Direct electrochemical immunosensor for polychlorinated biphenyls

A direct electrochemical immunosensor has been developed for the determination of polychlorinated biphenyls (PCBs) in water. The assay is based on the measurement of the current due to the specific binding between PCB and anti-PCB antibody-immobilized conducting polymer matrix. The linear dynamic range of the immunosensor is between 0.3 and 100 ng/mL with a correlation coefficient of 0.997 for Aroclor 1242. The method detection limits for Aroclors 1242, 1248, 1254, and 1016 were 3.3, 1.56, 0.39, and 1.66 ng/mL respectively, and at a signal-to-noise (S/N) ratio of 3. The immunosensor exhibited high selectivity for PCBs in the presence of potential interference such as chlorinated anisoles, benzenes, and phenols. The highest cross-reactivity measured for chlorinated phenolic compounds relative to Aroclor 1248 was less than 3%. Recoveries of spiked Aroclors 1242 and 1254 from industrial effluent water, rolling mill, and seafood plant pretreated water at 0.5 and 50 ng/mL ranged from 103 to 106%. The effect of ionic compounds on detection indicates that no significant change in immunosensor signal was observed within the uncertainty of the assay procedure. The detection method may be applied for continuous monitoring of effluent such as waste streams and groundwater.