Analysis of Insecticide Gels Containing Fipronil by Rp HPLC

Abstract

The article considers fipronil determination by the method of RP HPLC in isocratic mode with ultraviolet detection at 280 nm. The analysis of insecticidal gels containing fipronil and fipronil mixture with chlorpyriphos was carried out. The possibility and expediency of determining the isomeric composition of fipronil were considered. The conditions for carrying out extraction of insecticides from gel matrices containing food attractive, including additional processing by ultrasound, were determined. The developed mode of extraction of active ingredients (fipronil and chlorpyriphos) is based on the preferred homogenization of the gel sample with a minimum amount of water followed by extraction with isopropanol acidified with acetic acid. The proposed scheme differs from the previously realized chloroform extraction by the stage of sample preparation. However, under these conditions in case of the gel matrix it is possible to achieve a high degree of homogeneity of the sample and to prevent possible hydrolysis of the target components. At the same time, the selected conditions are well combined with the polarity of the mobile phase upon direct separation. Selected chromatography modes allow identifying the title compound in real insecticides without overlapping signals from other extractable components using the trivial stationary phases. The possibility and expediency of carrying out chromatographic analysis to determine the optical isomers of the title compounds with different insecticidal activity have been considered. The optimal concentration range of fipronil determination in the working solution is from 0.005 to 0.15 mg/ml (chlorpyriphos, from 0.002 to 0.15 mg/ml). The limit of determination of substance in the working solution/swabs is 0.0005 mg/ml.