Novel sulphur-selective method for simultaneous determination of thiram and asomate based on carbon dots and its application in fruits

Thiram (THI) and asomate (ASO) are frequently detected agrochemicals in food samples due to widespread use as fungicides. However, their detection suffers from matrix interference, or the necessity of derivatization before measurement. Integrating HPLC with a post-column carbon dots (CDs)-enhanced chemiluminescence (CL) system makes it possible to simultaneously separate and selectively detect ASO and THI in fruit samples free of derivatization and deep purification. The studies on mechanisms demonstrated that CD intermediates of anionic radical were responsible for the remarkable CL enhancement of ASO or THI. The CL intensity is directly proportional to the fungicide concentration, with the ranges of linearity for ASO and THI being 5-250 μg·L^-1 (<i>R</i> ^<i>2</i> <i>= 0.9993</i>) and 4-200 μg·L^-1 (<i>R</i> ^<i>2</i> <i>= 0.9986</i>), respectively, and the corresponding limits of detection (S/N = 3) being 1.61 and 1.33 μg·L^-1, respectively. The developed method enables the exploration of the novelly sulphur-targeted CL application based on carbon nanomaterials.