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MULTIDIMENSIONAL CHROMATOGRAPHIC
TECHNIQUES FOR MONITORING AND CHARACTERIZATION OF ENVIRONMENTAL SAMPLES
E. Mateus1, A. Ribeiro1, M. da Silva2 & P. Marriott3
1CENSE, Universidade Nova de Lisboa-FCT/DCEA, Campus Caparica, Portugal 2REQUIMTE, Universidade Nova de Lisboa-FCT/DQ, Campus Caparica, Portugal
3Monash University, Centre for Green Chemistry, Melbourne, Australia
Limitation of conventional GC
• Peak capacity
• A 50 m column has a peak capacity of 250 peaks (R=1)
o Statistical theory of component overlap - STO
A sample with 100 components in order to separate 50
will need a column with a capacity to separate 290
analites
• Peak capacity limited physically and statistically
• Insufficient separation for complex samples in 1D-GC
In 1D co-elutions
occur
Analytes
Structural Similarities
Wide Concentration Ranges
Problems in separation,
detection and identification
Adittionally ...
1
2
3
Trace analytes undetectable
Often the trace compounds
are the more important
Analytical Strategies
ü Multidimensional techniques
– Comprehensive two-dimensional gas
chromatography (GC×GC)
– Heart cutting gas chromatography
…more accurate characterization of samples
Thermal Modulator
GC×GC: The system
The GC x GC System
2 capillary columns – different phases
2 independent separation mechanisms (boiling point vs polarity)
1 interface – modulator
Column 1: Boiling point separation (e.g. DB-5) Column 2: Polarity separation (e.g.DB-17 or DB-wax)
S/N Increases
GC×GC increases sensitivity
1D-GC
GCxGC-FID
100 Hz
Polluted Soil sample
Hydrocarbons Column bleeding
Nothing?
100 Hz
E. Mateus et al, J. Chrom A, 1217, 1845- 1855, 2010.
2 D r
eten
tio
n (s
)
1D retention (min)
GC×GC: Overview of the separation structured contour plot
Scale effect: separation
seems to form a diagonal
band
Section enlargement:
3D plot shows a good
resolution
Creosote Volatiles
from railway wood sleepers
The amount of
information
implies an identification
challenge….
GC×GC: increased peak capacity
1 2
4
3
TOF:
High spectral
acquisition rate
Skewed-free spectra
MS deconvolution
GC×GC - new information about composition especially for minor
compounds not revealed in 1D-GC analysis.
GC×GC/TOFMS vs 1D-GC/TOFMS
1
2 3
4
x 5
4 5
x
6
6
x 1) dichlorobenzene 2) 1,4 - cineol 3) α-terpinene 4) Unknown Mol. W. = 150?
4
1 2
3
4
GC×GC/TOFMS vs 1D-GC/TOFMS
4 = 4 + 5 + 6 6 in 1D-GC will be hard to find
1
2 3
4
x
5
4 5
x
6
6
x
1) diclorobenzene 2) 1,4-cineol
3) α-terpinene 4) Disulfite isopropil C6H14S2
5) o-cimene 6) trimethylbenzene (pseudocumene)
GC×GC/TOFMS
GC×GC/TOFMS vs 1D-GC/TOFMS
GCxGC/TOFMS: what does it give?
Compound separation “better” detection
“true” mass spectra “better” identification
More information
Creosote Volatiles
Anolythe
Catholyte
Monitorization of
Electrokinetic remediation
Remediation technique
that
uses a low-level dc
current
as the "cleaning agent".
