Immunoassay for polychlorinated biphenyls (PCB) using screen printed electrodes

A disposable sensor for the detection of polychlorinated biphenyls (PCB) in soil samples has been developed using polyclonal antibodies as recognizing element and carbon-based screen printed electrochemical electrodes as sens ing element. The analysis scheme has been based on the competitive enzyme l inked immunosorbent assay (ELISA) protocol. The immunochemical reaction has been carried on using an Immobilon(TM) membrane as the solid phase. The en zyme used for the measurement of the immunoreaction has been alkaline phosp hatase whereas the electrochemical substrate was Lu-naphthyl phosphate. The extent of the immunochemical reaction has been monitored by means of an el ectrochemical product using screen-printed electrodes and differential puls e voltammetry (DPV). The screen-printed electrodes were characterized and t heir electrochemical performance tested. Soil samples were assayed using a simple extraction kit. A detection limit of 0.3-0.6 ng/ml in solution was a chieved with the proposed method regardless of PCB mixture standard. (C) 19 99 John Wiley & Sons, Inc.