Short Communication: An Electrochemical Immunosensor Based on Microfluidic Chip for Detection of Chlorpyrifos

With increasing of the abuse of overdose pesticides in agriculture, the threat to human health has become prominent, which leads to the urgent need for rapid detection of pesticide residues. In this article, an impedance immunosensor based on microfluidic chip was developed for rapid detection of pesticide residues in vegetable samples. This microfluidic chip consisted of a detection microchamber inlet and outlet microchannel. Gold interdigitated array microelectrode (IDAM) was embedded in the microchannel of microfluific chip. Using chlorpyrifos as the model compound, the methods of nanometer materials modified electrodes and protein A used for binding antibody's Fc fragment are used for the fabrication of the micro-fluidic chip immunosensors. The binding of chlorpyrifos target onto the antibody-modified IDAM surface produced a sensitive impedance change. And the impedance change was detected by the electrochemical impedance spectroscopy (EIS). The effect of experiment conditions of different pH value and the assembly time on the impedance sensor were also studied. Under the optimum operating conditions, this microfluidic chip immunosensor showed a broad linear response range, a high specificity and sensitivity and high stability. Moreover, the on-chip immunosensor can be used for direct detection of practical samples.