GCxGC/TOFMS
Anolyte
Catholyte
ca. 500 compounds Phenols S-, O-heterocycles Less basic N-heterocycles (eg. nitrile compounds) PAHs
ca. 300 compounds Azaarene compounds (basic N-heterocycles)
76 common compounds due to diffusion
processes
after the electrokinetic process
GCxGC-‐FID
INJ FID
M
GCxGC-FID
Column sets
Non Polar x Polar
Polar x nonPolar
Monitorization of
target compounds
in environmental
complex samples
LMCS
5 10 15 20 25 30 35 40
5
4
3
2
1
0
min
s
10 15 20 25 30 35 40 45 50
STTIRSO_2D_CSV_x
Column set:
Non polar x polar
GCxGC-FID
Particulate air pollution (PM10): Classical set
5 10 15 20 25 30 35 40
5
4
3
2
1
0
min
s
25 38 50 63 75 88 100
CLAT_2D_CSV_x_x
Parafins
Naphthenes mono aromatics
Di aromatics
Naphthene diaromatica
Tri aromatics
Column set :
mid polar x non polar
GCxGC-FID
Particulate air pollution (PM10): reverse set
alkanes alkenes cyclic aliphatics aromatics ketones/aldehydes alcohols acids
Remember that GCxGC provides a
Structured Retention in 2D Space?
" 2D location is function of analyte chemical property
– e.g.. boiling point and polarity
" .. and we can “see” the 2D space as a ‘chemical
property MAP’
5 10 15 20 25 30 35
6
5
4
3
2
1
0
min
s
25 38 50 63 75 88 100
HC2D2d_CSV_x_x
Standard solution with
n-hydrocarbons C9 – C30
Standard injection
GCxGC-FID
Particulate air pollution (PM10) - Standards
Column set :
mid polar x non polar
5 10 15 20 25 30 35 40
6
5
4
3
2
1
0
min
s
25 38 50 63 75 88 100
PAHS2D2D_CSV_x_x
Standard injection
GCxGC-FID
Particulate air pollution (PM10) - Standards
Standard solution with
16 PAHs mix
Column set :
mid polar x non polar
5 10 15 20 25 30 35 40
5
4
3
2
1
0
min
s
25 38 50 63 75 88 100
CLAT_2D_CSV_x_x
GCxGC-FID
Particulate air pollution (PM10) - Sample
Column set :
mid polar x non polar Standard solutions
hydrocarbons + PAHs
naphthalene
B(a)P
B(b)F B(k)F
B(a)A Chrysene
Acenaphthylene acenaphthene
Fluorene
Phenanthrene anthracene
Fluoranthrne pyrene
GCxGC-FID
Particulate air pollution (PM10) – PAHs mix
B(a)P
naphthalene
B(a)P
B(b)F B(k)F
B(a)A Chrysene
Acenaphthylene acenaphthene
Fluorene
Phenanthrene anthracene
Fluoranthrne pyrene
GCxGC-FID
Particulate air pollution (PM10) – sample
30 32 34 36 38 40
5
4
3
2
1
0
min
s
25 38 50 63 75 88 100
CLAT_2D_CSV_x_x_x_x
Benzo[a]pyrene zone
GCxGC-FID
Particulate air pollution (PM10)
30.625 30.750 30.875 31.000 31.125 31.250 31.375 31.500
5
4
3
2
1
0
min
s
15 20 25 30 35 40 45 50 55
CLAT_2D_CSV_x_x_x_x_x_x_x
Benzo[a]pyrene
GCxGC-FID
5 10 15 20 25 30 35
6
5
4
3
2
1
0
min
s
25 38 50 63 75 88 100
SOILGALP2D_CSV_x_x
Polluted Soil
GCxGC-FID
5 10 15 20 25 30 35
6
5
4
3
2
1
0
min
s
25 38 50 63 75 88 100
SOILGALP2D_CSV_x_x
5 10 15 20 25 30 35 40
5
4
3
2
1
min
s
25 38 50 63 75 88
MR4_2D2D_CSV_x_x_x
5 10 15 20 25 30 35 40
5
4
3
2
1
0
