Selective enrichment and electrochemical determination of Cu in mushroom using L-Cysteine functionalized Fe3O4@Au nanoparticles

Abstract

An analytical method was developed to enrich and detect Cu2+ using L-Cysteine functionalized Fe3O4@Au nanoparticles (NPs). Fe3O4 was synthesized by coprecipitation method, and then Au layer was coated on Fe3O4 by chemical reduction. The L-Cysteine molecule assembled on Fe3O4@Au NPs surface through the Au-S bond. Cu2+ could be captured by L-Cysteine and enriched on Fe3O4@Au NPs surface. Under magnetic field, the L-Cysteine functionalized Fe3O4@Au NPs carrying with Cu2+ was attached on the surface of magnetic glassy carbon electrode (MGCE). The key experiment conditions including supporting electrolyte, self-assembly time, electrolyte pH and preconcentration time were studied and optimized. Under optimal conditions, L-Cysteine/Fe3O4@Au/MGCE showed a good linear relationship in Cu2+of 1–50 μg L−1, and limit of detection was 0.26 μg L−1. The proposed method was further evaluated in the presence of other inorganic cations and anions, and it was found that the interference was almost negligible. All results proved that the established method had a good application prospect in Cu detection.