A Simultaneous Extraction Method for Organophosphate, Pyrethroid, and Neonicotinoid Insecticides in Aqueous Samples

Abstract

A method was developed for the extraction and analysis of 2 organophosphate, 8 pyrethroid, and 5 neonicotinoid insecticides from the same water sample. A salted liquid-liquid extraction (LLE) was optimized with a solid-phase extraction (SPE) step that separated the organophosphates (OPs) and pyrethroids from the neonicotinoids. Factors that were optimized included volume of solvent and amount of salt used in the LLE, homogenization time for the LLE, and type and volume of eluting solvent used for the SPE. The OPs and pyrethroids were quantified using gas chromatography-mass spectrometry, and the neonicotinoids were quantified using liquid chromatography-diode array detector. Results showed that the optimized method was accurate, precise, reproducible, and robust; recoveries in river water spiked with 100 ng L(-1) of each of the insecticides were all between 86 and 114 % with RSDs between 2 and 8 %. The method was also sensitive with method detection limits ranging from 0.1 to 27.2 ng L(-1) depending on compounds and matrices. The optimized method was thus appropriate for the simultaneous extraction of 15 widely applied insecticides from three different classes and was shown to provide valuable information on their environmental fate from field-collected aqueous samples.

Contamination of Water, Sediment and Fish with Residues of Pesticides Used in Cotton Production in Northern Benin

“…For the analysis of pesticide residues in water, glass bottles are generally preferred to plastic bottles to sample and store the water (Mekebri et al, 2008;Akan et al, 2013;De Perre et al, 2015) to avoid adsorption of compounds on the plastic and the subsequent underestimation of the residue concentration in the water. But, according to Lee and collaborators (2002), adsorption of pesticides on glass can occur too.…”