A sensitive electrochemical sensor for lead based on gold nanoparticlesitrogen-doped graphene composites functionalized with L-cysteine-modified electrode

摘要

Glassy carbon electrodes (GCEs) modified with L-cysteine (L-cys)/gold nanoparticles (AuNPs)itrogen-doped graphene (NG) composite were prepared to fabricate a novel electrochemical sensor for lead. AuNPs were uniformly dispersed into NG and L-cys was successfully decorated on AuNPs through the S-Au bond. The L-cys/AuNPs/NG exhibited a well-distributed nanostructure and high responsivity toward Pb(II). The results indicated that L-cys/AuNPs/NG/GCE exhibited the highest peak current, reflecting that the L-cys/AuNPs/NG composites showed the best response signal toward Pb2+. Under optimized conditions, a linear relationship between the current intensity and Pb2+ concentration was obtained in a range of 0.5-80 mu g L-1 with a detection limit of 0.056 mu g L-1 (S/N = 3). The analytical interference procedure and practical application were investigated using the prepared electrode, which exhibited an acceptable result.