Chromatographic separation, polychlorinated biphenyls

Two-dimensional GC can be used to separate complex mixtures of polyaromatic compounds, and MS used to subsequently identify the compounds. In this method, the original sample is injected into a gas chromatograph with one type of column. As the components exit the first GC, they are fed into a second GC, with a different column, for further separation and finally into a mass spectrometer. In this way, compounds that coeluted from the first column are separated on the second. Focant et al. [19] were able to separate polychlorinated dibenzo-p-dioxin (PCDD), polychlorinated dibenzofuran (PCDF), and coplanar polychlorinated biphenyl (cPCB) using this type of analytical procedure, including isotope dilution TOF-MS. These compounds are frequently found as contaminants in soils surrounding industrial settings thus, the ability to separate and identify them is extremely important [6,12,19],... 

The sample is extracted with a mixture of hexane, acetone and water. After separation, the hexane phase is reduced in volume and divided into two aliquots, one of which is first shaken with 7% fuming sulphuric acid to remove lipids, and then with cyanide to eliminate interference by elemental sulphur. The other aliquot is evaporated to dryness and heated with ethanolic potassium hydroxide. The two aliquots are injected into a gas chromatograph fitted with a glass capillary column and an electron capture detector. Hexabromobenzene is used as an internal standard. Polychlorinated biphenyls are determined quantitatively by comparing the peaks of the sample with those of Clophen A... 

Naikwadi KP, Karasek FW. 1986. Gas chromatographic separation of 2,3,7,8-tetrachlorodibenzo-p-dioxin from polychlorinated biphenyls and tetrachlorodibenzo-p-dioxin isomers using a polymeric liquid crystal capillary column. J Chromatogr 369 203-207. 

Kania-Korwel, I. Vyas, S.M. Song, Y. Lehmler, H.-J., Gas chromatographic separation of methoxylated polychlorinated biphenyl atropisomers J. Chromatogr. A 2008,1207, 146-154. 

Fuoco R, Colombini MP, Samcova E (1993) Individual determination of ortho-and non-ortho substituted polychlorinated biphenyls (PCBs) in sediments by high performance liquid chromatographic pre-separation and gas chromatography - ECD detection. Chromatographia 36, 65-70. 

Zurmiihl, T., Development of a method for the determination of phthalate esters in sewage sludge including chromatographic separation from polychlorinated biphenyls, pesticides and polyaromatic hydrocarbons, Ana/yjr, 115, 1171-1175, 1990. 

Berg, O. W., P. L. Diosady, and G. A. V. Rees. 1972. Column chromatographic separation of polychlorinated biphenyls from chlorinated hydrocarbon pesticides, and their subsequent gas chromatographic quantitation in terms of derivatives. Bull. Environ. Contam. Toxicol. 7 338. 

I. Benito, J.M. Saz, M.L. Marina, J. Jimenez-Barbero, M.J. Gonzdlez and J.C. Diez-Masa, Micellar electrokinetic capillary chromatographic separation of polychlorinated biphenyl congeners,... 

Concentrate the extract in a rotary evaporator or in a Kuderna-Danish evaporator to approx. 1 ml (without an air flow). Inject the extract into a chromatographic column of 12 mm diameter and 15 cm height, which has previously been packed to half height with n-hexane, then to a height of 7 cm with florisil and above that 1 cm of hexane-toluene mixture 1 1, maintaining a drop rate of 1 to 2 drops/second (3 to 5 ml/min). For the separation of non-polar interfering substances (in particular polychlorinated biphenyls... 

Other organic compounds Other dangerous substances include hydrocarbons (fats and oils), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and dioxins. Chromatographic methods (gas or liquid chromatography) are extensively used for separation and quantification of these groups. 

The sample is extracted with solvent and the extract is treated to remove interfering substances, if needed. The sample extract is injected into a gas chromatograph. The components are separated as they pass through the capillary column and polychlorinated biphenyl compounds, if present, are detected by an electron capture detector (ECD). 

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