Selective and Sensitive Detection of Malathion Pesticide with CdSe Quantum Dots as Ligand-Exchange Probes

Here, a facile, efficient, and sensitive method is reported for detecting malathion based on ligand exchange between the surface capping molecules of CdSe quantum dots and malathion in organic solution. Under optimal conditions, there was a linear relationship between the relative fluorescence intensity (Imax/I) and the logarithm of malathion concentration ranging from 9.08 x 10(-10) to 3.03 x 10(-7) mol/L (Signal to Noise ratio = 3), and the detection limit was 3.03 x 10(-10) mol/L. A relative standard deviation of 1.25% was detected for 9.08 x 10(-9) mol/L malathion (N = 5). The method was finally validated by the detection of malathion in emulsifiable concentrate formulation and vegetable samples, and the obtained results were highly consistent with those of gas chromatography.