Fiber optic immunosensor for polychlorinated biphenyls.

Abstract

A fiber optic immunosensor, consisting of a quartz fiber coated with partially purified polyclonal anti-PCB antibodies (Abs), was used to detect polychlorinated biphenyls (PCBs). The optical signal was generated by the binding and subsequent fluorescein (FL) conjugate of 2,4,5-trichlorophenoxybutyrate (TCPB) to the Ab-coated fiber. The Abs, immobilized on the fiber, bound TCPB-FL with high affinity, saturably and reversibly. TCPB and PCBs competed with TCPB-FL for binding and decreased fluorescene in a concentration-dependent manner, with a detection limit of 10 ppb TCPB. The biosensor detected 1 ppm Aroclors, but not polychlorinated pesticides, polychlorinated phenols, or trichlorobenzene. It was more selective for TCPB at 1 ppm than the four tested Aroclors (i.e. 1016, 1232, 1250, and 1262) by 1.4-, 2.2-, 5.5-, and 3-fold, respectively. It detected Aroclor 1242 added to river waters and standard reference soil samples with reasonable accuracy. Advantages of this biosensor are its fast detection time (seconds to minutes), high sensitivity, and reversibility. 37 refs., 11 figs., 3 tabs.