Application of flow injection analysis--photo-induced fluorescence (FIA-PIF) for the determination of α-cypermethrin pesticide residues in natural waters.

Flow injection analysis combined with photo-induced fluorescence (FIA-PIF) has been applied for the determination of α-cypermethrin pesticide residues in Senegalese natural waters, using organic solutions and cyclodextrin (β-cyclodextrin and 2-hydroxypropyl-β-cyclodextrin) aqueous media. The α-cypermethrin insecticide has a very weak natural fluorescence, but it is converted into strongly fluorescent photoproduct(s) by UV irradiation. Cyclodextrins were found to enhance the PIF signal. FIA parameters, including mobile phase flow rate, injected volume, and reactor length, were optimized. Analytical performances of the FIA-PIF method for the determination of α-cypermethrin were satisfactory, with concentration linear dynamic ranges over one to two orders of magnitude and with rather low limits of detection and limits of quantification, in the ng mL(-1) range, and relative standard deviations comprised between 1.2% and 3.8%. Application of FIA-PIF for the analysis of fortified natural water samples collected from Senegal yielded good recovery values (84-112%). Because of its high sampling rate, the FIA-PIF method constitutes a rapid analytical tool, useful for quantification of α-cypermethrin residues in natural waters.