Development of a fast and sensitive method for measuring multiple neonicotinoid insecticide residues in soil and the application in parks and residential areas.

Abstract A method for simultaneous measure of nine neonicotinoid insecticide residues in soil was developed by using liquid chromatography-tandem mass spectrometry (LC-MS/MS) coupled with a quick pretreatment procedure. The soil was extracted with a mixture of acetonitrile and dichloromethane (1:2, v:v) and cleaned up with Primary Secondary Amine (PSA). Matrix-matched standards were prepared to eliminate the interference of the matrix. The LC–MS/MS conditions were optimized to separate the nine neonicotinoids within 6.7 min, and the obtained limits of detection (LODs) and limits of quantification (LOQs) ranged from 0.01 to 0.84 ng g −1 and 0.05–2.79 ng g −1 , respectively. Recoveries of the studied neonicotinoids (except for nitenpyram) ranged from 79.41 to 100.20% with relative standard deviations (RSDs) less than 10% at spiked levels of 5 ng mL −1 , 100 ng mL −1 and 500 ng mL −1 , and RSDs for the interday and intraday method repeatability were less than 9%. The method was applied to measure neonicotinoid residues in soil samples collected from parks (n = 35) and residential areas (n = 33) in Tianjin, China. Seven neonicotinoids were detected, with imidacloprid being the most frequently detected one, followed by acetamiprid and thiamethoxam. The total concentrations of neonicotinoids in soil ranged from 0.27 to 230.76 ng g −1 in parks and 0.23–132.66 ng g −1 in residential areas.