEMA 07M
DMDOHEMA 07M+ HDEHP 03M
Figure 5 Americium extraction (DAm) vs aqueous nitric acid concentration Organic phases red 03M HDEHP in dodecane blue 07 M DMDOHEMA in dodecane black 07 M DMDOHEMA + 03 M HDEHP in n-dodecane
To pursue this study Am(III) complexes formed with the mixture HDEHP-DMDOHEMA were
investigated by ESI-MS However in order to analyze metal-ligand complexes by ESI-MS their relative concentrations in solution must be sufficient (ie gt 1 of the total ligand concentration) Otherwise the decrease of the ligand concentration leads to a decrease of the distribution ratio and subsequently to a decrease of the complex proportion in the organic phase To avoid the handling of concentrated americium solutions and to get information about Am complexes experiments were performed in homogeneous phase Solutions containing HDEHP DMDOHEMA HNO3 and 241Am in ethanol were prepared and analyzed by ESI-MS The mass spectra show as for Nd extraction the presence of DMDOHEMA-Am and mixed DMDOHEMA-HDEHP-Am complexes (Figure 6) The assignment of the species is reported in Table 2 where D stands for the malonamide and A for the anion of the organophosphoric acid respectively
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
5
As for Ln extraction mixed Am-HDEHP-DMDOHEMA complexes are observed From MS data the complexes formed can be written as DyAmA2(NO3) or DyAmA3 (with y le 5) for the mixed complexes Thus Am and Ln complexes seem to have the same stoichiometry which is consistent with liquid-liquid extraction data [23]
4836
6342
7638
8758
10051
11068
13302
600 800 1000 1200 1400 1600 mz00
05
10
15
6x10Intens
D3Am3+
D4Am3+
D2AAm2+
D2Am(NO3)2+
D3Am(NO3)2+
D3AAm2+
D2AAm(NO3)+
DA2Am+
LH+ D=DMDOHEMAA-=DEHP-
4836
6342
7638
8758
10051
11068
13302
600 800 1000 1200 1400 1600 mz00
05
10
15
6x10Intens
D3Am3+
D4Am3+
D2AAm2+
D2Am(NO3)2+
D3Am(NO3)2+
D3AAm2+
D2AAm(NO3)+
DA2Am+
LH+ D=DMDOHEMAA-=DEHP-
Figure 6 Positive ESI mass spectrum of solution containing 5310-4 M DMDOHEMA 2710-4 M HDEHP 24 10-3 M HNO3 and 2710-4 M of 241Am in ethanol D and A represent DMDOHEMA and DEHP- respectively
Table 2 mz ratio and species assignment in the positive ESI-MS data for the HDEHP-DMDOHEMA -Am3+ system in ethanol (D stands for DMDOHEMA and HA for HDEHP)
Species Base peak mz
[D3Am]3+ 5633 [D4Am]3+ 7241 [D5Am]3+ 8842
[D2Am(NO3)]2+ 6342 [D3Am(NO3)]2+ 8758 [D2Am(NO3)2]+ 13302
[D2AmA]2+ 7638 [D3AmA]2+ 10051 [DAmA2]+ 13661
[DAmA(NO3)]+ 11068 [D2AmA(NO3)]+ 15884
[D2AmA2]+ 18479
4 Conclusion Electrospray ionization - mass spectrometry was used to investigate actinide complexes in organic solutions of the solvent extraction processes ESI-MS is a valuable approach for obtaining structural information about the complexes formed during solvent extraction experiments and can give information about the stability of the complexes in gas phase
In the studied system the predominant species in gas phase are consistent with the complexes observed by other techniques in solution Nevertheless although some features of the solution
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
6
structure may be preserved by the gas-phase ions such as complex stoichiometry the nature of the coordination in the gas phase species lsquoinnerrsquo vs lsquoouterrsquo may be different than in the solution species and rearrangement may occur between the solution and bare gas ion species Thus the correlation between gas phase ions and solution phase species is a topic of ongoing research
Acknowledgments This work was carried out with the financial support of ACTINET under the Joint Research Project JRP 06-15
References [1] Yamashita M and Fenn J B 1984 J Phys Chem 88 4451-4459 [2] Yamashita M and Fenn J B 1984 J Phys Chem 88 4671-4675 [3] Daniel J M Friess S D Rajagopalan S Wendt S and Zenobi R 2000 Int J Mass Spectrom 216
1-27 [4] Di Marco V B and Bombi G G 2006 Mass Spectr Rev 25 347-379 [5] Krabbe J G A de Boer R Van der Zwan G and Lingeman H 2007 J Am Soc Mass Spectrom
18 707-713 [6] Colette S Amekraz B Madic C Berthon L Cote G and Moulin C 2002 Inorg Chem 41 7031-
7041 [7] Colette S Amekraz B Madic C Berthon L Cote G and Moulin C 2003 Inorg Chem 42 2215-
2226 [8] Crowe M C Kapoor R N Cervantes-Lee F Parkanyi L Schulte L Pannell K H and Brodbelt J
S 2005 Inorg Chem 44 6415-6424 [9] Wortmann A Kisthler-Momotova A Zenobi R Heine M C Wilhelm O and Pratsinis S E 2007
J Am Soc Mass Spectrom 18 385-393 [10] Lamouroux C Moulin C Tabet J C and Jankowski C K 2000 Rapid Commun Mass Spectrom
14 1869-1877 [11] Belair S Lamouroux C Tabarant M Labet A Mariet C and Dannus P 2004 Solvent Extr Ion
Exch 22(5) 791-811 [12] Lamouroux C Rateau S and Moulin C 2006 Rapid Commun Mass Spectrom 20 2041-2052 [13] Leclerc E Guillaumont D Guilbaud P and Berthon L 2008 Radiochim Acta 96 85-92 [14] Antonio M R Chiarizia R Gannaz B Berthon L Zorz N Hill C and Cote G 2008 Sep Sci
Technol 43 2572-2605 [15] Ekberg C Fermvik A Retegan T Skarnemark G Foreman M R S Hudson M J Englund S and
Nilsson M 2008 Radiochim Acta 96 225-233 [16] Foreman M R S J Hudson M J Geist A Madic C and Weigl M 2005 Solvent Extr Ion Exch
23 (5) 645-662 [17] Nilsson M Ekberg C Foreman M R S Hudson M J Liljenzin J O Modolo G and Skarnemark
G 2006 Solv Extr Ion Exch 24 (6) 823-843 [18] Geist A Hill C Modolo G Foreman M R S J Weigl M Gompper K and Hudson M J 2006
Solvent Extr Ion Exch 24 (4) 463-483 [19] Retegan T Ekberg C Dubois I Fermvik A Johnsson Wass T and Skarnemark G 2007 Solvent
Extr Ion Exch 25( 4) 417-431 [20] Nilsson M Andersson S Drouet F Ekberg C Foreman M Hudson M Liljenzin J O
Magnusson D and Skarnemark G 2006 Solvent Extr Ion Exch 24(3) 299-318 [21] Heacuteregraves X Nicol C Bisel I Baron P and Ramain L 1999 Proceedings of the International
Conference on Future Nuclear Systems Globalrsquo99 Nuclear Technology - Bridging the Millennia Jackson Hole WY USA p585-591
[22] Baron P Heacuteregraves X Lecomte M and Masson M 2001 Proceedings of International Conference on Back-End of the Fuel Cycle From Research to Solutions (Global 2001) Paris France
[23] Gannaz B Chiarizia R Antonio M R Hill C and Cote G 2007 Solvent Extr Ion Exch 25 313-
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
7
337 [24] Foreman M R S Hudson M J Drew M G B Hill C and Madic C 2006 Dalton Trans 1645-1653 [25] Drew M G B Foreman M R S J Hill C Hudson M J and Madic C 2005 Inorg Chem Commun
8 (3) 239-241 [26] Retegan T Berthon L Ekberg C Fermvik A Skarnemark G and Zorz N (Accepted for
publication in Solv Extr Ion Exch) [27] Gannaz B 2007 CEA Report R6159 [28] Gannaz B Antonio M R Chiarizia R Hill C and Cote G 2007 Dalton Trans 4553-4562
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
8
21 Extractioncomplexation conditions
211 BTBP extractants Organic solutions consisted of either 0005 M CyMe4-BTBP or 0005 M C5-BTBP dissolved in cyclohexanone nitrobenzene or octanol The organic solutions were pre-equilibrated with 1M HNO3 before the experiments The aqueous solution consisted of 87x10-4 M 241Am in 1 M HNO3 The organic and aqueous solutions were mixed together in vials for 2h at 200C in a thermostated shaking device to reach equilibrium of extraction After mixing the vials were centrifuged for 10 minutes at 6200 g and samples were taken from each phase
Aliquots of 20 μL from each phase were diluted 150th in acetonitrilewater (5050) or (8020) in the case of nitrobenzene before analysis by ESI-MS
212 DMDOHEMA-HDEHP extractants A solution containing 27x10-4 M HDEHP 53x10-4 M DMDOHEMA 24x10-3 M HNO3 and 27x10-4 M of 241Am in ethanol was prepared and diluted 13rd in acetonitrilewater (5050) before analysis by ESI-MS
