Quantification of organophosphate insecticides in drinking water in urban areas using lyophilization and high-performance liquid chromatography–electrospray ionization-mass spectrometry techniques

A sensitive method for the quantification of eight organophosphate pesticides in water samples at the ng L−1 concentration level has been developed. These organophosphates include pesticides, insecticides and herbicides used in agricultural applications. A lyophilization with simple solvent extraction followed by selective analysis using a liquid chromatography–mass spectrometry method was used. This method was accurate (≥98.9%), as it possessed limits of detection and quantification in the 4.9–51 and 16.5–171 ng L−1 ranges, respectively. Furthermore, the coefficients of variations (≥0.999) were less than 8.2% at the low ng L−1 end of the linear range of the method. In addition, the percentage recovery of all pesticides at the 0.1 μg L−1 levels ranged from 96% to 103%. This method was then used for the quantification of organophosphates in drinking and bore water samples collected from different parts of urban areas. We subsequently found detectable levels of monocrotofos, imedacloprid, triazofos, atrazine, propanil, quinolfos and metribuzin in more than 23% of the water samples analyzed.

Graphical abstract.Figure optionsDownload full-size imageDownload high-quality image (85 K)Download as PowerPoint slideResearch highlights▶ Lyophilization with LC-MS/MS method for quantification of Ops in water was developed. ▶ The LOD & LOQ were observed in the range of 4.9–51 and 16.5–171 ngL−1, respectively. ▶ The CV (≥0.999) was less than 8.2% at the 0.1 ngL−1 with % recovery from 96% to103%. ▶ 23% water was contaminated with Ops pesticides. ▶ This method is simple, accurate, cost-effective, sensitive and time saving.