Simultaneous Separation of Coplanar and Chiral Polychlorinated Biphenyls by Off-Line Pyrenyl-Silica Liquid Chromatography and Gas Chromatography. Enantiomeric Ratios of Chiral Congeners

Abstract

A method for the unambiguous determination of 41 key polychlorinated biphenyls (PCBs) (including coplanar and chiral congeners) and the enantiomeric ratio of chiral congeners is described. The method includes a fractionation step using a 2-(1-pyrenyl) ethyldimethylsilylated silica column for separating the polychlorinated biphenyls according to the number of chlorine atoms in the ortho positions. High-resolution gas chromatography with an electron capture detector and an achiral column was used to determine the PCB congener content in each fraction. The enantiomeric ratio of chiral congeners was calculated by high-resolution gas chromatography with a mass spectrometry detector using a chiral column. The method was found to be inexpensive, rapid, effective, and reliable under the operational conditions proposed. It eliminates the main coelution problems among the polychlorinated biphenyl congeners. It also makes it possible to determine the enantiomeric ratio of nine chiral congeners using monodimensional gas chromatography. The method was applied successfully to the analysis of the coplanar and atropisomeric polychlorinated biphenyl congeners in dolphin liver samples. The enantiomeric ratio of nine chiral congeners is also reported for the first time.

Chiral separation of polychlorinated biphenyls using a combination of hydroxypropyl-γ-cyclodextrin and a polymeric chiral surfactant

“…Early developments of chiral chromatography for PCBs were conducted on chiral stationary phases via HPLC [8][9][10]. However, only in few occasions chiral PCBs were separated.…”

Rapid enantiomeric separation of polychlorinated biphenyls by electrokinetic chromatography using mixtures of neutral and charged cyclodextrin derivatives

“…relevance because each enantiomer may have differGas chromatography (GC), usually employed to ent toxicity, activity or metabolic pathways. Moreseparate PCB congeners, has also been employed to perform the separation of chiral PCBs [5][6][7][8][9][10][11]. Nevertheless, the characteristics of capillary electro- and flexibility) make this technique competitive with GC in the field of the enantiomeric separations [12].…”

Fractionation of chlorinated and brominated persistent organic pollutants in several food samples by pyrenyl-silica liquid chromatography prior to GC–MS determination

“…In a previous paper [20], a 2-(1-pyrenyl) ethyldimethylsilylated silica gel column was used for simultaneous separation of coplanar and chiral PCBs based on the number of chlorine atoms in ortho positions, using n-hexane at 0.5 mL/min and 25 • C. Since these conditions were not appropriate for the separation of PCBs from PBDEs and PBBs, all of which are considered "non-polar" compounds, different chromatographic conditions were assayed. Firstly, increasing percentages (0, 1, 2, and 3%) of toluene were added to n-hexane to increase the elution power of the mobile phase and to decrease the retention time of the most retained congeners of each family.…”