22 Electrospray ionization mass spectrometry The mass spectrometric measurements were recorded in positive ionization mode using a Bruker Esquire-LC quadrupole ion trap equipped with an electrospray interface installed in a glove box (Figure 1) A syringe infusion pump (Cole Palmer) delivered the sample at 90 μLh-1 to the electrospray source Experimental conditions were positive ion mode drying gas (N2) 5 Lmin nebulizer gas 5 psi 2500C ion spray voltage of 4000V cap exit offset of 60V skimmer 1 of 30 V (lower settings would have led to a loss of sensitivity and a higher setting would have led to fragmentation of the ions coming from the complexes) skimmer 2 of constant 10 V trapdrive 50 for Am-BTBP complexes and 90 for Am-DMDOHEMA-HDEHP complexes Spectra were acquired over a mass range of mz 45-2200
a b
Figure 1 Electrosptray ionization mass spectrometer Bruker Esquire LC a before nuclearisation b after setting up in a glove box
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
2
3 Results
31 Extraction of Am(III) by nitrogen polydentate ligands The nitrogen polydentate extractants were investigated in order to separate An(III) from Ln(III) Among these extractants the BTBPs act as tetradentate ligands and show good selectivity towards trivalent actinides over lanthanides [15]-[20] Complexes formed between BTBPs and actinides and lanthanides have been investigated using various experimental approaches such as crystal structures [24]-[25] UV-visible spectrophotometry [17] and liquid-liquid extraction [16] -[20] Several different types of complexes have been discussed in the literature as being involved in the extraction of actinides and lanthanides by BTBPs in nitrate media Am3+ and Eu3+ have the possibility to coordinate up to two BTBPs each but it has been shown in solution that 11 and 12 (metalextractant) complexes are formed [16]-[20] depending on the experimental conditions (nature of the diluent extractant concentration etc)
The extraction of americium (III) from nitrate media by two BTBP molecules (26-bis(5588-tetramethyl-5678-tetrahydro-benzo-[124]triazin-3-yl)-[22rsquo]bipyridine CyMe4-BTBP and 66rsquo-bis(56-dipentyl-[124]triazin-3-yl)-[22rsquo]bipyridine C5-BTBP Figure 2) diluted in three different diluents nitrobenzene octanol and cyclohexanone was investigated by ESI-MS in positive ionization mode
NN
NN
N
NN
N NN
NN
N
NN
N
C5-BTBP CyMe4-BTBP
Figure 2 Structures of the BTBPs
An example of the typical spectra obtained for each extractant is given in Figure 3 where complexes identified with Am are shown The assignments of the americium complexes are reported in Table 1 Similar spectra for the other diluents selected are observed The resulting species of interest are for both extractants regardless of the diluent L2Am3+ and L2Am(NO3)2+ the latter being the main species
Table 1 mz ratio and assignment of Am ndash BTBP species detected in ESI-MS L represents the BTBP extractant
Based peak mz
C5-BTBP-Am CyMe4-BTBP-Am
[L2M]3+ 4767 4366
[L2M(NO3)]2+ 7460 6858
These results show that as for europium [26] americium is surrounded by two extractants both in the case of C5-BTBP and CyMe4-BTBP which agrees with previous studies carried out by liquid-liquid extraction using octanol or cylclohexanone as the diluent [16]-[19] This suggests that in octanol cyclohexanone or nitrobenzene the dominant complex is L2M(NO3)3 During the ionization process and the transfer in the gas phase this species is modified and transformed into L2M(NO3)2+
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
3
and L2M3+ to form positive ions The absence of L2M(NO3)2+ could suggest that one or two nitrate ions
are probably in the outer coordination sphere Indeed if all nitrate ions were in the inner coordination sphere a singly charged species (generally preferred in the gas phase) should be observed in the mass spectrum On the other hand the very low intensity of L2M3+ in the mass spectra could suggest that at least one nitrate is bonded to the metal ions If all nitrate ions were in the outer coordination sphere the L2M3+ ion should be the main ion detected in the mass spectra Otherwise the crystal structure of (C2-BTBP)Ln(NO3)3 shows that europium is in 10-cordinate environment it is bonded to three bidentate nitrates and a tetradentate BTBP [20] Then in (C5-BTBP)2M(NO3)3 or in (CyMe4-BTBP)2M(NO3)3 we could imagine that the metal ions should be bonded to two tetradentate BTBP ligands and one nitrate the two others nitrates should be probably in outer coordination sphere Thus the ionization of these species would lead to a formation of the main ions L2M(NO3)2+
5955
7034 74604767
mars0027d +MS
0
1
2
3
6x10Intens
400 450 500 550 600 650 700 750 mz
5354
5544
6858
mars0086d +MS
0
1
2
3
4
6x10
400 450 500 550 600 650 700 750 mz
L2Am3+
L2Am(NO3)2+
B CyMe4-BTBP
L2Am3+
L2Am(NO3)2+
A C5-BTBP
LH+
LH+
Parasite complexes formedwith Ca2+ Fe2+ Zn2+
5955
7034 74604767
mars0027d +MS
0
1
2
3
6x10Intens
400 450 500 550 600 650 700 750 mz
5354
5544
6858
mars0086d +MS
0
1
2
3
4
6x10
400 450 500 550 600 650 700 750 mz
L2Am3+
L2Am(NO3)2+
B CyMe4-BTBP
L2Am3+
L2Am(NO3)2+
A C5-BTBP
LH+
LH+
Parasite complexes formedwith Ca2+ Fe2+ Zn2+
Figure 3 Positive ESI mass spectra of organic phase of BTBP in octanol after extraction L stands for BTBP Aqueous phase 241Am 87 10-4 M in HNO3 1M Organic phase BTBP 0005 M in octanol Organic phase is diluted 150th in acetonitrilewater before analysis AC5-BTBP B CyMe4-BTBP The peak at mz =6145 6224 and 6264 (Fig A) and 5544 5624 and 5663 (Fig B) are assigned to parasite complexes formed in solution with Ca Fe and Zn due to the high complexing power of the BTBPs
32 Extraction of Am(III) by DMDOHEMA-HDEHP solution In the DIAMEX (Diamide Extraction) ndash SANEX (Selective Actinide Extraction) solvent extraction process [21]-[22] developed by the French Commissariat agrave lrsquoEnergie Atomique (CEA) the separation of the trivalent actinide ions An(III) from the trivalent lanthanide ions Ln(III) is accomplished by using a mixture of a diamide and a dialkylphosphoric acid dissolved in an appropriate aliphatic diluent The NNrsquo-dimethyl-NNrsquo-dioctylhexylethoxymalonamide (DMDOHEMA Figure 4) and the di-n-ethyl-2hexylphosphoric acid (HDEHP Figure 4) are among the possible choices for the extractant mixture Under the highly acidic conditions of the aqueous phase both An(III) and Ln(III) are co-extracted by the diamide The separationrecovery of the An(III) is then accomplished in a subsequent step where the An(III) are selectively stripped from the organic phase The extraction of Ln(III) and Am(III) either by the two extractants alone or by their mixtures in n-dodecane has recently been investigated under a variety of aqueous and organic phase conditions [14][23][27]-[28]
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
4
The extraction of Ln(III) and An(III) by mixtures of the two extractants indicates a synergism at 1M nitric acid (Figure 5) Gannaz et al interpreted the extraction data as resulting from the formation of mixed dialkyl phosphoric acid ndash malonamide species in the organic phase [23]
To investigate the possible formation of a mixed DMDOHEMA-HDEHP species the extraction of neodymium by solutions containing the mixture 03 M HDEHP and 065 M DMDOHEMA in n-dodecane was previously studied in the presence of two different aqueous solutions Nd(NO3)3 in 01 M HNO3 or in 1 M HNO3 + 2 M NaNO3 [14] The ESI-MS results showed that the species formed in the organic phases were essentially the same for the two aqueous phases used to extract Nd3+ Two types of species were observed Nd-DMDOHEMA and mixed Nd-DMDOHEMA-HDEHP species
N
O
N
O
O
P OHO O
O
DMDOHEMA HDEHP
Figure 4 Structures of the DMDOHEMA and HDEHP
00001
001
1
100
10000
001 01 1 10[HNO3]aqeq (M)
DAmHDEHP 03M DMDOHEMA 07M
DMDOHEMA 07M+ HDEHP 03M
00001
001
1
100
10000
001 01 1 10[HNO3]aqeq (M)
DAmHDEHP 03M DMDOHEMA 07M
DMDOHEMA 07M+ HDEHP 03M
Figure 5 Americium extraction (DAm) vs aqueous nitric acid concentration Organic phases red 03M HDEHP in dodecane blue 07 M DMDOHEMA in dodecane black 07 M DMDOHEMA + 03 M HDEHP in n-dodecane
To pursue this study Am(III) complexes formed with the mixture HDEHP-DMDOHEMA were
