An L-cysteine based sensor for Cu2+ detection applicable for both environmental water and human plasma.

Abstract

A flexible electrochemical sensor with high sensitivity and specificity is developed using gold nanoparticles (AuNPs) and a reduced graphene oxide/molybdenum disulfide (rGo-MoS2) composite modified screen printed carbon electrode (SPCE), with L-cysteine (L-Cys) as a probe for Cu2+ target recognition. Owing to the AuNPs/rGo-MoS2, the electron transference ability is improved by increasing the specific surface area of the working electrode, and a high sensitivity is achieved. Meanwhile, the bidentate chelation of L-Cys to Cu2+ contributes to a good selectivity. Using differential pulse voltammetry (DPV) for spiked standard Cu2+, the test results show a dynamic range from 0.1 μM to 100 μM, a detection limit of 0.020 μM, and a high sensitivity of 1.190 μA μM-1. Furthermore, detection in both environmental water and human plasma samples demonstrates a wide applicability of this sensor in various matrices, and an excellent feasibility for environmental and clinical applications.