A Simple and Rapid Purification Method for the Analysis of all PCB Congeners in Environmental Samples

Abstract

The conventional methods of PCB analysis used for testing environmental samples and measuring all PCB congeners are complicated in operation and sometimes insufficient to perform purification.
Therefore, we developed a simple and rapid purification method for the analysis of all PCB congeners in environmental samples by improving upon the existing analysis method used for electrical insulating oils. This existing method uses heated, multi-layer silica gel column/alumina column which cannot recover low chlorinated PCB in which only one aromatic ring is substituted with chlorine and high chlorinated tetra-ortho PCB.
At the outset, we prepared a column set that consisted of a purification column and a concentration column. The purification column was filled with sulfuric acid silica gel for refining the sample. The concentration column was filled with alumina and silver-modified alumina for facilitating selective adsorption and elution of PCB. The recovery rate of high chlorinated tetra-ortho PCB was improved when the column set was used under the non-heating cleanup condition. However, that of monochlorinated biphenyl did not show any improvement. Afterwards, an additional amount of silica gel was stacked in layers on the sulfuric acid silica gel to boost the purification column's function. As a result, the loaded sample was contained and degradation of low chlorinated PCB by sulfuric acid silica gel was prevented. Thus, all PCB congeners were recovered using this improved column set.
Subsequently, the above column set was also used to purify the samples of sediment and fish tissues. The effective cleanup was confirmed by the chromatogram of GC/ECD and GC/MS. Furthermore, the performance of this method was evaluated by the certified reference materials. The result of the study showed that the proposed method has satisfactory quantitative capability and repeatability.
Hence, this method was found to be effective for analyzing the presence of all PCB congeners in environmental samples.