DIRECT ELECTROCHEMICAL IMMUNOSENSOR FOR POLYCHLORINATED-BIPHENYLS

A direct electrochemical immunosensor has been developed for the deter mination of polychlorinated biphenyls (PCBs) in water. The assay is ba sed on the measurement of the current due to the specific binding betw een PCB and anti-PCB antibody-immobilized conducting polymer matrix. T he 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 metho d 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 t he presence of potential interference such as chlorinated anisoles, be nzenes, and phenols. The highest cross-reactivity measured for chlorin ated phenolic compounds relative to Aroclor 1248 was less than 3%. Rec overies of spiked Aroclors 1242 and 1254 from industrial effluent wate r, rolling mill, and seafood plant pretreated water at 0.5 and 50 ng/m L ranged from 103 to 106%. The effect of ionic compounds on detection indicates that no significant change in immunosensor signal was observ ed within the uncertainty of the assay procedure. The detection method may be applied for continuous monitoring of effluent such as waste st reams and groundwater.