gcxgc-(ms) methods · pdf filespectral quality: no skewing . modulator control single...
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GCxGC-(MS) methods
Pim Leonards
Outline
• Principles of GCxGC
• Selection of detectors
• PCB, PBDE analysis
• Other examples
Injector Detector
Modulator
1st column 2nd column
•Selection of modulator •6 different modulators:
•SWEEPER •LMCS •Quad N2(l) jet •Dual CO2 jet •Loop CO2
•CFT
Selection of proper column combination
Principles of GCxGC
Selection 1st and 2nd dimension GC columns
• 1st dimension
– Apolar type phases:
DB-1, DB-5, CP-Sil 8 type of columns
2nd dimension
-Polar type and phase selective phases:
DB-XLB (proprietary) fused-silica
007-65HT (65% phenyl-methylpolysiloxane)
LC-50 (50% liquid crystalline-methylpolysiloxane)
How does it work? Cryogenic modulator
How does GCxGC work ?
How does GCxGC work ?
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0 s 10 s
How does GCxGC work ?
Separation on the 2nd dimension column
How does GCxGC work ?
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Principle and contour plots
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46 min
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10 s
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1st
2nd
2nd
1st
Contour plot
Detectors for GCxGC systems
• Fast scanning detectors
• Acquisition rate >20 Hz
• Low dead volume detectors
Commercial equipment
• GCxGC-FID
• GCxGC-ECD
• GCxGC-qMS
• GCxGC-ToF-MS
• GCxGC-AED not commercial available
GCxGC-μECD
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2n
d d
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sio
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(s)
1st dimension retention time (min)
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45 50 55 60 65 70
155
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126
85
114 106
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124
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102 100
101 120
125
88
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98,119
40,77
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55
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42,66
58,79
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46,48
72 6F-47
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69,73
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22,37
20,35
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27 19
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16,33
28
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14
12,13
15 11
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2
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115
76
7
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25,31
97,118
108,123
86 87
4MeO-49
4OH-42
3F-100
6F-66 4’F-69
2OH-28
BB52
BB49
4’F-27
BB15
1 4’F-25 3’F-28
BB101
6OH-47
4OH-49
154
me-TBBP-A
BB153
6OH-99
144 161
168
153
TBBP-A
139
131,158,140
141
160
142
159 167
HBCD
138
166
156
184
128
BB169
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192
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181
173,190 204
4’,6F-199 2,4’F-198
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203 205
208 207
206
4’F-208
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41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73
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80
4’F-160
3F-119
6MeO-47
203
198
183 181
PCAs
HBCD
138
139
153
TBBP-A
144
154
85
116
99 101
100
4’F-27
27 BB153
154
me-TBBP-A
GCxGC-μECD 125 PBDE’s DB-1x007-65HT
Korytar et al., J Chrom A, 1100 (2005) 200–207
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PCDD/Fs
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PCBs
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PBBs
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PBDEs
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PCDEs
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OCPs
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Toxaphenes
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PCNs
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PCDTs
PCAs
GCxGC-μECD various contaminants
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1st dimension retention time (min)
Korytar et al., J. Chromatogr. A, 2005. 1086, 29-44
DB-1 LC-50
GCxGC-μECD different column combination
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PBDEs
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PCBs
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PCNs
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PCDTs
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PCDEs
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PBBs
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PCDD/Fs
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Toxaphene
2n
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1st dimension retention time (min)
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OCPs
PCAs
DB-1 007-65HT
Korytar et al., 2005. J. Chromatogr. A, 1086, 29-44
GCxGC-μECD dust sample PBDEs
Polychlorinated alkanes P. Korytar et al. / J. Chromatogr. A 1086 (2005) 29–44
DB-1×007-65HT
Background matrix separation from dioxins
4F1 4D1 5F1
5F2
5D1
6F1
6F2
6F3
6D1
6D2
6D3
7F1
6F4
7D1
7F2
OCDD
OCDF
1st dimension retention time [min]
2nd d
imen
sion r
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tion t
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[s]
GCxGC-ECD, DB-XLB x LC-50
P. Korytar et al. / J. Chromatogr. A 1100 (2005) 200–207
Background matrix
GCxGC-MS
GCxGC with qMS
• Requirements
fast acquisition
spectral quality: no skewing
Modulator control
Single quadrupole MS
Dual-jet CO2 modulator
GC
Set-up
Quadrupole MS
Rf setup time: 10.4 ms
Scan rate: 10000 amu/s
Scan width (amu): @ 50Hz: 96
@ 33 Hz: 195
@ 25 Hz: 296
High acquisition rates • short Rf setup time • fast scanning
No skewing mass ratio plot (m/z 330/326)
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Data point number
Mas
s R
atio
Shimadzu qMS
Quality of spectra
P. Korytar et al. / J. Chromatogr. A 1067 (2005) 255–264
Mass range scanned
P. Korytar et al. / J. Chromatogr. A 1067 (2005) 255–264 259
GCxGC-qMS
• Fast enough
• Selective enough – separation of coeluters
• Limited scanning range (300 Da)
• Not sensitive enough in EI – NCI required
Eel extract GCxGC-qMS PBDE analysis
P. Korytar et al. / J. Chromatogr. A 1067 (2005) 255–264
GCxGC ToFMS
• Fast scan speed: 100-500 Hz
• No mass skewing
• Automated search
GCxGC-ToF-MS, Tern egg Western Scheldt
PCBs
PCAs
Brominated compounds
1st dimension retention time (min)
2n
d d
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sio
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(sec
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Screening chemicals in household dust GCxGC-ToFMS of an hexane extract of dust
Hilton et al., 2010. J. Chrom A, 1217 (2010) 6851–6856
Chlorinated and brominated compounds in house dust
• >10,000 peaks detected
• 145 compounds contain chlorine or bromine
Hilton et al., 2010. J. Chrom A, 1217 (2010) 6851–6856
Cl and Br compounds
Other compounds identified in household dust
PAHs Phthalates
Hilton et al., 2010. J. Chrom A, 1217 (2010) 6851–6856
GCxGC-AED oil
Sulphur
Carbon
van Stee et al. / J. Chromatogr. A 1019 (2003) 89–99
Bioassay
Bioassay
Bioassay
Effect-directed analysis (EDA)
x Y
x
x
x x
Y
Y
Y
complex mixture of compounds
x x Y
1st Fractionation
2nd Fractionation
Chemical identification
Bioassay confirmation
Combined sample treatment scheme
chemical and bioassay analysis
Houtman et al. 2006 •Sediment sample from a harbour •Bioassays
•Dioxin like compounds (DR-CALUX) •Estrogenic compounds (ER-CALUX)
•Chemical identification •GC-MS •GCxGC-ToFMS
Houtman et al., 2006, Chemosphere 65, 2244–2252
Bioassay activity of the sediment
Houtman et al., 2006, Chemosphere 65, 2244–2252
Active fraction GCxGC-ToFMS
Houtman et al., 2006, Chemosphere 65, 2244–2252
Fraction 4-B Fraction 4-B
Fraction 5-B Fraction 2
PAHs
Me-PAHs
PAHs Hormones
Identified compounds and explained bioassay activity
• 76% of the estrogenic activity was explained by 17α-, 17β-estradiol and estrone
• 38% of dioxin-like activity explained by PAHs
Summary
• GCxGC is a powerful separation technique
• Separation of interfering compounds and matrix
• GCxGC is especially suitable for the separation of complex mixtures
• GCxGC combined with mass spectrometry can be used for the identification of “new” flame retardants