A new chemiluminescence system based on nitrogen-sulfur doped carbon quantum dots for highly sensitive detection of uric acid in human plasma and urine samples

Carbon quantum dots (CQDs) are a fascinating class of luminescent nanomaterials that comprise discrete, quasi-spherical carbon nanoparticles with sizes below 10 nm. They typically display high quantum yield fluorescence with interesting behavior.Recently nitrogen-sulfur doped carbon quantum dots (N,S-CQDs) have been introduced and attracted considerable interest in various areas [1]. In this work, N,S-CQDs were prepared by a hydrothermal method and characterized by fluorescence spectra and transmission electron microscopy. The effect of as-prepared CQDs on the chemiluminescence (CL) of colloidal MnO2-luminol system was investigated. The results showed that N,S-CQDs remarkably increase the intensity of CL emission. Moreover, the effect of uric acid on the S,N-CQDs–MnO2–luminol CL system was studied and found that the CL intensity of this system is significantly declined by uric acid. Based on this finding a sensitive and selective method was developed for detection of uric acid. The calibration curve was linear in the concentration range of 0.05 to 1.0 µM. The method was successfully applied to the determination of uric acid in human plasma and urine samples.