2019 Volume 68 Issue 11 Pages 885-895
A simultaneous determination method for new systematic insecticides and their metabolites in river water was developed by liquid chromatography tandem mass spectrometry (LC-MS/MS). The pretreatment method using solid-phase extraction (SPE) combined with clean up by a graphited carbon cartridge were optimized in this study, and the developed method was applied to a survey of river water. From the results of comparing SPE cartridges and eluate solutions, an Oasis HLB plus cartridge with 5 mL of methanol as an eluate were suitable for the method. To improve the recovery rates of 6-chloronicotinic acid and N-(6-chloro-3-pyridylmethyl)-N-ethyl-N’-methyl formamidine (CPMF), the sample pH was adjusted for 4.75 before loading SPE cartridge. The recovery rates of analytes using developed method ranged from 69-130 % (RSD: 1.2-15 %), except for 6-chloronicotinic acid. The linearity of all the analytes was greater than 0.99. The method detection limits (MDL) ranged from 0.2 to 4 ng L−1. Water samples collected at 6 different sites in a river located in Akita pref. were analyzed by the developed method. Dinotefuran, thiamethoxam and clothianidin were detected in the range of 3-53 ng L−1.
