A validated and fast procedure for FTIR determination of Cypermethrin and Chlorpyrifos

A FTIR methodology has been developed for the simultaneous determination of Cypermethrin and Chlorpyrifos in pesticide commercially available formulations. The method involves the extraction of both active principles with CHCI3 and direct measurement of the peak area values between 1747 and 1737 cm(-1) corrected with a baseline defined at 2000 cm(-1) for Cypermethrin and peak height values established at 1549 cm(-1) corrected using a baseline situated at 1650 cm(-1) for Chlorpyrifos. The limits of detection achieved were of the order of 0.7 and 0.4% (w/w), and the relative standard deviation 0.4 and 0.2% for Cypermethrin and Chlorpyrifos, respectively. The developed procedure provided statistically comparable results with those obtained by HPLC, for a series of commercial samples, which validated the FTIR method. The procedure developed reduces organic solvent consumption, per sample preparation, from 51 ml CH3CN required for HPLC to 2.5 ml CHCI3, and reduces waste generation also increasing the sample measurement frequency, from 3 to 30 samples/h, as compared with the HPLC-UV reference method. (c) 2005 Elsevier B.V. All rights reserved.