min
s
25 38 50 63 75 88 100
CLAT_2D_CSV_x_x
Air particles
Surface water
Soil
Different Matrices different chromatographic “Maps”
GCxGC-FID
MDGC-FID: Heart-Cut with Dean Switch
MD-GC / DS/CT
DS
INJ DET 2 EPC
M
2
1
DET 1
Monitorization of
target compounds
in environmental
complex samples LMCS
Dean Switch
MDGC – Cryotrap HC vs classical HC
B(a)P without Cryotrap
B(a)P with Cryotrap Ø Improved peak symmetry
Ø Higher S/N (x 4.5)
Now… Methylquinoline (MQ) in creosote samples
(m a in lib ) Q u in o lin e , 2 -‐m e th yl-‐1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 1 1 0 1 2 0 1 3 0 1 4 0 1 5 0
0
5 0
1 0 0
2 73 9 5 1
5 8 6 3 7 1 7 5 8 9 1 0 1
1 1 5 1 2 8
1 4 3
N
(m a in lib ) Q u in o lin e , 3 -‐m e th yl-‐5 0 6 0 7 0 8 0 9 0 1 0 0 1 1 0 1 2 0 1 3 0 1 4 0 1 5 0
0
5 0
1 0 0
5 1 5 7 6 37 0 7 5 8 7
8 9
1 0 1
1 1 5
1 2 8 1 4 0
1 4 3
N
(m a in lib ) Q u in o lin e , 4 -‐m e th yl-‐2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 1 1 0 1 2 0 1 3 0 1 4 0 1 5 0
0
5 0
1 0 0
3 9 5 1 5 7 6 3 7 1 7 7 8 9 1 0 4
1 1 5
1 2 8
1 4 3
N
(m a in lib ) Q u in o lin e , 5 -‐m e th yl-‐2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 1 1 0 1 2 0 1 3 0 1 4 0 1 5 0
0
5 0
1 0 0
2 7
3 9
4 1
5 1
5 7
6 3
6 5 7 5 8 78 9
1 0 1
1 1 5
1 2 8
1 4 3
N
(m a in lib ) Q u in o lin e , 6 -‐m e th yl-‐2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 1 1 0 1 2 0 1 3 0 1 4 0 1 5 0
0
5 0
1 0 0
3 9 5 1 5 8 6 3 7 1 7 58 9
1 1 5
1 4 3
N
(m a in lib ) Q u in o lin e , 7 -‐m e th yl-‐2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 1 1 0 1 2 0 1 3 0 1 4 0 1 5 0
0
5 0
1 0 0
2 73 9 5 1 5 8 6 3
7 1 7 58 9
1 1 5
1 4 3
N
(m a in lib ) Q u in o lin e , 8 -‐m e th yl-‐2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 1 1 0 1 2 0 1 3 0 1 4 0 1 5 0
0
5 0
1 0 0
3 9 5 1 5 8 6 3 7 07 5
8 9
1 1 5
1 4 3
N
MS Differences…???
Output from Mass spectra database for
Methylquinoline
shows…..
2MQ
7MQ 3MQ
6MQ 4MQ
8MQ
x-MIsoQ y-MIsoQ
(262°C)
(258°C) (252°C)
(258°C)
(248°C) (248°C)
91%
94%
92%
67%
93%
94%
6MQ
8MQ
7MQ
8MQ
6MQ
63% 7MQ
5MQ
…that frequently more
information is needed
e.g. physical properties
E. P. Mateus et al, J. Chrom. A. 1178, 215-222, 2008.
91%
94%
92%
67%
93%
94%
6MQ
8MQ
7MQ
8MQ
6MQ
63% 7MQ
5MQ
Methylquinoline
Boiling point separation, BPX5 column (non polar)
Polarity separation, BPX50 column (polar)
Human factor very
important and does
the difference!!!
Zhang Blagjo ST
Kae
Grace
Sunny
Phil Marriott
Lucy
ACKNOWLEDGEMENTS
• Project ELECTROACROSS - Electrokinetics across disciplines and continents: an integrated approach to finding new strategies for sustainable development
(FP7-PEOPLE-2010-IRSES/MC-IRSES-269289).
All the people
from Phillip Marriott Lab
at Monash University,
Australia
Dr. Rui Rocha, Dr. Jitka Zrostlíková from LECO Corp.