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  • 1995-1999  (2)
  • Analytical Chemistry and Spectroscopy  (2)
  • 1
    ISSN: 0935-6304
    Keywords: Bornane congeners ; toxaphene compounds ; heart-cut multidimensional gas chromatography ; enantioselectivity ; chiral GC separation ; biological samples ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---The enantiomeric ratios of the chlorinated bornanes, 2-exo, 5,5,9,9,10, 10-heptachlorobornane (B[20030]-(022)), 2-endo,3-exo,5-endo,6-exo,8, 8,10,10-octachlorobornane (B[12012]-(202), Parlar No. 26), 2-exo,3-endo,6-endo,8,9,10,10-heptachlorobornane (B[21001]-(112)), 2,2,5,5,9,9, 10,10-octachlorobornane (B[30030]-(022), Parlar No. 38), 2-endo,3-exo,5-endo6-exo,8,8,9,10,10-nonachlorobornane (B[12012]-(212), Parlar No. 50), and 2,2,5,5,8,9,9,10,10-nonachlorobornane (B[30030]-(122), Parlar No. 62) were determined in a hake liver (Merluccius merluccius) and in two whitebeaked dolphin blubber (Lagenorynchus albirostris) samples. The analysis was performed by heart-cut multidimensional gas chromatography using an electron capture detector (ECD). Ultra 2 (5%-phenyl-95%-methylsilicone) was used as stationary phase in the first column and enantioselectivity was obtained in the second column with a phase consisting of a mixture of OV-1701 and heptakis(2,3,6-O-tert- butyldimethylsilyl)-β-cyclodextrin (10 : 1). All reference standards were also tested on the enantioselective column alone. The comparison of the two systems showed that deviations of ±0.12 from the racemic enantiomer ratio can be observed for the single column due to co-eluting impurities which are present in the reference standards. In most of the heart-cut chromatograms of the biota samples about 15 peaks could be found, showing the importance of a multidimensional separation system for an interference-free quantification by ECD. In all biological samples a significant deviation from the racemic enantiomer ratio was found for B[30030]-(022) (Parlar No. 38) and for B[30030]-(122) (Parlar No. 62). This indicates that an enantioselective disposition of the congeners occurs. In addition, considerations are presented concerning the relationship between congener structure and enantiomeric disposition.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 21 (1998), S. 298-302 
    ISSN: 0935-6304
    Keywords: Toxaphene ; thermal decomposition ; stationary phases ; gas chromatography ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Some toxaphene congeners are thermally unstable under commonly used gas chromatographic temperature conditions. The thermal stability of the 22 commercially available congeners has been studied at four different heating rates on four stationary phases Ultra 2 (5%-diphenyl-95%-dimethylpolysiloxane), a liquid crystalline phase (N,N′-bis(p-butoxy-benzylidene)-α,α′-bis-p-toluidine), Rtx-2330 (90%-biscyanopropyl-10%-phenylcyanopropyl-polysiloxane), and heptakis-(2,3,6-O-t-butyldimethylsilyl)-β-cyclodextrin (TBDMS-CD) diluted in OV-1701-OH. A substantial degradation of the congeners Parlar 39, 42, 50, 56, 58, and 62 could be observed on the cyanopropyl polysiloxane stationary phase. Furthermore, the applied temperature program and stationary phase had an influence on the signal areas. These factors are important for a quantitative analysis.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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