Enzyme-induced Cu2+/Cu+ conversion as the electrochemical signal for sensitive detection of ethyl carbamate.

Traditional enzyme-linked immunosorbent assay (t-ELISA) method suffers from its relatively low sensitivity or accuracy in the detection of trace level of analyte in complicated samples. In this work, to extend the application of ELISA in practical samples, a newly electrochemical immunoassay (ECIA) was developed based on an enzyme-induced Cu2+/Cu+ conversion for the determination of ethyl carbamate (EC). Wherein, three rounds of signal transformation-the catalysis of ALP enzyme, the conversion of Cu2+/Cu+ and signal output of square wave voltammetry (SWV), can be realized to obtain higher sensitivity as compared to t-ELISA. The ECIA method combines the advantages of electrochemistry and ELISA, behaving superior detection performance, such as good selectivity, high sensitivity, and low background signal. For the wine samples, the method showed a linear detection range from 2.5 nM to 2.5 × 104 nM with a limit of detection of 2.28 nM (S/N = 3), which reveals that the ECIA sensor is a promising platform for the detection of trace level of EC in practical samples.