investigated by ESI-MS However in order to analyze metal-ligand complexes by ESI-MS their relative concentrations in solution must be sufficient (ie gt 1 of the total ligand concentration) Otherwise the decrease of the ligand concentration leads to a decrease of the distribution ratio and subsequently to a decrease of the complex proportion in the organic phase To avoid the handling of concentrated americium solutions and to get information about Am complexes experiments were performed in homogeneous phase Solutions containing HDEHP DMDOHEMA HNO3 and 241Am in ethanol were prepared and analyzed by ESI-MS The mass spectra show as for Nd extraction the presence of DMDOHEMA-Am and mixed DMDOHEMA-HDEHP-Am complexes (Figure 6) The assignment of the species is reported in Table 2 where D stands for the malonamide and A for the anion of the organophosphoric acid respectively
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
5
As for Ln extraction mixed Am-HDEHP-DMDOHEMA complexes are observed From MS data the complexes formed can be written as DyAmA2(NO3) or DyAmA3 (with y le 5) for the mixed complexes Thus Am and Ln complexes seem to have the same stoichiometry which is consistent with liquid-liquid extraction data [23]
4836
6342
7638
8758
10051
11068
13302
600 800 1000 1200 1400 1600 mz00
05
10
15
6x10Intens
D3Am3+
D4Am3+
D2AAm2+
D2Am(NO3)2+
D3Am(NO3)2+
D3AAm2+
D2AAm(NO3)+
DA2Am+
LH+ D=DMDOHEMAA-=DEHP-
4836
6342
7638
8758
10051
11068
13302
600 800 1000 1200 1400 1600 mz00
05
10
15
6x10Intens
D3Am3+
D4Am3+
D2AAm2+
D2Am(NO3)2+
D3Am(NO3)2+
D3AAm2+
D2AAm(NO3)+
DA2Am+
LH+ D=DMDOHEMAA-=DEHP-
Figure 6 Positive ESI mass spectrum of solution containing 5310-4 M DMDOHEMA 2710-4 M HDEHP 24 10-3 M HNO3 and 2710-4 M of 241Am in ethanol D and A represent DMDOHEMA and DEHP- respectively
Table 2 mz ratio and species assignment in the positive ESI-MS data for the HDEHP-DMDOHEMA -Am3+ system in ethanol (D stands for DMDOHEMA and HA for HDEHP)
Species Base peak mz
[D3Am]3+ 5633 [D4Am]3+ 7241 [D5Am]3+ 8842
[D2Am(NO3)]2+ 6342 [D3Am(NO3)]2+ 8758 [D2Am(NO3)2]+ 13302
[D2AmA]2+ 7638 [D3AmA]2+ 10051 [DAmA2]+ 13661
[DAmA(NO3)]+ 11068 [D2AmA(NO3)]+ 15884
[D2AmA2]+ 18479
4 Conclusion Electrospray ionization - mass spectrometry was used to investigate actinide complexes in organic solutions of the solvent extraction processes ESI-MS is a valuable approach for obtaining structural information about the complexes formed during solvent extraction experiments and can give information about the stability of the complexes in gas phase
In the studied system the predominant species in gas phase are consistent with the complexes observed by other techniques in solution Nevertheless although some features of the solution
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
6
structure may be preserved by the gas-phase ions such as complex stoichiometry the nature of the coordination in the gas phase species lsquoinnerrsquo vs lsquoouterrsquo may be different than in the solution species and rearrangement may occur between the solution and bare gas ion species Thus the correlation between gas phase ions and solution phase species is a topic of ongoing research
Acknowledgments This work was carried out with the financial support of ACTINET under the Joint Research Project JRP 06-15
References [1] Yamashita M and Fenn J B 1984 J Phys Chem 88 4451-4459 [2] Yamashita M and Fenn J B 1984 J Phys Chem 88 4671-4675 [3] Daniel J M Friess S D Rajagopalan S Wendt S and Zenobi R 2000 Int J Mass Spectrom 216
1-27 [4] Di Marco V B and Bombi G G 2006 Mass Spectr Rev 25 347-379 [5] Krabbe J G A de Boer R Van der Zwan G and Lingeman H 2007 J Am Soc Mass Spectrom
18 707-713 [6] Colette S Amekraz B Madic C Berthon L Cote G and Moulin C 2002 Inorg Chem 41 7031-
7041 [7] Colette S Amekraz B Madic C Berthon L Cote G and Moulin C 2003 Inorg Chem 42 2215-
2226 [8] Crowe M C Kapoor R N Cervantes-Lee F Parkanyi L Schulte L Pannell K H and Brodbelt J
S 2005 Inorg Chem 44 6415-6424 [9] Wortmann A Kisthler-Momotova A Zenobi R Heine M C Wilhelm O and Pratsinis S E 2007
J Am Soc Mass Spectrom 18 385-393 [10] Lamouroux C Moulin C Tabet J C and Jankowski C K 2000 Rapid Commun Mass Spectrom
14 1869-1877 [11] Belair S Lamouroux C Tabarant M Labet A Mariet C and Dannus P 2004 Solvent Extr Ion
Exch 22(5) 791-811 [12] Lamouroux C Rateau S and Moulin C 2006 Rapid Commun Mass Spectrom 20 2041-2052 [13] Leclerc E Guillaumont D Guilbaud P and Berthon L 2008 Radiochim Acta 96 85-92 [14] Antonio M R Chiarizia R Gannaz B Berthon L Zorz N Hill C and Cote G 2008 Sep Sci
Technol 43 2572-2605 [15] Ekberg C Fermvik A Retegan T Skarnemark G Foreman M R S Hudson M J Englund S and
Nilsson M 2008 Radiochim Acta 96 225-233 [16] Foreman M R S J Hudson M J Geist A Madic C and Weigl M 2005 Solvent Extr Ion Exch
23 (5) 645-662 [17] Nilsson M Ekberg C Foreman M R S Hudson M J Liljenzin J O Modolo G and Skarnemark
G 2006 Solv Extr Ion Exch 24 (6) 823-843 [18] Geist A Hill C Modolo G Foreman M R S J Weigl M Gompper K and Hudson M J 2006
Solvent Extr Ion Exch 24 (4) 463-483 [19] Retegan T Ekberg C Dubois I Fermvik A Johnsson Wass T and Skarnemark G 2007 Solvent
Extr Ion Exch 25( 4) 417-431 [20] Nilsson M Andersson S Drouet F Ekberg C Foreman M Hudson M Liljenzin J O
Magnusson D and Skarnemark G 2006 Solvent Extr Ion Exch 24(3) 299-318 [21] Heacuteregraves X Nicol C Bisel I Baron P and Ramain L 1999 Proceedings of the International
Conference on Future Nuclear Systems Globalrsquo99 Nuclear Technology - Bridging the Millennia Jackson Hole WY USA p585-591
[22] Baron P Heacuteregraves X Lecomte M and Masson M 2001 Proceedings of International Conference on Back-End of the Fuel Cycle From Research to Solutions (Global 2001) Paris France
[23] Gannaz B Chiarizia R Antonio M R Hill C and Cote G 2007 Solvent Extr Ion Exch 25 313-
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
7
337 [24] Foreman M R S Hudson M J Drew M G B Hill C and Madic C 2006 Dalton Trans 1645-1653 [25] Drew M G B Foreman M R S J Hill C Hudson M J and Madic C 2005 Inorg Chem Commun
8 (3) 239-241 [26] Retegan T Berthon L Ekberg C Fermvik A Skarnemark G and Zorz N (Accepted for
publication in Solv Extr Ion Exch) [27] Gannaz B 2007 CEA Report R6159 [28] Gannaz B Antonio M R Chiarizia R Hill C and Cote G 2007 Dalton Trans 4553-4562
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
8
3 Results
31 Extraction of Am(III) by nitrogen polydentate ligands The nitrogen polydentate extractants were investigated in order to separate An(III) from Ln(III) Among these extractants the BTBPs act as tetradentate ligands and show good selectivity towards trivalent actinides over lanthanides [15]-[20] Complexes formed between BTBPs and actinides and lanthanides have been investigated using various experimental approaches such as crystal structures [24]-[25] UV-visible spectrophotometry [17] and liquid-liquid extraction [16] -[20] Several different types of complexes have been discussed in the literature as being involved in the extraction of actinides and lanthanides by BTBPs in nitrate media Am3+ and Eu3+ have the possibility to coordinate up to two BTBPs each but it has been shown in solution that 11 and 12 (metalextractant) complexes are formed [16]-[20] depending on the experimental conditions (nature of the diluent extractant concentration etc)
The extraction of americium (III) from nitrate media by two BTBP molecules (26-bis(5588-tetramethyl-5678-tetrahydro-benzo-[124]triazin-3-yl)-[22rsquo]bipyridine CyMe4-BTBP and 66rsquo-bis(56-dipentyl-[124]triazin-3-yl)-[22rsquo]bipyridine C5-BTBP Figure 2) diluted in three different diluents nitrobenzene octanol and cyclohexanone was investigated by ESI-MS in positive ionization mode
NN
NN
N
NN
N NN
NN
N
NN
N
C5-BTBP CyMe4-BTBP
Figure 2 Structures of the BTBPs
An example of the typical spectra obtained for each extractant is given in Figure 3 where complexes identified with Am are shown The assignments of the americium complexes are reported in Table 1 Similar spectra for the other diluents selected are observed The resulting species of interest are for both extractants regardless of the diluent L2Am3+ and L2Am(NO3)2+ the latter being the main species
