Rapid Analysis of Commonly Used Quaternary Ammonium Compounds in Soil and Sediment by Ultrasonic-assited Extraction
Quaternary ammonium compounds (QACs) are widely used as fungicides and surfactants in daily products and disinfection products,and as additives in industrial process. The QACs can be deposited and accumulated in soil after long-term discharge. In the present study,based on ultrasonic-assisted extraction-liquid chromatography-tandem mass spectrometry (UAE-LC-MS/MS) technique,a sensitive analytical method was developed for rapid analysis of 11 kinds of QACs,including 4 kinds of benzylalkyldimethylammonium compounds,4 kinds of alkyltrimethylammonium compounds,and 3 kinds of dialkyldimethylammonium compounds. The results showed that QACs in soil and sediment could be effectively extracted with 5%acetonitrile at 60℃. The 11 kinds of QACs were baseline-separated on a ZORBAX SB-C18 column coupled with ternary mobile phases (0.1%formic-water,0.1%formic-methanol and 0.1%formic-acetonitrile),showing excellent linear relationship in the range of 0.001-0.5μg/mL (R2>0.9776). The limits of detection were 0.01-0.31 ng/g (S/N=3). The recoveries of 11 kinds of QACs in soil samples were 78.7%-99.3% with relative standard deviations (RSDs)<12.9%,showing acceptable recoveries and repeatability. The results indicated that QACs could be extracted and cleaned-up within 4 h using this analytical method,with small volume of organic solvent consumed and less consumables materials.