Carbon Dots-based Nanozyme Catalyst for Sensitive and Selective Colorimetric Detection of Nitrite
(Objective)A nanozymatic colorimetric method for the determination of nitrite(NO-2)in tobacco leaf samples was established.(Meth-ods)Based on the excellent peroxidase-like(POD)catalytic activity of copper and iodine doped carbon dots(Cu,I-CDs),colorless 3,3',5,5'-tetramethylbenzidine(TMB)can be oxidized to blue oxTMB under acidic conditions and in the presence of H2O2,and an obvious absorption peak appears at 652 nm.With the addition of nitrite(NO2-),based on the formation of NO2,the peroxidase-like catalytic activity of the system was enhanced,and the blue color of the solution was deepened.A new colorimetric method for the detection of nitrite was established.(Results)In the range of 0.05-17.5 mg/L,the A654 value showed a good linear relationship with the concentration of NO2-,and the detection limit was 0.0126 mg/L(S/N=3).(Conclusion)At the same time,the constructed detection system has outstanding performance in recovery rate and an-ti-interference,and has good detection accuracy,and the recovery rate of standard addition is above 96.9%.The sensor has been successfully applied to the detection of tobacco leaf samples.The method has the characteristics of fast,simple,stable and strong specificity.