Table 1 mz ratio and assignment of Am ndash BTBP species detected in ESI-MS L represents the BTBP extractant
Based peak mz
C5-BTBP-Am CyMe4-BTBP-Am
[L2M]3+ 4767 4366
[L2M(NO3)]2+ 7460 6858
These results show that as for europium [26] americium is surrounded by two extractants both in the case of C5-BTBP and CyMe4-BTBP which agrees with previous studies carried out by liquid-liquid extraction using octanol or cylclohexanone as the diluent [16]-[19] This suggests that in octanol cyclohexanone or nitrobenzene the dominant complex is L2M(NO3)3 During the ionization process and the transfer in the gas phase this species is modified and transformed into L2M(NO3)2+
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
3
and L2M3+ to form positive ions The absence of L2M(NO3)2+ could suggest that one or two nitrate ions
are probably in the outer coordination sphere Indeed if all nitrate ions were in the inner coordination sphere a singly charged species (generally preferred in the gas phase) should be observed in the mass spectrum On the other hand the very low intensity of L2M3+ in the mass spectra could suggest that at least one nitrate is bonded to the metal ions If all nitrate ions were in the outer coordination sphere the L2M3+ ion should be the main ion detected in the mass spectra Otherwise the crystal structure of (C2-BTBP)Ln(NO3)3 shows that europium is in 10-cordinate environment it is bonded to three bidentate nitrates and a tetradentate BTBP [20] Then in (C5-BTBP)2M(NO3)3 or in (CyMe4-BTBP)2M(NO3)3 we could imagine that the metal ions should be bonded to two tetradentate BTBP ligands and one nitrate the two others nitrates should be probably in outer coordination sphere Thus the ionization of these species would lead to a formation of the main ions L2M(NO3)2+
5955
7034 74604767
mars0027d +MS
0
1
2
3
6x10Intens
400 450 500 550 600 650 700 750 mz
5354
5544
6858
mars0086d +MS
0
1
2
3
4
6x10
400 450 500 550 600 650 700 750 mz
L2Am3+
L2Am(NO3)2+
B CyMe4-BTBP
L2Am3+
L2Am(NO3)2+
A C5-BTBP
LH+
LH+
Parasite complexes formedwith Ca2+ Fe2+ Zn2+
5955
7034 74604767
mars0027d +MS
0
1
2
3
6x10Intens
400 450 500 550 600 650 700 750 mz
5354
5544
6858
mars0086d +MS
0
1
2
3
4
6x10
400 450 500 550 600 650 700 750 mz
L2Am3+
L2Am(NO3)2+
B CyMe4-BTBP
L2Am3+
L2Am(NO3)2+
A C5-BTBP
LH+
LH+
Parasite complexes formedwith Ca2+ Fe2+ Zn2+
Figure 3 Positive ESI mass spectra of organic phase of BTBP in octanol after extraction L stands for BTBP Aqueous phase 241Am 87 10-4 M in HNO3 1M Organic phase BTBP 0005 M in octanol Organic phase is diluted 150th in acetonitrilewater before analysis AC5-BTBP B CyMe4-BTBP The peak at mz =6145 6224 and 6264 (Fig A) and 5544 5624 and 5663 (Fig B) are assigned to parasite complexes formed in solution with Ca Fe and Zn due to the high complexing power of the BTBPs
32 Extraction of Am(III) by DMDOHEMA-HDEHP solution In the DIAMEX (Diamide Extraction) ndash SANEX (Selective Actinide Extraction) solvent extraction process [21]-[22] developed by the French Commissariat agrave lrsquoEnergie Atomique (CEA) the separation of the trivalent actinide ions An(III) from the trivalent lanthanide ions Ln(III) is accomplished by using a mixture of a diamide and a dialkylphosphoric acid dissolved in an appropriate aliphatic diluent The NNrsquo-dimethyl-NNrsquo-dioctylhexylethoxymalonamide (DMDOHEMA Figure 4) and the di-n-ethyl-2hexylphosphoric acid (HDEHP Figure 4) are among the possible choices for the extractant mixture Under the highly acidic conditions of the aqueous phase both An(III) and Ln(III) are co-extracted by the diamide The separationrecovery of the An(III) is then accomplished in a subsequent step where the An(III) are selectively stripped from the organic phase The extraction of Ln(III) and Am(III) either by the two extractants alone or by their mixtures in n-dodecane has recently been investigated under a variety of aqueous and organic phase conditions [14][23][27]-[28]
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
4
The extraction of Ln(III) and An(III) by mixtures of the two extractants indicates a synergism at 1M nitric acid (Figure 5) Gannaz et al interpreted the extraction data as resulting from the formation of mixed dialkyl phosphoric acid ndash malonamide species in the organic phase [23]
To investigate the possible formation of a mixed DMDOHEMA-HDEHP species the extraction of neodymium by solutions containing the mixture 03 M HDEHP and 065 M DMDOHEMA in n-dodecane was previously studied in the presence of two different aqueous solutions Nd(NO3)3 in 01 M HNO3 or in 1 M HNO3 + 2 M NaNO3 [14] The ESI-MS results showed that the species formed in the organic phases were essentially the same for the two aqueous phases used to extract Nd3+ Two types of species were observed Nd-DMDOHEMA and mixed Nd-DMDOHEMA-HDEHP species
N
O
N
O
O
P OHO O
O
DMDOHEMA HDEHP
Figure 4 Structures of the DMDOHEMA and HDEHP
00001
001
1
100
10000
001 01 1 10[HNO3]aqeq (M)
DAmHDEHP 03M DMDOHEMA 07M
DMDOHEMA 07M+ HDEHP 03M
00001
001
1
100
10000
001 01 1 10[HNO3]aqeq (M)
DAmHDEHP 03M DMDOHEMA 07M
DMDOHEMA 07M+ HDEHP 03M
Figure 5 Americium extraction (DAm) vs aqueous nitric acid concentration Organic phases red 03M HDEHP in dodecane blue 07 M DMDOHEMA in dodecane black 07 M DMDOHEMA + 03 M HDEHP in n-dodecane
To pursue this study Am(III) complexes formed with the mixture HDEHP-DMDOHEMA were
investigated by ESI-MS However in order to analyze metal-ligand complexes by ESI-MS their relative concentrations in solution must be sufficient (ie gt 1 of the total ligand concentration) Otherwise the decrease of the ligand concentration leads to a decrease of the distribution ratio and subsequently to a decrease of the complex proportion in the organic phase To avoid the handling of concentrated americium solutions and to get information about Am complexes experiments were performed in homogeneous phase Solutions containing HDEHP DMDOHEMA HNO3 and 241Am in ethanol were prepared and analyzed by ESI-MS The mass spectra show as for Nd extraction the presence of DMDOHEMA-Am and mixed DMDOHEMA-HDEHP-Am complexes (Figure 6) The assignment of the species is reported in Table 2 where D stands for the malonamide and A for the anion of the organophosphoric acid respectively
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
5
As for Ln extraction mixed Am-HDEHP-DMDOHEMA complexes are observed From MS data the complexes formed can be written as DyAmA2(NO3) or DyAmA3 (with y le 5) for the mixed complexes Thus Am and Ln complexes seem to have the same stoichiometry which is consistent with liquid-liquid extraction data [23]
4836
6342
7638
8758
10051
11068
13302
600 800 1000 1200 1400 1600 mz00
05
10
15
6x10Intens
D3Am3+
D4Am3+
D2AAm2+
D2Am(NO3)2+
D3Am(NO3)2+
D3AAm2+
D2AAm(NO3)+
DA2Am+
LH+ D=DMDOHEMAA-=DEHP-
4836
6342
7638
8758
10051
11068
13302
600 800 1000 1200 1400 1600 mz00
05
10
15
6x10Intens
D3Am3+
D4Am3+
D2AAm2+
D2Am(NO3)2+
D3Am(NO3)2+
D3AAm2+
D2AAm(NO3)+
DA2Am+
LH+ D=DMDOHEMAA-=DEHP-
Figure 6 Positive ESI mass spectrum of solution containing 5310-4 M DMDOHEMA 2710-4 M HDEHP 24 10-3 M HNO3 and 2710-4 M of 241Am in ethanol D and A represent DMDOHEMA and DEHP- respectively
Table 2 mz ratio and species assignment in the positive ESI-MS data for the HDEHP-DMDOHEMA -Am3+ system in ethanol (D stands for DMDOHEMA and HA for HDEHP)
Species Base peak mz
[D3Am]3+ 5633 [D4Am]3+ 7241 [D5Am]3+ 8842
[D2Am(NO3)]2+ 6342 [D3Am(NO3)]2+ 8758 [D2Am(NO3)2]+ 13302
[D2AmA]2+ 7638 [D3AmA]2+ 10051 [DAmA2]+ 13661
[DAmA(NO3)]+ 11068 [D2AmA(NO3)]+ 15884
[D2AmA2]+ 18479
4 Conclusion Electrospray ionization - mass spectrometry was used to investigate actinide complexes in organic solutions of the solvent extraction processes ESI-MS is a valuable approach for obtaining structural information about the complexes formed during solvent extraction experiments and can give information about the stability of the complexes in gas phase
In the studied system the predominant species in gas phase are consistent with the complexes observed by other techniques in solution Nevertheless although some features of the solution
