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 μM. Limits of detection were 0.006 μM and 0.005 μM, 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. •An electrochemical sensor was developed for the simultaneous detection of vanillin and tartrazine.•A molecularly imprinted gel (MIG) enabled specific recognition of VAN and TZ.•CuS@COOH-MWCNTs was used to electrical signal amplification.•MIG-CuS@COOH-MWCNTs/GCE sensor allowed accurate/sensitive detection of VAN and TZ in foods.