Sensitive electrochemical detection of L-Cysteine in milk sample based on Cobalt-CNT composite modified screen-printed gold electrode

Abstract

Abstract The detection and quantification of cysteine in various food industries is crucial. An electrochemical sensor was developed using a screen-printed gold electrode (GE) that was modified with a nanocomposite of carbon nanotubes (CNTs) and cobalt phthalocyanine (CoPC) (CoPC/CNTs) for sensitive detection of L-Cysteine in milk. The CoPC/CNTs nanocomposite was synthesized using ultrasound, and then deposited onto the polished surface of the GE using an electrochemical method. The designed sensor was highly sensitive and specific, owing to the favorable catalytic properties of CoPC and the excellent electron transport capacity of CNTs. The results demonstrated that the CoPC/CNTs sensor was capable of real-time detection of L-Cysteine from 1 µM to 1 mM with a low detection limit of 0.52 µM and excellent selectivity and stability. Moreover, the developed electrodes were used to detect cysteine in milk samples, achieving a recovery rate of 95%-98%. This work provides reliable technical support for the field of food analysis and detection.