Electrochemical biosensors for rapid determination of pesticide residues in agricultural products

Abstract

The biosensors, consisting of immobilized antibodies which were for specific recognition to target molecules and electrodes which were able to convert the binding event between antigen and antibody to a detectable signal, were developed for rapid detection of organophosphate (OPs) pesticides. Anti-OPs antibodies were immobilized onto indium-tin-oxide (ITO) coated interdigitated microsensor electrodes (IMEs). The Faradaic impedance spectra, presented as Nyquist plots (Z' vs Z'') and Bode diagrams, (impedance vs frequency) were recorded in the frequency range from 1Hz to 100 kHz respectively. A linear relationship between the electron-transfer resistance and concentrations of OPs pesticide was found ranging from 0.1 ppm to 100 ppm. The regression equations were Y = 658 X +1861, with the correlation coefficient of 0.977. The biosensing procedure was simple and rapid, and could be completed within 1 h.