Direct Electrochemical Immunosensor for Polychlorinated Biphenyls

Abstract

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.

Rapid Flow Injection Electrochemical Detection of Arochlor 1242 Using Stabilized Lipid Membranes with Incorporated Sheep anti‐PCB Antibody

“…The data in Figure 1 indicates that for all antigen concentrations that were tested, it takes about the same delay time (45 to 55 s) for the signal to be observed after the flow has been stopped. These response times are in agreement with the values reported in the literature for the kinetics of the arochlor 1242-anti-PCB complexation [36]. The relatively invariable delay time does not appear to be related to antigen concentration, and suggests a mechanism of response that may occur in two steps; the immunoreaction occurs to provide surface loading of complex, which may then associate as aggregates to provide electrostatic perturbation of the lipid membrane.…”

An Amperometric Enzyme Biosensor Fabricated from Polyaniline Nanoparticles

“…Enzymes [1 -4], antibodies [5,6] and even whole living cells [7,8] have been incorporated as biorecognition elements into inherently conducting polymers (ICPs). These polymers provide an effective immobilization platform with unique electron transfer capabilities, and a number of avenues for signal transduction.…”

Impedimetric immunosensors based on the conjugated polymer PPV

“…Research on electro-inactive reactions like antibody-antigen affinity binding is also being carried out. In the latter case, no direct amperometric signal can be detected, but changes occurring in the impedance of the bioactive film can be measured (Bender and Sadik, 1998;Farace et al, 2002;Katz and Willner, 2003;Laureyn et al, 2000;Lillie et al, 2001). The rapidity, sensitivity, and reproducibility of such measurements have recently been reported for differential impedance spectroscopy using the polymer polypyrrole (Sadik et al, 2002;Fernandez-Sanchez et al, 2004).…”