Analysis of PCB by on-line coupled HPLC-HRGC

Abstract

On-line coupled HPLC-GC has been used for the fractionation and analysis of polychlorobiphenyls (PCB) according to their planarity. HPLC elution with porous graphitic carbon (PGC) as stationary phase, enables fractionation of PCB into classes according to the amount of ortho-substitution, which is related to congener toxicity. This is a preliminary step before GC analysis, which enables complete separation of PCB congeners according to vapour pressure. Conditions for HPLC-HRGC coupling were optimised, in particular the appropriate proper HPLC solvent was selected, because it determines eluent strength and selectivity and the transfer conditions. Different solvents were studied -n-hexane, dichloromethane, benzene, toluene, and their mixtures.Samples containing PCB standards and the commercial mixtures Aroclor 1242 and 1254 were analysed. Dichloromethane-n-hexane, 1 : 1, was selected as mobile phase for separation of poly-ortho from mono-ortho PCB; benzene-dichloromethane 30:70 resulted in the best separation of the most retained non-ortho-substituted PCB. Under these conditions the co-solvent trapping procedure, performed by adding 4% ethylbenzene as co-solvent, was used as transfer technique to overcome the drawback of losses of volatile congeners.Appropriate analysis conditions were successfully used to fractionate the technical PCB for-mulationsAroclor

Analysis of polychlorinated biphenyls in transformer oils by automated on-line coupling reversed phase liquid chromatography-gas chromatography using the through oven transfer adsorption desorption (TOTAD) Interface

“…Standard samples of PCBs have been analysed employing on-line coupled LC-GC, using normal phase in liquid chromatography and a loop-type interface to transfer PCB fractions [20]. However, the analysis of real samples, such as oil is a complex task because the normal phase in the LC step requires back-flushing of the column after each analysis in order to remove the heavy compounds, which may cause several problems that affect the performance of the column.…”