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01/11/96 * 1
Ergot alkaloids as novel chiral selectors in CE
Benno A. Ingelse, Jetse C. Reijenga,
Henk A. Claessens, Frans M. Everaerts
and Mirko FliegerEindhoven University of Technology, The Netherlands
Academy of Sciences of the Czech Republic
Ergot alkaloidsErgot alkaloids
N
N
H
R2 R1
R3
CH3
R4N
N
H
H N
H
CH3
H
C
O
N
C2H5
C2H5
General formula 1-allyl-terguride
Experimental:Experimental:
P/ACE 2200 Beckman InstrumentsP/ACE 2200 Beckman Instruments Capillary: 50 µm, 300/370 mm, PVA-Capillary: 50 µm, 300/370 mm, PVA-
coatedcoated BGE: BGE: -alanine/acetate + allyl--alanine/acetate + allyl-
terguride, pH 4.0, I=50 mMterguride, pH 4.0, I=50 mM UV-detection, 200 nmUV-detection, 200 nm Samples: 10Samples: 10-4 -4 MM
ExperimentalExperimental setupsetup
BGE and ergot alkaloid
BGE BGE
BGEBGE
BGE BGE
BGEBGE
Typical electropherogram Typical electropherogram using ergot skeletons as using ergot skeletons as
chiral selectorchiral selector
-0.015
-0.01
-0.005
0
0.005
0.01
0.015
0.02
0.025
0 1 2 3 4 5 6
zero
moving boundary
Abs.[AU]
time [minutes]
Influence of pH on the Influence of pH on the resolution of some racemic resolution of some racemic
organic acidsorganic acids
-0.02
-0.015
-0.01
-0.005
0
0.005
0.01
0.015
0.02
0.025
3 3.5 4 4.5 5 5.5 6 6.5 7 7.5
pH 4.0
pH 3.2
MA
HMMPA
VM
TA
MPAMA
HM
VM
Abs.[AU]
time [minutes]
Influence of terguride Influence of terguride concentration on the mobility concentration on the mobility
of the analytesof the analytes
0 5 10 15 20 25
concentration allyl-terguride [mM]
12
14
16
18
20
22
mpa1
mpa2
vm1
vm2
m(eff)
Determination of the KDetermination of the Kcc--value of vanilmandelic acid value of vanilmandelic acid
enantiomersenantiomers
1 1A
cK [C]
MA 5.5 6.3MPA 7.3 8.7HM 7.8 8.9VM 12.0 14.9TA 14.1 14.3
0 5 10 15 20 25
concentration allyl-terguride (mM)
1.00
1.10
1.20
1.30
1.40
K c
µ1/µA
Influence of MeOH on the chiral Influence of MeOH on the chiral separation of the racemic separation of the racemic
organic acidsorganic acids
-0.06
-0.05
-0.04
-0.03
-0.02
-0.01
3 4 5 6 7 8 9
50% MeOH, pH*=5.3
0% MeOH, pH=4.0
MA
MPAHM
TA
MA
MPAHM
VM
TA
Abs.[AU]
time [minutes]
Influence of terguride Influence of terguride concentration on the mobility of concentration on the mobility of
the analytes in 50% MeOHthe analytes in 50% MeOH
0 10 20 30 40 50 60 70
concentration allyl-terguride [mM]
8
10
12
14
16
mpa1
mpa2
vm1
vm2
m(eff)
Determination of the KDetermination of the Kcc-value of -value of --methyl-phenylacetic acid methyl-phenylacetic acid enantiomers using MeOHenantiomers using MeOH
1 1A
cK [C]
MA 11.2 13.2MPA 10.6 13.2HM 12.1 13.2VM 13.5 14.9TA 6.7 7.2
0 5 10 15 20 25
concentration allyl-terguride (mM)
1.00
1.10
1.20
1.30
1.40
K c
µ1/µA
Full separation of some Full separation of some racemic organic acids using 25 racemic organic acids using 25
mg/mL allyl-terguridemg/mL allyl-terguride
-0.002
0.002
0.006
0.01
0.014
0.018
6 8 10
MA
HM
TA
MPA
Abs.[AU]
time [minutes]
Selectivity with and without MeOHSelectivity with and without MeOH
0 20 40 60
Concentration allyl-terguride [mM]
0.00
0.02
0.04
0.06
mandelic acid
50% MeOH 0% MeOH
S
0 20 40 60
Concentration allyl-terguride [mM]
0.00
0.02
0.04
0.06
tropic acid
50% MeOH 0% MeOH
S
ConclusionsConclusions
Allyl-terguride has great potential as a Allyl-terguride has great potential as a chiral selector for organic acidschiral selector for organic acids
The dissociated acid forms stereoselective The dissociated acid forms stereoselective complexes with the ergot alkaloidcomplexes with the ergot alkaloid
Solubility of the ergot-alkaloid in water is Solubility of the ergot-alkaloid in water is limitedlimited
Methanol increases solubility Methanol increases solubility Methanol influences stereoselectivityMethanol influences stereoselectivity