Chemiluminescence enhanced by carbon dots for the determination of metalaxyl

In this work, Cu-, N-, and I-codoped carbon dots (CuNICD) were synthesized using a simple hydrothermal process with citric acid as the precursor and ethylenediamine, potassium iodate, and copper chloride as dopants. It was found that the CuNICD could significantly improved the CL intensity of the Ce(IV)-NaHSO₃ system, however, this improvement was effectively suppressed by the introduction of metalaxyl (Met). Under optimal conditions, the linear detection range of Met was 0.6-80.0 μM with a detection limit of 0.08 μM. The method was successfully applied to determine Met in lettuce, tomato peel, and apple peel samples, yielding relative standard deviations between 2.46% and 4.37%. These results confirmed the high accuracy and precision of the proposed method in real-sample analysis. The mechanism of CL enhancement was investigated based on the CL spectra and the radical scavenger experiments.