Polychlorinated biphenyls chromatography

The values of n and the corresponding N which are necessary to resolve 50-90% of the constituents of a mixture of 100 compounds are listed in Table 1.5, thus making clear the limitations of one-dimensional chromatography. For example, to resolve over 80 % of the 100 compounds by GC would require a column generating 2.4 million plates, which would be approximately 500 m long for a conventional internal diameter of 250 p.m. For real mixtures, the situation is even less favourable to resolve, for example, 80 % the components of a mixture containing all possible 209 polychlorinated biphenyls (PCBS) would require over lO plates. 

In general, capillary gas chromatography provides enough resolution for most determinations in environmental analysis. Multidimensional gas chromatography has been applied to environmental analysis mainly to solve separation problems for complex groups of compounds. Important applications of GC-GC can therefore be found in the analysis of organic micropollutants, where compounds such as polychlorinated dibenzodioxins (PCDDs) (10), polychlorinated dibenzofurans (PCDFs) (10) and polychlorinated biphenyls (PCBs) (11-15), on account of their similar properties, present serious separation problems. MDGC has also been used to analyse other pollutants in environmental samples (10, 16, 17). 

Figure 13.1 Monitor (FID) (a) and analytical (ECD) (b) channel responses for PCB congeners in Aroclor 1254, showing selection of the six heart-cut events Frr-st columns, HT8 second columns, BPX5. Reprinted from Journal of High Resolution Chromatography, 19, R. M. Kinghorn et al., Multidimensional capillar-y gas chr omatography of polychlorinated biphenyl marker compounds , pp. 622-626, 1996, with per-mission from Wiley-VCH.

Janak K, G Becker, A Colmsjo, C Ostman, M Athanasiadou, K Valters, A Bergman (1998) Methyl sulfonyl polychlorinated biphenyls and 2,2-bis(4-chlorophenyl)-l,l-dichloroethene in gray seal tissues determinated by gas chromatography with electron capture detection and atomic emission detection. Environ Toxicol Chem 17 1046-1055. 

An important application of carbon-skeleton gas chromatography is the simplification of the analysis of complex samples such as polychlorinated biphenyls, polybrominated biphenyls and polychloroalkanes [709-711], These complex mixtures of halogenated isomers produce multiple peaks when separated by gas chromatography, making quantitation difficult. The isomers have identical carbon skeletons, resulting in a very simple chromatogram after hydrodechlorination. 

Bordajandi, L.R., Korytar, P., De Boer, J., Gonzalez, M.J. (2005). Enantiomeric separation of chiral polychlorinated biphenyls on P-cyclodextrin capillary columns by means of heart-cut multidimensional gas chromatography and comprehensive two-dimensional gas chromatography applications to food samples. J. Sep. Sci. 28, 163-171. 

Glausch, A., Blanch, G.P., Schurig, V. (1996). Enantioselective analysis of chiral polychlorinated biphenyls in sediment samples by multidimensional gas chromatography-electron-capture detection after steam distillation-solvent extraction and sulfur removal. J. Chromatogr. A 723, 399 104. 

Glausch, A., Nicholson, G.J., Eluck, M., Schurig, V. (1994). Separation of the enantiomers of stable atropisomeric polychlorinated biphenyls (PCBs) by multidimensional gas chromatography on Chiraldex. J. High Res. Chromatogr. 17, 347-349. 

Aparicio I, Santos JL, Alonso E (2007) Simultaneous sonication-assisted extraction, and determination by gas chromatography-mass spectrometry, of di-(2-ethylhexyl)phthalate, nonylphenol, nonylphenol ethoxylates and polychlorinated biphenyls in sludge from waste-water treatment plants. Anal Chim Acta 584 455 161... 

Westcott, J. W., Bidleman, T. F. (1982) Determination of polychlorinated biphenyl vapor pressures by capillary gas chromatography. J. Chromatogr. 210, 331-336. 

Amberlite XAD-2 resin is a suitable adsorbent for polychlorinated biphenyl and chlorinated insecticides (DDT and metabolites, dieldrin) in seawater. These compounds can be suitably eluted from the resin prior to gas chromatography [356,358]. 

Picer and Picer [357] evaluated the application ofXAD-2, XAD-4, and Tenax macroreticular resins for concentrations of chlorinated insecticides and polychlorinated biphenyls in seawater prior to analysis by electron capture gas chromatography. The solvents that were used eluted not only the chlorinated hydrocarbons of interest but also other electron capture sensitive materials, so that eluates had to be purified. The eluates from the Tenax column were combined and the non-polar phase was separated from the polar phase in a glass separating funnel. Then the polar phase was extracted twice with n-pentane. The -pentane extract was dried over anhydrous sodium sulfate, concentrated to 1 ml and cleaned on an alumina column using a modification of the method described by Holden and Marsden. The eluates were placed on a silica gel column for the separation of PCBs from DDT, its metabolites, and dieldrin using a procedure described by Snyder and Reinert [359] and Picer and Abel [360]. 

