Electrodeposition immobilized molybdenum disulfide quantum dots and their electrochemiluminescence application in the detection of melamine residues in milk powder

Abstract

In this paper, one-step hydrothermal and electrodeposition methods were used to prepare a MoS₂ quantum dot (QD) solid-phase electrochemiluminescent (ECL) electrode for the detection of melamine residues in milk powder. With the assistance of chitosan, MoS₂ QDs fixed by the one-step electrodeposition method show better ECL performance than those by traditional deposition methods due to better dispersibility and stability. Based on the quenching of the MoS₂ QDs ECL signal by melamine, quantitative detection of melamine in the sample was performed. The structure and morphology of a MoS₂-CHIT/indium tin oxide (ITO) solid-phase ECL electrode were characterized by TEM and XPS, and melamine was detected by the ECL method using a three-electrode system. The proposed sensor exhibited good linearity in the range of 1.00 × 10⁻¹¹ to 1.00 × 10⁻⁷ mol L⁻¹ (ΔI = 12 100.62 + 1009.93 lg c (mol L⁻¹), R² = 0.997), and the method shows the advantages of simplicity and sensitivity compared to traditional detection methods. The interference of common ions in milk powder on the modified electrode was within 5%, and the recovery rate of real sample detection was within 97–98%. As a result, the proposed method is suitable for detecting melamine residues in milk powder.