Ultrasensitive Determination of L-Cysteine Based on Its Enhancement to Electrochemiluminescence of CdS Quantum Dots with Cd2+Rich Surface / 分析化学

ABSTRACT

A novel electrochemiluminescence ( ECL) method for the determination of L-cysteine ( L-Cys) was established. water-soluble CdS quantum dots ( QDs) with Cd2+rich surface were synthesized via a controllable one-poe approach. The mercapto group in L-cysteine molecule can specifically interact with excessive Cd2+on the surface of CdS QDs, resulting in enhancement of ECL intensity of the CdS QDs, which can be used for the detection of L-Cys. Under the optimal experimental conditions, the enhancement of ECL intensity was linear with the concentration of L-Cys in the range of 5. 0×10-9-1. 0×10-5 mol/L. The limit detection of (S/N=3) was 1. 2×10-9 mol/L. In comparison with other methods for detecting L-Cys, this method is more simple and selective, and can be applied to detect L-Cys in real sample with satisfactory results.