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
6
structure may be preserved by the gas-phase ions such as complex stoichiometry the nature of the coordination in the gas phase species lsquoinnerrsquo vs lsquoouterrsquo may be different than in the solution species and rearrangement may occur between the solution and bare gas ion species Thus the correlation between gas phase ions and solution phase species is a topic of ongoing research
Acknowledgments This work was carried out with the financial support of ACTINET under the Joint Research Project JRP 06-15
References [1] Yamashita M and Fenn J B 1984 J Phys Chem 88 4451-4459 [2] Yamashita M and Fenn J B 1984 J Phys Chem 88 4671-4675 [3] Daniel J M Friess S D Rajagopalan S Wendt S and Zenobi R 2000 Int J Mass Spectrom 216
1-27 [4] Di Marco V B and Bombi G G 2006 Mass Spectr Rev 25 347-379 [5] Krabbe J G A de Boer R Van der Zwan G and Lingeman H 2007 J Am Soc Mass Spectrom
18 707-713 [6] Colette S Amekraz B Madic C Berthon L Cote G and Moulin C 2002 Inorg Chem 41 7031-
7041 [7] Colette S Amekraz B Madic C Berthon L Cote G and Moulin C 2003 Inorg Chem 42 2215-
2226 [8] Crowe M C Kapoor R N Cervantes-Lee F Parkanyi L Schulte L Pannell K H and Brodbelt J
S 2005 Inorg Chem 44 6415-6424 [9] Wortmann A Kisthler-Momotova A Zenobi R Heine M C Wilhelm O and Pratsinis S E 2007
J Am Soc Mass Spectrom 18 385-393 [10] Lamouroux C Moulin C Tabet J C and Jankowski C K 2000 Rapid Commun Mass Spectrom
14 1869-1877 [11] Belair S Lamouroux C Tabarant M Labet A Mariet C and Dannus P 2004 Solvent Extr Ion
Exch 22(5) 791-811 [12] Lamouroux C Rateau S and Moulin C 2006 Rapid Commun Mass Spectrom 20 2041-2052 [13] Leclerc E Guillaumont D Guilbaud P and Berthon L 2008 Radiochim Acta 96 85-92 [14] Antonio M R Chiarizia R Gannaz B Berthon L Zorz N Hill C and Cote G 2008 Sep Sci
Technol 43 2572-2605 [15] Ekberg C Fermvik A Retegan T Skarnemark G Foreman M R S Hudson M J Englund S and
Nilsson M 2008 Radiochim Acta 96 225-233 [16] Foreman M R S J Hudson M J Geist A Madic C and Weigl M 2005 Solvent Extr Ion Exch
23 (5) 645-662 [17] Nilsson M Ekberg C Foreman M R S Hudson M J Liljenzin J O Modolo G and Skarnemark
G 2006 Solv Extr Ion Exch 24 (6) 823-843 [18] Geist A Hill C Modolo G Foreman M R S J Weigl M Gompper K and Hudson M J 2006
Solvent Extr Ion Exch 24 (4) 463-483 [19] Retegan T Ekberg C Dubois I Fermvik A Johnsson Wass T and Skarnemark G 2007 Solvent
Extr Ion Exch 25( 4) 417-431 [20] Nilsson M Andersson S Drouet F Ekberg C Foreman M Hudson M Liljenzin J O
Magnusson D and Skarnemark G 2006 Solvent Extr Ion Exch 24(3) 299-318 [21] Heacuteregraves X Nicol C Bisel I Baron P and Ramain L 1999 Proceedings of the International
Conference on Future Nuclear Systems Globalrsquo99 Nuclear Technology - Bridging the Millennia Jackson Hole WY USA p585-591
[22] Baron P Heacuteregraves X Lecomte M and Masson M 2001 Proceedings of International Conference on Back-End of the Fuel Cycle From Research to Solutions (Global 2001) Paris France
[23] Gannaz B Chiarizia R Antonio M R Hill C and Cote G 2007 Solvent Extr Ion Exch 25 313-
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
7
337 [24] Foreman M R S Hudson M J Drew M G B Hill C and Madic C 2006 Dalton Trans 1645-1653 [25] Drew M G B Foreman M R S J Hill C Hudson M J and Madic C 2005 Inorg Chem Commun
8 (3) 239-241 [26] Retegan T Berthon L Ekberg C Fermvik A Skarnemark G and Zorz N (Accepted for
publication in Solv Extr Ion Exch) [27] Gannaz B 2007 CEA Report R6159 [28] Gannaz B Antonio M R Chiarizia R Hill C and Cote G 2007 Dalton Trans 4553-4562
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
8
and L2M3+ to form positive ions The absence of L2M(NO3)2+ could suggest that one or two nitrate ions
are probably in the outer coordination sphere Indeed if all nitrate ions were in the inner coordination sphere a singly charged species (generally preferred in the gas phase) should be observed in the mass spectrum On the other hand the very low intensity of L2M3+ in the mass spectra could suggest that at least one nitrate is bonded to the metal ions If all nitrate ions were in the outer coordination sphere the L2M3+ ion should be the main ion detected in the mass spectra Otherwise the crystal structure of (C2-BTBP)Ln(NO3)3 shows that europium is in 10-cordinate environment it is bonded to three bidentate nitrates and a tetradentate BTBP [20] Then in (C5-BTBP)2M(NO3)3 or in (CyMe4-BTBP)2M(NO3)3 we could imagine that the metal ions should be bonded to two tetradentate BTBP ligands and one nitrate the two others nitrates should be probably in outer coordination sphere Thus the ionization of these species would lead to a formation of the main ions L2M(NO3)2+
5955
7034 74604767
mars0027d +MS
0
1
2
3
6x10Intens
400 450 500 550 600 650 700 750 mz
5354
5544
6858
mars0086d +MS
0
1
2
3
4
6x10
400 450 500 550 600 650 700 750 mz
L2Am3+
L2Am(NO3)2+
B CyMe4-BTBP
L2Am3+
L2Am(NO3)2+
A C5-BTBP
LH+
LH+
Parasite complexes formedwith Ca2+ Fe2+ Zn2+
5955
7034 74604767
mars0027d +MS
0
1
2
3
6x10Intens
400 450 500 550 600 650 700 750 mz
5354
5544
6858
mars0086d +MS
0
1
2
3
4
6x10
400 450 500 550 600 650 700 750 mz
L2Am3+
L2Am(NO3)2+
B CyMe4-BTBP
L2Am3+
L2Am(NO3)2+
A C5-BTBP
LH+
LH+
Parasite complexes formedwith Ca2+ Fe2+ Zn2+
Figure 3 Positive ESI mass spectra of organic phase of BTBP in octanol after extraction L stands for BTBP Aqueous phase 241Am 87 10-4 M in HNO3 1M Organic phase BTBP 0005 M in octanol Organic phase is diluted 150th in acetonitrilewater before analysis AC5-BTBP B CyMe4-BTBP The peak at mz =6145 6224 and 6264 (Fig A) and 5544 5624 and 5663 (Fig B) are assigned to parasite complexes formed in solution with Ca Fe and Zn due to the high complexing power of the BTBPs
32 Extraction of Am(III) by DMDOHEMA-HDEHP solution In the DIAMEX (Diamide Extraction) ndash SANEX (Selective Actinide Extraction) solvent extraction process [21]-[22] developed by the French Commissariat agrave lrsquoEnergie Atomique (CEA) the separation of the trivalent actinide ions An(III) from the trivalent lanthanide ions Ln(III) is accomplished by using a mixture of a diamide and a dialkylphosphoric acid dissolved in an appropriate aliphatic diluent The NNrsquo-dimethyl-NNrsquo-dioctylhexylethoxymalonamide (DMDOHEMA Figure 4) and the di-n-ethyl-2hexylphosphoric acid (HDEHP Figure 4) are among the possible choices for the extractant mixture Under the highly acidic conditions of the aqueous phase both An(III) and Ln(III) are co-extracted by the diamide The separationrecovery of the An(III) is then accomplished in a subsequent step where the An(III) are selectively stripped from the organic phase The extraction of Ln(III) and Am(III) either by the two extractants alone or by their mixtures in n-dodecane has recently been investigated under a variety of aqueous and organic phase conditions [14][23][27]-[28]
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
4
The extraction of Ln(III) and An(III) by mixtures of the two extractants indicates a synergism at 1M nitric acid (Figure 5) Gannaz et al interpreted the extraction data as resulting from the formation of mixed dialkyl phosphoric acid ndash malonamide species in the organic phase [23]
To investigate the possible formation of a mixed DMDOHEMA-HDEHP species the extraction of neodymium by solutions containing the mixture 03 M HDEHP and 065 M DMDOHEMA in n-dodecane was previously studied in the presence of two different aqueous solutions Nd(NO3)3 in 01 M HNO3 or in 1 M HNO3 + 2 M NaNO3 [14] The ESI-MS results showed that the species formed in the organic phases were essentially the same for the two aqueous phases used to extract Nd3+ Two types of species were observed Nd-DMDOHEMA and mixed Nd-DMDOHEMA-HDEHP species
N
O
N
O
O
P OHO O
O
DMDOHEMA HDEHP
Figure 4 Structures of the DMDOHEMA and HDEHP
00001
001
1
100
10000
001 01 1 10[HNO3]aqeq (M)
DAmHDEHP 03M DMDOHEMA 07M
DMDOHEMA 07M+ HDEHP 03M
00001
001
1
