Screen-printed electrochemical immunosensors for PCB detection

An electrochemical enzyme immunoassay for polychlorinated biphenyls (PCB) using carbon-based screen-printed disposable electrodes as the solid-phase for reagent immobilization and also as the signal transduce has been optimized. Horseradish peroxidase (HRP) was conjugated with Ag or Ab and used as the enzyme label. Hydrogen peroxide and ferrocenemonocarboxylic acid (FCA) were used as substrate and mediator in order to determine the HRP activity in the range 10(-8)-10(-10)M. Indirect and direct competitive assays for PCB have been presented. The advantage of this approach is the relatively fast analysis time (30 min) in comparison with a lest based on microtiter assay plates (14 h); moreover, the use of disposable screen-printed electrodes eliminates the problems of fouling and surface regeneration of the electrochemical device.