Double responsive analysis of carbaryl pesticide based on carbon quantum dots and Au nanoparticles

B, N-doped carbon quantum dots (CQDs) with an emission peak at 490 nm was prepared by a hydrothermal method. It was found that the fluorescence of CQDs could be effectively quenched by Au nanoparticles (AuNPs) with the absorption peak at 520 nm. Thiocholine (TC), which was produced from acetylcholine (ACh) hydrolysis catalyzed by acetylcholinesterase (AChE), could induce the aggregation of AuNPs along with a drop in the absorption at 520 nm and result in the recovery of quenched CQDs fluorescence. When carbaryl was introduced, which inhabited the catalytic activity of AChE, thus the aggregation of AuNPs and the recovery of CQDs fluorescence was decremented. On the basis of above phenomena, we established a colorimetric and fluorescent double reading method for carbaryl determination. Under the optimum conditions, the fluorescence response was strongly correlated with carbaryl concentration in the 0.20-150 mu g/L range, and the absorbance response was linearly proportional to the concentration of carbaryl in the range of 0.2-20 mu g/L. This method was used to the determination of carbaryl in tap and lake water samples with high precision and accuracy, indicating the potential of the method in practical applications with simple operation, good accuracy and high sensitivity.