Silicon quantum dots based fluorescent probes for detecting methyl parathion pesticide residues in potato, tap water and Yellow River

In this paper, a novel ratiometric fluorescent probe based on silicon quantum dots (SiQDs) has been developed for the sensitive detection of methyl parathion pesticide residues. The silicon quantum dots were prepared by a simple hydrothermal reaction process using 3-Aminopropyltriethoxysilane (APTES) as silicon resource and were characterized by the analysis of transmission electron microscopy, FTIR spectroscopy, and X-ray photoelectron spectroscopy. The silicon quantum dots displayed characteristic blue fluorescence emission at 440 nm. Tyrosinase can catalyze the oxidation of tyramine to form dopamine. Then, dopamine can interact with silicon quantum dots and effectively change the position of its fluorescence emission for redshifting to 540 nm. In the presence of organic phosphorus pesticides (OPPs), the activity of tyrosinase was inhibited, resulting in the inability to generate dopamine and the fluorescence emission at 440 nm remaining unchanged. As a model of organic phosphorus pesticides, methyl parathion (MP) was determined using this method, and the fluorescence intensity response values showed a good linear relationship with methyl parathion concentration in the range of 50-90 nM, with a detection limit of 0.149 nM. Due to its good performance of relative low detection limit, good selectivity and high reproducibility, this sensing system has been successfully applied to the detection of methyl parathion in environmental water samples and potato samples, which showed good prospects for application in the detection of organic phosphorus pesticide residues in more real samples.