Alford-Stevens, A.L., J.W. Eichelberger, and W.L. Budde. 1988. Multilaboratory study of automated determinations of polychlorinated biphenyls and chlorinated pesticides in water, soil, and sediment by gas chromatography/mass spectrometry. Environ. Sci. Technol. 22 304/312. 

Ballschmiter K. and M. Zell. 1980. Analysis of polychlorinated biphenyls (PCB) by glass capillary gas chromatography. Fres. Z. Analyt. Chem. 302 20-31. 

Duinker, J.C., D.E. Schulz, and G. Petrik. 1988b. Multidimensional gas chromatography with electron capture detection for the determination of toxic congeners in polychlorinated biphenyl mixtures. Anal. Chem. 60 478-482. 

Dunnivant, F.M. and A.W. Elzerman. 1988. Determination of polychlorinated biphenyls in sediments, using sonication extraction and capillary column gas chromatography-electron capture detection with internal standard calibration. Jour. Assoc. Offic. Anal. Chem. 71 551-556. 

Schulz, D.E., G. Petrick, and J.C. Duinker. 1989. Complete characterization of polychlorinated biphenyl congeners in commercial Aroclor and Clophen mixtures by multidimensional gas chromatography-electron capture detection. Environ. Sci. Technol. 23 852-859. 

Storr-Hansen, E. and T. Cederberg. 1992. Determination of coplanar polychlorinated biphenyl (CB) congeners in seal tissues by chromatography on active carbon, dual-column high resolution GC/ECD and high resolution GC/high resolution MS. Chemosphere 24 1181-1196. 

Alford Stevens et al. [49] carried out a multi-laboratory study of automated gas chromatography-mass spectrometric determinations of polychlorinated biphenyls in soil. The influence of various factors on the accuracy of analytical results were studied. Shaker extraction for 12.5h followed by Florisil chromatography were demonstrated to be the most reliable methods for extraction and clean-up. 

McMurtrey et al. [65] investigated the feasibility of determining polychlorinated biphenyls adsorbed on sediments by a procedure involving pyrolytic desorption at 1000°C, followed by gas chromatography and mass spectrometry. The procedure was capable of detecting polychlorinated biphenyl in sediment at the lOmg kgy1 level. 

Alford Stevens et al. [49] have reported on an inter-laboratory study of the determination of polychlorinated biphenyls in environmental sediments. Electron capture gas chromatography and mass spectrometry were used to identify and determine polychlorinated biphenyls. For electron capture, an overall standard deviation of 30% was achieved while mass spectrometry gave 38%. 

Japenga et al. [56] determined polychlorinated biphenyls and chlorinated insecticides in River Elbe estuary sediments by a procedure in which the sediments were pretreated with acetic acid, mixed with silica and Soxhlet-extracted with benzene/hexane. Humic material and elemental sulphur were removed by passing the extract through a chromatographic column containing basic alumina, on which sodium sulphite and sodium hydroxide were adsorbed. Silica fractionation was followed by gas chromatography to analyse chlorinated pesticides, polychlorinated biphenyls and polyaromatic hydrocarbons. Recovery experiments with standard solutions gave recoveries of 90-102%. 

A method has been described [55] for separating polychlorinated biphenyls from chlorinated insecticides. This procedure involves adsorption chromatography on alumina and charcoal columns, elution with increasing fractional amounts of hexane on alumina columns, and with acetone-diethyl ether on charcoal columns. The polychlorinated biphenyls and chlorinated pesticides are then determined by gas chromatography-mass spectrometry on the separate eluates without interference. 

Stalling DL, Tindle RC, lohnson IL. 1972. Cleanup of pesticide and polychlorinated biphenyl residues in fish extracts by gel permeation chromatography. J Assoc Off Anal Chem 55 32. 

Korver MP, Burse VW, Needhain LL, et al. 1991. Determination of mirex in human blood scrum containing polychlorinated biphenyls by using packed column gas chromatography. J Assoc Off Anal Chem 74(5) 875-877. 

A principal components multivariate statistical approach (SIMCA) was evaluated and applied to interpretation of isomer specific analysis of polychlorinated biphenyls (PCBs) using both a microcomputer and a main frame computer. Capillary column gas chromatography was employed for separation and detection of 69 individual PCB isomers. Computer programs were written in AMSII MUMPS to provide a laboratory data base for data manipulation. This data base greatly assisted the analysts in calculating isomer concentrations and data management. Applications of SIMCA for quality control, classification, and estimation of the composition of multi-Aroclor mixtures are described for characterization and study of complex environmental residues. 

Pesticides (14, 85), polychlorinated biphenyls (86, 87) and herbicides (88) are usually separated by this technique also. In analytic work, however, the detection sensitivity of the selective detectors used in gas chromatography could not be achieved (59). Nevertheless, sUch substances can be separated by liquid chromatography with no attendant decomposition problems and no derivatization, making the procedure significantly simpler. i... 

Haglnnd, P., L. Asplnnd, U. Jamberg, and B. Jansson. 1990. Isolation of mono- and non-ort/ro-polychlorinated biphenyls from biological samples by electron donor acceptor high performance liqnid chromatography using a 2-(l-pyrenyl)ethyldimethylsilylated silica colunm. Chemosphere 20 887-894. 

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