Development of a Rapid Screening Method of Organic Pollutants in Soil by Liquid Chromatography/Mass Spectrometry (2) —Study of the Clean-up Method—

Abstract

A clean-up procedure has been developed for a rapid screening method used to determine hydrophilic organic pollutants in soil by liquid chromatography/mass spectrometry (LC/MS). We focused on the composition of the acetonitrile/water solvent mixture (50/50, v/v %), and performed the separation of acetonitrile by salting out with NaCl. Additionally, the acetonitrile solution was cleaned up using a column of ENVI-Carb C. In this study, we conducted recovery tests spiking with mixed standards of 23 pesticides (water solubility; 1.2-58000 mg L−1) for these procedures to optimize salting conditions and to evaluate the recovery rate performance. The optimal salting condition for 4 mL of acetonitrile/water (50/50, v/v %) was determined to be >0.6 g of NaCl. Furthermore, the recoveries of the targeted compound were 74–102 % and the relative standard deviations in the repeated experiments (n = 3) were within 6.6 %. We also performed recovery tests for all procedures of the screening including extraction The recoveries of all the compounds except for Thiram were 76–125 % and the relative standard deviations were within 7.0 % (n = 4). The total time required for preparing our screening was approximately 1 h. Therefore, the developed method is suitable for surveying hydrophilic organic pollutants in soil in emergencies, such as a chemical spills and earthquakes.