Development of Portable Immunoassay Instrument for Screening of PCBs in Transformer Oil

A rapid and simple procedure for the detection of PCBs in transformer oil, using an immunoassay implemented on a handheld battery-powered instrument, is described. Monoclonal anti-PCB antibody is simultaneously mixed with a gold-labeled secondary antibody and oil extract, and then flowed through a disposable cell. The absorbance change in the disposable cell, due to accumulation of the gold-labeled secondary antibody, provides a measure of PCBs present in the oil extract. Measurements of transformer oil using both the immunoassay and HRGC-HRMS showed a good correlation over the range of 0.1 mg/kg to 8.4 mg/kg total PCBs. Eighty six transformer oil samples were screened using the immunoassay at a cutoff concentration of 0.4 mg/kg total PCBs with no false positives and no false negatives observed. The same result was obtained when the cut off concentration was raised to 5.0 mg/kg. The results suggest that the described immunoassay can provide a fast and effective alternative to other procedures, such as GC-ECD for screening transformer oil for PCBs.