100
10000
001 01 1 10[HNO3]aqeq (M)
DAmHDEHP 03M DMDOHEMA 07M
DMDOHEMA 07M+ HDEHP 03M
Figure 5 Americium extraction (DAm) vs aqueous nitric acid concentration Organic phases red 03M HDEHP in dodecane blue 07 M DMDOHEMA in dodecane black 07 M DMDOHEMA + 03 M HDEHP in n-dodecane
To pursue this study Am(III) complexes formed with the mixture HDEHP-DMDOHEMA were
investigated by ESI-MS However in order to analyze metal-ligand complexes by ESI-MS their relative concentrations in solution must be sufficient (ie gt 1 of the total ligand concentration) Otherwise the decrease of the ligand concentration leads to a decrease of the distribution ratio and subsequently to a decrease of the complex proportion in the organic phase To avoid the handling of concentrated americium solutions and to get information about Am complexes experiments were performed in homogeneous phase Solutions containing HDEHP DMDOHEMA HNO3 and 241Am in ethanol were prepared and analyzed by ESI-MS The mass spectra show as for Nd extraction the presence of DMDOHEMA-Am and mixed DMDOHEMA-HDEHP-Am complexes (Figure 6) The assignment of the species is reported in Table 2 where D stands for the malonamide and A for the anion of the organophosphoric acid respectively
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
5
As for Ln extraction mixed Am-HDEHP-DMDOHEMA complexes are observed From MS data the complexes formed can be written as DyAmA2(NO3) or DyAmA3 (with y le 5) for the mixed complexes Thus Am and Ln complexes seem to have the same stoichiometry which is consistent with liquid-liquid extraction data [23]
4836
6342
7638
8758
10051
11068
13302
600 800 1000 1200 1400 1600 mz00
05
10
15
6x10Intens
D3Am3+
D4Am3+
D2AAm2+
D2Am(NO3)2+
D3Am(NO3)2+
D3AAm2+
D2AAm(NO3)+
DA2Am+
LH+ D=DMDOHEMAA-=DEHP-
4836
6342
7638
8758
10051
11068
13302
600 800 1000 1200 1400 1600 mz00
05
10
15
6x10Intens
D3Am3+
D4Am3+
D2AAm2+
D2Am(NO3)2+
D3Am(NO3)2+
D3AAm2+
D2AAm(NO3)+
DA2Am+
LH+ D=DMDOHEMAA-=DEHP-
Figure 6 Positive ESI mass spectrum of solution containing 5310-4 M DMDOHEMA 2710-4 M HDEHP 24 10-3 M HNO3 and 2710-4 M of 241Am in ethanol D and A represent DMDOHEMA and DEHP- respectively
Table 2 mz ratio and species assignment in the positive ESI-MS data for the HDEHP-DMDOHEMA -Am3+ system in ethanol (D stands for DMDOHEMA and HA for HDEHP)
Species Base peak mz
[D3Am]3+ 5633 [D4Am]3+ 7241 [D5Am]3+ 8842
[D2Am(NO3)]2+ 6342 [D3Am(NO3)]2+ 8758 [D2Am(NO3)2]+ 13302
[D2AmA]2+ 7638 [D3AmA]2+ 10051 [DAmA2]+ 13661
[DAmA(NO3)]+ 11068 [D2AmA(NO3)]+ 15884
[D2AmA2]+ 18479
4 Conclusion Electrospray ionization - mass spectrometry was used to investigate actinide complexes in organic solutions of the solvent extraction processes ESI-MS is a valuable approach for obtaining structural information about the complexes formed during solvent extraction experiments and can give information about the stability of the complexes in gas phase
In the studied system the predominant species in gas phase are consistent with the complexes observed by other techniques in solution Nevertheless although some features of the solution
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
6
structure may be preserved by the gas-phase ions such as complex stoichiometry the nature of the coordination in the gas phase species lsquoinnerrsquo vs lsquoouterrsquo may be different than in the solution species and rearrangement may occur between the solution and bare gas ion species Thus the correlation between gas phase ions and solution phase species is a topic of ongoing research
Acknowledgments This work was carried out with the financial support of ACTINET under the Joint Research Project JRP 06-15
References [1] Yamashita M and Fenn J B 1984 J Phys Chem 88 4451-4459 [2] Yamashita M and Fenn J B 1984 J Phys Chem 88 4671-4675 [3] Daniel J M Friess S D Rajagopalan S Wendt S and Zenobi R 2000 Int J Mass Spectrom 216
1-27 [4] Di Marco V B and Bombi G G 2006 Mass Spectr Rev 25 347-379 [5] Krabbe J G A de Boer R Van der Zwan G and Lingeman H 2007 J Am Soc Mass Spectrom
18 707-713 [6] Colette S Amekraz B Madic C Berthon L Cote G and Moulin C 2002 Inorg Chem 41 7031-
7041 [7] Colette S Amekraz B Madic C Berthon L Cote G and Moulin C 2003 Inorg Chem 42 2215-
2226 [8] Crowe M C Kapoor R N Cervantes-Lee F Parkanyi L Schulte L Pannell K H and Brodbelt J
S 2005 Inorg Chem 44 6415-6424 [9] Wortmann A Kisthler-Momotova A Zenobi R Heine M C Wilhelm O and Pratsinis S E 2007
J Am Soc Mass Spectrom 18 385-393 [10] Lamouroux C Moulin C Tabet J C and Jankowski C K 2000 Rapid Commun Mass Spectrom
14 1869-1877 [11] Belair S Lamouroux C Tabarant M Labet A Mariet C and Dannus P 2004 Solvent Extr Ion
Exch 22(5) 791-811 [12] Lamouroux C Rateau S and Moulin C 2006 Rapid Commun Mass Spectrom 20 2041-2052 [13] Leclerc E Guillaumont D Guilbaud P and Berthon L 2008 Radiochim Acta 96 85-92 [14] Antonio M R Chiarizia R Gannaz B Berthon L Zorz N Hill C and Cote G 2008 Sep Sci
Technol 43 2572-2605 [15] Ekberg C Fermvik A Retegan T Skarnemark G Foreman M R S Hudson M J Englund S and
Nilsson M 2008 Radiochim Acta 96 225-233 [16] Foreman M R S J Hudson M J Geist A Madic C and Weigl M 2005 Solvent Extr Ion Exch
23 (5) 645-662 [17] Nilsson M Ekberg C Foreman M R S Hudson M J Liljenzin J O Modolo G and Skarnemark
G 2006 Solv Extr Ion Exch 24 (6) 823-843 [18] Geist A Hill C Modolo G Foreman M R S J Weigl M Gompper K and Hudson M J 2006
Solvent Extr Ion Exch 24 (4) 463-483 [19] Retegan T Ekberg C Dubois I Fermvik A Johnsson Wass T and Skarnemark G 2007 Solvent
Extr Ion Exch 25( 4) 417-431 [20] Nilsson M Andersson S Drouet F Ekberg C Foreman M Hudson M Liljenzin J O
Magnusson D and Skarnemark G 2006 Solvent Extr Ion Exch 24(3) 299-318 [21] Heacuteregraves X Nicol C Bisel I Baron P and Ramain L 1999 Proceedings of the International
Conference on Future Nuclear Systems Globalrsquo99 Nuclear Technology - Bridging the Millennia Jackson Hole WY USA p585-591
[22] Baron P Heacuteregraves X Lecomte M and Masson M 2001 Proceedings of International Conference on Back-End of the Fuel Cycle From Research to Solutions (Global 2001) Paris France
[23] Gannaz B Chiarizia R Antonio M R Hill C and Cote G 2007 Solvent Extr Ion Exch 25 313-
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
7
337 [24] Foreman M R S Hudson M J Drew M G B Hill C and Madic C 2006 Dalton Trans 1645-1653 [25] Drew M G B Foreman M R S J Hill C Hudson M J and Madic C 2005 Inorg Chem Commun
8 (3) 239-241 [26] Retegan T Berthon L Ekberg C Fermvik A Skarnemark G and Zorz N (Accepted for
publication in Solv Extr Ion Exch) [27] Gannaz B 2007 CEA Report R6159 [28] Gannaz B Antonio M R Chiarizia R Hill C and Cote G 2007 Dalton Trans 4553-4562
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
8
The extraction of Ln(III) and An(III) by mixtures of the two extractants indicates a synergism at 1M nitric acid (Figure 5) Gannaz et al interpreted the extraction data as resulting from the formation of mixed dialkyl phosphoric acid ndash malonamide species in the organic phase [23]
To investigate the possible formation of a mixed DMDOHEMA-HDEHP species the extraction of neodymium by solutions containing the mixture 03 M HDEHP and 065 M DMDOHEMA in n-dodecane was previously studied in the presence of two different aqueous solutions Nd(NO3)3 in 01 M HNO3 or in 1 M HNO3 + 2 M NaNO3 [14] The ESI-MS results showed that the species formed in the organic phases were essentially the same for the two aqueous phases used to extract Nd3+ Two types of species were observed Nd-DMDOHEMA and mixed Nd-DMDOHEMA-HDEHP species
N
O
N
O
O
P OHO O
O
DMDOHEMA HDEHP
Figure 4 Structures of the DMDOHEMA and HDEHP
00001
001
1
100
10000
001 01 1 10[HNO3]aqeq (M)
DAmHDEHP 03M DMDOHEMA 07M
DMDOHEMA 07M+ HDEHP 03M
00001
001
1
100
10000
001 01 1 10[HNO3]aqeq (M)
DAmHDEHP 03M DMDOHEMA 07M
DMDOHEMA 07M+ HDEHP 03M
Figure 5 Americium extraction (DAm) vs aqueous nitric acid concentration Organic phases red 03M HDEHP in dodecane blue 07 M DMDOHEMA in dodecane black 07 M DMDOHEMA + 03 M HDEHP in n-dodecane
