First‐Derivative Fourier‐Transform Infrared Determination of Oxadiazon in Commercial Herbicide Formulations

Abstract

A Fourier‐transform infrared (FTIR) method has been developed for the quantification of oxadiazon in herbicide formulations. The method involves the extraction of the active ingredient by sonication of the samples with CHCl₃ and direct measurement of the peak area values in first‐order derivate spectra from 1770 cm⁻¹ to 1774 cm⁻¹ corrected with a baseline point located at 1950 cm⁻¹ and after a 5‐point smoothing. A limit of detection (3 s) of 0.03 mg g⁻¹ and a typical relative standard deviation (RSD) of 1.3% were found. Results obtained were comparable with those found by liquid chromatography with UV detection. The proposed method involves a 7‐times reduction in solvent consumption and 20‐times increase of the sampling throughput compared with the chromatography procedure, and thus, it can be concluded that the proposed method is a sustainable alternative for quality control of commercial pesticide formulations.

Keywords:

• first‐derivative spectroscopy
• Fourier‐transform infrared
• herbicide formulations
• oxadiazon

Acknowledgments

The authors acknowledge the financial support of the Ministerio de Educación y Ciencia (Project CTQ2005‐05604, FEDER) and the Direcció General d'Investigació i Transferència Tecnològica de la Generalitat Valenciana (Project ACOMP/2007/131).