GC/ECD Peak Pattern Analysis with GPC Pretreatment for Determination of PCBs in Transformer Oil

A new peak pattern analysis on GPC/GC/ECD allowing estimation of the total PCB concentration and the Kanechlor composition for transformer oil is described. The oil is treated with a diatomite column containing fuming sulfuric acid, followed by a connected column of silica gel. After elution the sample is further treated by gel permeation chromatography (GPC) and the collected fraction is analyzed by GC/ECD. An algorithm is described to fit the measured GC/ECD peak pattern with a combination of four peak patterns corresponding to the four Kanechlor mixtures, resulting in the total PCB concentration and a predictive proportion of Kanechlors in the sample. Measurements of 19 transformer oil samples using both GPC/GC/ECD and HRGC/HRMS showed a good correlation over the range of 0.2 mg/kg to 2.4 mg/kg total PCBs.