A modified QuEChERS method for extracting different classes of emerging contaminants in soil.

Emerging contaminants (ECs) in soil pose concerns due to their potential health risks and toxicities. However, the pretreatment method for simultaneously extracting different classes of ECs was limited in soil. In this study, a rapid and robust pretreatment method based on a "Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS)" technology was developed for simultaneous extraction of 50 ECs, including 28 per- and polyfluoroalkyl substances (PFAS), 17 organophosphate esters (OPEs) and 5 diesters (di-OPEs) in soil. Acetonitrile and methanol with a mixture of magnesium sulfate and sodium chloride were selected for extraction while C18 was chosen for purification. The method displayed acceptable accuracy and precision with recoveries at 70 %-120 % and relative standard deviations (RSD) below 20 % in most cases. Except for 4:2 fluorotelomer sulfonate (4:2 FTS), the matrix effect values of other PFAS and di-OPEs ranged from 73 % to 123 %, while those of OPEs were within 30 %-93 %. With the addition of internal standards, the matrix effect of ECs can be well compensated except for tris (2-ethylhexyl) phosphate (TEHP) and 4:2 FTS. The method detection limits of PFAS, OPEs and di-OPEs were 0.01-0.21 ng/g, 0.01-3.96 ng/g and 0.03-0.16 ng/g, respectively. Overall, this pretreatment method allows extracting different classes of contaminants from soil with a high throughput, and might be used in conjunction with non-target screening in the future to give a more comprehensive perspective of compounds in complex matrix.