To pursue this study Am(III) complexes formed with the mixture HDEHP-DMDOHEMA were
investigated by ESI-MS However in order to analyze metal-ligand complexes by ESI-MS their relative concentrations in solution must be sufficient (ie gt 1 of the total ligand concentration) Otherwise the decrease of the ligand concentration leads to a decrease of the distribution ratio and subsequently to a decrease of the complex proportion in the organic phase To avoid the handling of concentrated americium solutions and to get information about Am complexes experiments were performed in homogeneous phase Solutions containing HDEHP DMDOHEMA HNO3 and 241Am in ethanol were prepared and analyzed by ESI-MS The mass spectra show as for Nd extraction the presence of DMDOHEMA-Am and mixed DMDOHEMA-HDEHP-Am complexes (Figure 6) The assignment of the species is reported in Table 2 where D stands for the malonamide and A for the anion of the organophosphoric acid respectively
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
5
As for Ln extraction mixed Am-HDEHP-DMDOHEMA complexes are observed From MS data the complexes formed can be written as DyAmA2(NO3) or DyAmA3 (with y le 5) for the mixed complexes Thus Am and Ln complexes seem to have the same stoichiometry which is consistent with liquid-liquid extraction data [23]
4836
6342
7638
8758
10051
11068
13302
600 800 1000 1200 1400 1600 mz00
05
10
15
6x10Intens
D3Am3+
D4Am3+
D2AAm2+
D2Am(NO3)2+
D3Am(NO3)2+
D3AAm2+
D2AAm(NO3)+
DA2Am+
LH+ D=DMDOHEMAA-=DEHP-
4836
6342
7638
8758
10051
11068
13302
600 800 1000 1200 1400 1600 mz00
05
10
15
6x10Intens
D3Am3+
D4Am3+
D2AAm2+
D2Am(NO3)2+
D3Am(NO3)2+
D3AAm2+
D2AAm(NO3)+
DA2Am+
LH+ D=DMDOHEMAA-=DEHP-
Figure 6 Positive ESI mass spectrum of solution containing 5310-4 M DMDOHEMA 2710-4 M HDEHP 24 10-3 M HNO3 and 2710-4 M of 241Am in ethanol D and A represent DMDOHEMA and DEHP- respectively
Table 2 mz ratio and species assignment in the positive ESI-MS data for the HDEHP-DMDOHEMA -Am3+ system in ethanol (D stands for DMDOHEMA and HA for HDEHP)
Species Base peak mz
[D3Am]3+ 5633 [D4Am]3+ 7241 [D5Am]3+ 8842
[D2Am(NO3)]2+ 6342 [D3Am(NO3)]2+ 8758 [D2Am(NO3)2]+ 13302
[D2AmA]2+ 7638 [D3AmA]2+ 10051 [DAmA2]+ 13661
[DAmA(NO3)]+ 11068 [D2AmA(NO3)]+ 15884
[D2AmA2]+ 18479
4 Conclusion Electrospray ionization - mass spectrometry was used to investigate actinide complexes in organic solutions of the solvent extraction processes ESI-MS is a valuable approach for obtaining structural information about the complexes formed during solvent extraction experiments and can give information about the stability of the complexes in gas phase
In the studied system the predominant species in gas phase are consistent with the complexes observed by other techniques in solution Nevertheless although some features of the solution
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
6
structure may be preserved by the gas-phase ions such as complex stoichiometry the nature of the coordination in the gas phase species lsquoinnerrsquo vs lsquoouterrsquo may be different than in the solution species and rearrangement may occur between the solution and bare gas ion species Thus the correlation between gas phase ions and solution phase species is a topic of ongoing research
Acknowledgments This work was carried out with the financial support of ACTINET under the Joint Research Project JRP 06-15
References [1] Yamashita M and Fenn J B 1984 J Phys Chem 88 4451-4459 [2] Yamashita M and Fenn J B 1984 J Phys Chem 88 4671-4675 [3] Daniel J M Friess S D Rajagopalan S Wendt S and Zenobi R 2000 Int J Mass Spectrom 216
1-27 [4] Di Marco V B and Bombi G G 2006 Mass Spectr Rev 25 347-379 [5] Krabbe J G A de Boer R Van der Zwan G and Lingeman H 2007 J Am Soc Mass Spectrom
18 707-713 [6] Colette S Amekraz B Madic C Berthon L Cote G and Moulin C 2002 Inorg Chem 41 7031-
7041 [7] Colette S Amekraz B Madic C Berthon L Cote G and Moulin C 2003 Inorg Chem 42 2215-
2226 [8] Crowe M C Kapoor R N Cervantes-Lee F Parkanyi L Schulte L Pannell K H and Brodbelt J
S 2005 Inorg Chem 44 6415-6424 [9] Wortmann A Kisthler-Momotova A Zenobi R Heine M C Wilhelm O and Pratsinis S E 2007
J Am Soc Mass Spectrom 18 385-393 [10] Lamouroux C Moulin C Tabet J C and Jankowski C K 2000 Rapid Commun Mass Spectrom
14 1869-1877 [11] Belair S Lamouroux C Tabarant M Labet A Mariet C and Dannus P 2004 Solvent Extr Ion
Exch 22(5) 791-811 [12] Lamouroux C Rateau S and Moulin C 2006 Rapid Commun Mass Spectrom 20 2041-2052 [13] Leclerc E Guillaumont D Guilbaud P and Berthon L 2008 Radiochim Acta 96 85-92 [14] Antonio M R Chiarizia R Gannaz B Berthon L Zorz N Hill C and Cote G 2008 Sep Sci
Technol 43 2572-2605 [15] Ekberg C Fermvik A Retegan T Skarnemark G Foreman M R S Hudson M J Englund S and
Nilsson M 2008 Radiochim Acta 96 225-233 [16] Foreman M R S J Hudson M J Geist A Madic C and Weigl M 2005 Solvent Extr Ion Exch
23 (5) 645-662 [17] Nilsson M Ekberg C Foreman M R S Hudson M J Liljenzin J O Modolo G and Skarnemark
G 2006 Solv Extr Ion Exch 24 (6) 823-843 [18] Geist A Hill C Modolo G Foreman M R S J Weigl M Gompper K and Hudson M J 2006
Solvent Extr Ion Exch 24 (4) 463-483 [19] Retegan T Ekberg C Dubois I Fermvik A Johnsson Wass T and Skarnemark G 2007 Solvent
Extr Ion Exch 25( 4) 417-431 [20] Nilsson M Andersson S Drouet F Ekberg C Foreman M Hudson M Liljenzin J O
Magnusson D and Skarnemark G 2006 Solvent Extr Ion Exch 24(3) 299-318 [21] Heacuteregraves X Nicol C Bisel I Baron P and Ramain L 1999 Proceedings of the International
Conference on Future Nuclear Systems Globalrsquo99 Nuclear Technology - Bridging the Millennia Jackson Hole WY USA p585-591
[22] Baron P Heacuteregraves X Lecomte M and Masson M 2001 Proceedings of International Conference on Back-End of the Fuel Cycle From Research to Solutions (Global 2001) Paris France
[23] Gannaz B Chiarizia R Antonio M R Hill C and Cote G 2007 Solvent Extr Ion Exch 25 313-
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
7
337 [24] Foreman M R S Hudson M J Drew M G B Hill C and Madic C 2006 Dalton Trans 1645-1653 [25] Drew M G B Foreman M R S J Hill C Hudson M J and Madic C 2005 Inorg Chem Commun
8 (3) 239-241 [26] Retegan T Berthon L Ekberg C Fermvik A Skarnemark G and Zorz N (Accepted for
publication in Solv Extr Ion Exch) [27] Gannaz B 2007 CEA Report R6159 [28] Gannaz B Antonio M R Chiarizia R Hill C and Cote G 2007 Dalton Trans 4553-4562
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
8
As for Ln extraction mixed Am-HDEHP-DMDOHEMA complexes are observed From MS data the complexes formed can be written as DyAmA2(NO3) or DyAmA3 (with y le 5) for the mixed complexes Thus Am and Ln complexes seem to have the same stoichiometry which is consistent with liquid-liquid extraction data [23]
4836
6342
7638
8758
10051
11068
13302
600 800 1000 1200 1400 1600 mz00
05
10
15
6x10Intens
D3Am3+
D4Am3+
D2AAm2+
D2Am(NO3)2+
D3Am(NO3)2+
D3AAm2+
D2AAm(NO3)+
DA2Am+
LH+ D=DMDOHEMAA-=DEHP-
4836
6342
7638
8758
10051
11068
13302
600 800 1000 1200 1400 1600 mz00
05
10
15
6x10Intens
D3Am3+
D4Am3+
D2AAm2+
D2Am(NO3)2+
D3Am(NO3)2+
D3AAm2+
D2AAm(NO3)+
DA2Am+
LH+ D=DMDOHEMAA-=DEHP-
Figure 6 Positive ESI mass spectrum of solution containing 5310-4 M DMDOHEMA 2710-4 M HDEHP 24 10-3 M HNO3 and 2710-4 M of 241Am in ethanol D and A represent DMDOHEMA and DEHP- respectively
Table 2 mz ratio and species assignment in the positive ESI-MS data for the HDEHP-DMDOHEMA -Am3+ system in ethanol (D stands for DMDOHEMA and HA for HDEHP)
Species Base peak mz
[D3Am]3+ 5633 [D4Am]3+ 7241 [D5Am]3+ 8842
[D2Am(NO3)]2+ 6342 [D3Am(NO3)]2+ 8758 [D2Am(NO3)2]+ 13302
[D2AmA]2+ 7638 [D3AmA]2+ 10051 [DAmA2]+ 13661
[DAmA(NO3)]+ 11068 [D2AmA(NO3)]+ 15884
[D2AmA2]+ 18479
4 Conclusion Electrospray ionization - mass spectrometry was used to investigate actinide complexes in organic solutions of the solvent extraction processes ESI-MS is a valuable approach for obtaining structural information about the complexes formed during solvent extraction experiments and can give information about the stability of the complexes in gas phase
