Highly selective molecularly imprinted gel-based electrochemical sensor with CuS@COOH-MWCNTs signal amplification for simultaneous detection of vanillin and tartrazine in foods

Herein, we report the successful development of a highly selective molecularly imprinted gel (MIG)-based electrochemical sensor for the simultaneous detection of vanillin (VAN) and tartrazine (TZ) in foods. A glassy carbon electrode (GCE) was first modified with conductive CuS@COOH-MWCNTs, after which the obtained CuS@COOH-MWCNTs/GCE was further functionalized by deposition of a molecularly imprinted chitosan-based gel crosslinked and stabilized using benzidine. The MIG allowed specific recognition of VAN and TZ, whilst the CuS@COOH-MWCNTs component was used for signal amplification. Under optimized testing conditions, the developed MIG-CuS@COOH-MWCNTs/GCE sensor allowed simultaneous detection of VAN and TZ, showing a linear response over the concentration range 0.03-125 mu M. Limits of detection were 0.006 mu M and 0.005 mu M, respectively. Analysis of liqueur and white vinegar samples spiked with VAN and TZ using the developed sensor afforded excellent recoveries (92.2%-109.7%). Further, the sensor was successfully applied to analyze the content of VAN and TZ in two kinds of vanilla ice cream, with results consistent with analyses performed using a national standard method.

Automated summary

In this study, a highly selective molecularly imprinted gel (MIG)-based electrochemical sensor was developed for simultaneous detection of vanillin (VAN) and tartrazine (TZ) in foods. The sensor showed a linear response over the concentration range of 0.03-125 mu M, with detection limits of 0.006 mu M and 0.005 mu M for VAN and TZ, respectively. The developed sensor demonstrated excellent recoveries (92.2%-109.7%) when applied to analyze liqueur, white vinegar, and vanilla ice cream samples spiked with VAN and TZ.