1 Enantioselective Enantioselective separation of separation of chiral chiral PCBs by multidimensional PCBs by multidimensional gas chromatography techniques. gas chromatography techniques. Application to real samples Application to real samples L.R. L.R. Bordajandi Bordajandi , L. Ramos, B. , L. Ramos, B. Gómara Gómara and and M.J. González M.J. González Depart Depart . . of of I.A. & I.A. & Environ Environ . . Chem Chem . IQOG (CSIC) Madrid, . IQOG (CSIC) Madrid, Spain Spain
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Enantioselective separation of chiral PCBs by multidimensional … · 2011-07-26 · 1 Enantioselective separation of. chiral. PCBs by multidimensional gas chromatography techniques.
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1
EnantioselectiveEnantioselective separation ofseparation ofchiralchiral PCBs by multidimensional PCBs by multidimensional gas chromatography techniques. gas chromatography techniques.
Application to real samplesApplication to real samples
L.R. L.R. BordajandiBordajandi, L. Ramos, B. , L. Ramos, B. GómaraGómara andandM.J. GonzálezM.J. González
Although the enantiomeric enrichment of chiral PCBs in living organisms has been reported since 1994
Mussels (Hühnerfuss et al., 1994); Sharks (Blanch et al.,1996); Otters ( Ramos et al., 1996); Cetaceans (Vetter and Schurig, 1997; Reich et al., 1998); Predatory birds (Gómara et al., 2006); Human breast milk (Schurig et al., 1995; Bordajandi et al., 2005)
The knowledge about the mechanisms involved in the enantioselective degradation is limited
The analytical separation of chiral PCBs is a rather difficult task
4 Introduction
Until now, no single enantioselective GC column has been able to separate the 19 chiral PCBs
80 100 110 120 130 140 150
PCB 45
PCB 95 PCB 91PCB 136
PCB 149
PCB 176
90
The separation into enantiomers of the 19 chiral congenershas been achieved by the use of capillary columns
with different types of chiral stationary phases
5 Chiral stationary phases
terttert..-- buthyldimethylsilylbuthyldimethylsilyl ββ--CD CD
Chirasil-Dex 2,3,62,3,6--tritri--OO--methyllmethyll ββ--CD CD chemicaly bonded to polysiloxane
BGB-176SE 20% 2,320% 2,3--didi--OO--methylmethyl--66--OO--terttert..--buthyldimethylsilylbuthyldimethylsilyl--ββ--CDCDdiluted in SE-52 (5 % phenyl methylpolysiloxane)
PCBs 45, 91, 95, 131, 136, 149, 176
BGB-172 25% 2,3,625% 2,3,6--terttert..--butbutyyldimetldimethyhylsillsilyyll--ββ--CD CD diluted in PS086 (15 % phenyl methylpolysiloxane)
L. Ramos, B. Jiménez, M. Fernández, L. Hernández and M.J. González. Organohalogen Comp 26, 1996
23 Human breast milk
Enantiomeric Enantiomeric enrichment
PCBs 91, 95 y 149 EF EF ≈≈ 0.5 racemic mixture0.5 racemic mixtureEF ≈ EF ≈ ≠≠ 0.5 depending of the sample0.5 depending of the samplePCBs 84 y 174EF < 0.5 EF < 0.5 exceesexcees ofof the the 22ndnd enantenant..PCBs 132, 135, 171, 176 y 183
enrichment
PCB 171 and 183 high enantiomeric enrichment of the 2PCB 171 and 183 high enantiomeric enrichment of the 2ndnd enantiomerenantiomer
100 110 120 130 Min
Standard
PCB 183 PCB 171
Breast milk
L.R. Bordajandi and M.J. González. Organohalogen Comp 67, 2005
24 Enantioselectve degradation
EnantioselectiveEnantioselective transformation oftransformation of chiralchiral PCBs in PCBs in living organismsliving organisms
The species could influence theThe species could influence the enantioselectiveenantioselectivedegradation ofdegradation of chiralchiral PCBsPCBs
The mechanisms involved are still unknownThe mechanisms involved are still unknown
PCBs could already arrive to the living organisms with PCBs could already arrive to the living organisms with a nona non--racemicracemic composition, ifcomposition, if enantioselectiveenantioselectivetransformations have previously occurredtransformations have previously occurred
25 Milk and dairy products
Dairy products:
Milk , cheese Milk , cheese && yogurtyogurt from three species: cow, goat from three species: cow, goat & & sheepsheep
PCBs 135, 136, 176 EF < 0.5 EF < 0.5 exceesexcees ofof thethe 22ndnd enantiomerenantiomer
PCBs 84, 91, 95, 132, 149, 174 EF = 0.5 EF = 0.5 racemicracemic mixture mixture
Enantiomeric Enantiomeric enrichmentenrichment
PCBsPCBs 171 171 andand 183 183 HighHigh deviationdeviation fromfrom thethe racemicracemic compositioncomposition in in somesome samples samples
L.R. Bordajandi, L. Ramos and M.J. González. Organohalogen Comp, 66, 2004
Milk and dairy products26
PCB 183PCB 183
0,00
0,50
1,00
0,00
0,50
1,00
0,00
0,50
1,00
EF
EF
EF
Cow
Goat
Sheep
milk cheese yoghurt
Milk and dairy products27
PCB 183PCB 183
0,00
0,50
1,00
0,00
0,50
1,00
0,00
0,50
1,00
EF
EF
EF
Cow
Goat
Sheep
milk cheese yoghurt
28 EnantioselectiveEnantioselective transformation oftransformation of chiralchiral PCBsPCBs
TheThe enantiomericenantiomeric enrichmentenrichmentofof PCBs 171 and 183 foundPCBs 171 and 183 foundin humans could be due to in humans could be due to the uptake of nonthe uptake of non--racemicracemic
PCBs through the dietPCBs through the diet
Conclusions29
Conclusions1. Heart-cut MDGC and GC x GC are suitable to separate PCB
enantiomers in real samples.
2. The differences found between species in the enantiomeric enrichment of chiral PCBs could be due to both,
The species capacity to degraded PCBs
The non-racemic PCB uptake through the diet
More research and data are needed to drawmore reliable conclusions
30 AcknowledgementsAcknowledgements
DoñanaDoñana National Park (National Park (CSICCSIC), La Laguna University (Spain) and ), La Laguna University (Spain) and Centro Centro StudiStudi CetaceiCetacei (Italy)(Italy)for sampling collectionfor sampling collection
CSICCSIC, CM,, CM, INIAINIA,, CICYTCICYT (Spanish institutions)(Spanish institutions)for financial supportfor financial support
Prof. V. Prof. V. SchürigSchürig ((TübingenTübingen University,Germany)University,Germany)for kindly providing for kindly providing chirasilchirasil--DexDex columnscolumns
My working group atMy working group at CSICCSIC and other collaborators and other collaborators L.R. L.R. Bordajandi Bordajandi L. RamosL. RamosB. B. Gómara Gómara B. B. JiménezJiménezR. SerranoR. Serrano O. RamosO. RamosG. BlanchG. Blanch S. ReichS. Reich