Analysis of non-native fluorescent pesticides by thermo-induced and photo-induced fluorescence, a comparative study

Spectrochim Acta A Mol Biomol Spectrosc. 2023 Dec 5:302:123036. doi: 10.1016/j.saa.2023.123036. Epub 2023 Jun 23.

Abstract

This paper compares the performance of three analytical methods for the determination of pesticides in natural waters. As many pesticides are non-fluorescent, they are transformed into highly fluorescent by-products in two ways: elevated temperature in an alkaline medium (thermo-induced fluorescence - TIF); or UV irradiation in water (photo-induced fluorescence - PIF). The first method studied uses TIF, the second one uses PIF and the third one uses an automatic sampling and analysing PIF system. Analytical applications were carried out using the three methods for the determination of deltamethrin and cyhalothrin, pesticides widely used in Senegal. In both cases, the calibration curves obtained are linear without matrix effects, and the detection limits are good in the ng mL-1 range. It appears that the analytical performances of the automatic PIF method are better than the two others. The advantages and disadvantages of the three methods are then compared and discussed in term of analytical performance and usability.

Keywords: Fluorescence; Pesticides; Photo-induced; Thermo-induced.