In the studied system the predominant species in gas phase are consistent with the complexes observed by other techniques in solution Nevertheless although some features of the solution
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
6
structure may be preserved by the gas-phase ions such as complex stoichiometry the nature of the coordination in the gas phase species lsquoinnerrsquo vs lsquoouterrsquo may be different than in the solution species and rearrangement may occur between the solution and bare gas ion species Thus the correlation between gas phase ions and solution phase species is a topic of ongoing research
Acknowledgments This work was carried out with the financial support of ACTINET under the Joint Research Project JRP 06-15
References [1] Yamashita M and Fenn J B 1984 J Phys Chem 88 4451-4459 [2] Yamashita M and Fenn J B 1984 J Phys Chem 88 4671-4675 [3] Daniel J M Friess S D Rajagopalan S Wendt S and Zenobi R 2000 Int J Mass Spectrom 216
1-27 [4] Di Marco V B and Bombi G G 2006 Mass Spectr Rev 25 347-379 [5] Krabbe J G A de Boer R Van der Zwan G and Lingeman H 2007 J Am Soc Mass Spectrom
18 707-713 [6] Colette S Amekraz B Madic C Berthon L Cote G and Moulin C 2002 Inorg Chem 41 7031-
7041 [7] Colette S Amekraz B Madic C Berthon L Cote G and Moulin C 2003 Inorg Chem 42 2215-
2226 [8] Crowe M C Kapoor R N Cervantes-Lee F Parkanyi L Schulte L Pannell K H and Brodbelt J
S 2005 Inorg Chem 44 6415-6424 [9] Wortmann A Kisthler-Momotova A Zenobi R Heine M C Wilhelm O and Pratsinis S E 2007
J Am Soc Mass Spectrom 18 385-393 [10] Lamouroux C Moulin C Tabet J C and Jankowski C K 2000 Rapid Commun Mass Spectrom
14 1869-1877 [11] Belair S Lamouroux C Tabarant M Labet A Mariet C and Dannus P 2004 Solvent Extr Ion
Exch 22(5) 791-811 [12] Lamouroux C Rateau S and Moulin C 2006 Rapid Commun Mass Spectrom 20 2041-2052 [13] Leclerc E Guillaumont D Guilbaud P and Berthon L 2008 Radiochim Acta 96 85-92 [14] Antonio M R Chiarizia R Gannaz B Berthon L Zorz N Hill C and Cote G 2008 Sep Sci
Technol 43 2572-2605 [15] Ekberg C Fermvik A Retegan T Skarnemark G Foreman M R S Hudson M J Englund S and
Nilsson M 2008 Radiochim Acta 96 225-233 [16] Foreman M R S J Hudson M J Geist A Madic C and Weigl M 2005 Solvent Extr Ion Exch
23 (5) 645-662 [17] Nilsson M Ekberg C Foreman M R S Hudson M J Liljenzin J O Modolo G and Skarnemark
G 2006 Solv Extr Ion Exch 24 (6) 823-843 [18] Geist A Hill C Modolo G Foreman M R S J Weigl M Gompper K and Hudson M J 2006
Solvent Extr Ion Exch 24 (4) 463-483 [19] Retegan T Ekberg C Dubois I Fermvik A Johnsson Wass T and Skarnemark G 2007 Solvent
Extr Ion Exch 25( 4) 417-431 [20] Nilsson M Andersson S Drouet F Ekberg C Foreman M Hudson M Liljenzin J O
Magnusson D and Skarnemark G 2006 Solvent Extr Ion Exch 24(3) 299-318 [21] Heacuteregraves X Nicol C Bisel I Baron P and Ramain L 1999 Proceedings of the International
Conference on Future Nuclear Systems Globalrsquo99 Nuclear Technology - Bridging the Millennia Jackson Hole WY USA p585-591
[22] Baron P Heacuteregraves X Lecomte M and Masson M 2001 Proceedings of International Conference on Back-End of the Fuel Cycle From Research to Solutions (Global 2001) Paris France
[23] Gannaz B Chiarizia R Antonio M R Hill C and Cote G 2007 Solvent Extr Ion Exch 25 313-
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
7
337 [24] Foreman M R S Hudson M J Drew M G B Hill C and Madic C 2006 Dalton Trans 1645-1653 [25] Drew M G B Foreman M R S J Hill C Hudson M J and Madic C 2005 Inorg Chem Commun
8 (3) 239-241 [26] Retegan T Berthon L Ekberg C Fermvik A Skarnemark G and Zorz N (Accepted for
publication in Solv Extr Ion Exch) [27] Gannaz B 2007 CEA Report R6159 [28] Gannaz B Antonio M R Chiarizia R Hill C and Cote G 2007 Dalton Trans 4553-4562
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
8
structure may be preserved by the gas-phase ions such as complex stoichiometry the nature of the coordination in the gas phase species lsquoinnerrsquo vs lsquoouterrsquo may be different than in the solution species and rearrangement may occur between the solution and bare gas ion species Thus the correlation between gas phase ions and solution phase species is a topic of ongoing research
Acknowledgments This work was carried out with the financial support of ACTINET under the Joint Research Project JRP 06-15
References [1] Yamashita M and Fenn J B 1984 J Phys Chem 88 4451-4459 [2] Yamashita M and Fenn J B 1984 J Phys Chem 88 4671-4675 [3] Daniel J M Friess S D Rajagopalan S Wendt S and Zenobi R 2000 Int J Mass Spectrom 216
1-27 [4] Di Marco V B and Bombi G G 2006 Mass Spectr Rev 25 347-379 [5] Krabbe J G A de Boer R Van der Zwan G and Lingeman H 2007 J Am Soc Mass Spectrom
18 707-713 [6] Colette S Amekraz B Madic C Berthon L Cote G and Moulin C 2002 Inorg Chem 41 7031-
7041 [7] Colette S Amekraz B Madic C Berthon L Cote G and Moulin C 2003 Inorg Chem 42 2215-
2226 [8] Crowe M C Kapoor R N Cervantes-Lee F Parkanyi L Schulte L Pannell K H and Brodbelt J
S 2005 Inorg Chem 44 6415-6424 [9] Wortmann A Kisthler-Momotova A Zenobi R Heine M C Wilhelm O and Pratsinis S E 2007
J Am Soc Mass Spectrom 18 385-393 [10] Lamouroux C Moulin C Tabet J C and Jankowski C K 2000 Rapid Commun Mass Spectrom
14 1869-1877 [11] Belair S Lamouroux C Tabarant M Labet A Mariet C and Dannus P 2004 Solvent Extr Ion
Exch 22(5) 791-811 [12] Lamouroux C Rateau S and Moulin C 2006 Rapid Commun Mass Spectrom 20 2041-2052 [13] Leclerc E Guillaumont D Guilbaud P and Berthon L 2008 Radiochim Acta 96 85-92 [14] Antonio M R Chiarizia R Gannaz B Berthon L Zorz N Hill C and Cote G 2008 Sep Sci
Technol 43 2572-2605 [15] Ekberg C Fermvik A Retegan T Skarnemark G Foreman M R S Hudson M J Englund S and
Nilsson M 2008 Radiochim Acta 96 225-233 [16] Foreman M R S J Hudson M J Geist A Madic C and Weigl M 2005 Solvent Extr Ion Exch
23 (5) 645-662 [17] Nilsson M Ekberg C Foreman M R S Hudson M J Liljenzin J O Modolo G and Skarnemark
G 2006 Solv Extr Ion Exch 24 (6) 823-843 [18] Geist A Hill C Modolo G Foreman M R S J Weigl M Gompper K and Hudson M J 2006
Solvent Extr Ion Exch 24 (4) 463-483 [19] Retegan T Ekberg C Dubois I Fermvik A Johnsson Wass T and Skarnemark G 2007 Solvent
Extr Ion Exch 25( 4) 417-431 [20] Nilsson M Andersson S Drouet F Ekberg C Foreman M Hudson M Liljenzin J O
Magnusson D and Skarnemark G 2006 Solvent Extr Ion Exch 24(3) 299-318 [21] Heacuteregraves X Nicol C Bisel I Baron P and Ramain L 1999 Proceedings of the International
Conference on Future Nuclear Systems Globalrsquo99 Nuclear Technology - Bridging the Millennia Jackson Hole WY USA p585-591
[22] Baron P Heacuteregraves X Lecomte M and Masson M 2001 Proceedings of International Conference on Back-End of the Fuel Cycle From Research to Solutions (Global 2001) Paris France
[23] Gannaz B Chiarizia R Antonio M R Hill C and Cote G 2007 Solvent Extr Ion Exch 25 313-
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
7
337 [24] Foreman M R S Hudson M J Drew M G B Hill C and Madic C 2006 Dalton Trans 1645-1653 [25] Drew M G B Foreman M R S J Hill C Hudson M J and Madic C 2005 Inorg Chem Commun
8 (3) 239-241 [26] Retegan T Berthon L Ekberg C Fermvik A Skarnemark G and Zorz N (Accepted for
publication in Solv Extr Ion Exch) [27] Gannaz B 2007 CEA Report R6159 [28] Gannaz B Antonio M R Chiarizia R Hill C and Cote G 2007 Dalton Trans 4553-4562
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
8
337 [24] Foreman M R S Hudson M J Drew M G B Hill C and Madic C 2006 Dalton Trans 1645-1653 [25] Drew M G B Foreman M R S J Hill C Hudson M J and Madic C 2005 Inorg Chem Commun
8 (3) 239-241 [26] Retegan T Berthon L Ekberg C Fermvik A Skarnemark G and Zorz N (Accepted for
publication in Solv Extr Ion Exch) [27] Gannaz B 2007 CEA Report R6159 [28] Gannaz B Antonio M R Chiarizia R Hill C and Cote G 2007 Dalton Trans 4553-4562
Actinides 2009 IOP PublishingIOP Conf Series Materials Science and Engineering 9 (2010) 012059 doi1010881757-899X91012059
8