Quality control of pesticide using infrared spectroscopic coupled with fingerprint analysis

• A pesticide IR spectral database was established. • An IR-based pre-treatment method was proposed. • The method can eliminate the negative effect of pesticide formulation. The public concern and increasing awareness of pesticide calls for methods available to assure quality and authenticity. Spectra matching is widely used in various applications including the search for a spectrum of an unknown compound in an existing spectral database and quality control by means of comparing the spectra of products with standards. Although the infrared spectroscopy (IR) fingerprint has many applications in a lot of areas, there are several limitations in pesticide. The pesticide formulation is a significant impediment against analyzing IR fingerprint of pesticide with similarity estimation. In the present study, a novel strategy combining Fourier-transform infrared spectroscopy (FT-IR) analysis was developed and validated to allow comprehensive analysis and rapid authentication of pesticide. A pesticide IR spectral database which included 604 pesticide standards was established. A simple, fast, and environmentally friendly IR-based pre-treatment method was proposed that can eliminate the negative effect of pesticide formulation on similarity estimation. In order to verify the effectiveness of proposed method, 30 pesticide samples were randomly collected from market, including liquid and solid, with the concentration of active components from 1% to 80%. For 30 samples, the proposed strategy resulted in a 90% accuracy rate and a 3.33% error rate based on the liquid chromatography (LC) data. It is therefore clear that IR spectral database combining with the proposed pre-treatment appear to be a promising tool for monitoring and analysis in the pesticide industry.