11.Ｒapid determination of multiple herbicide residues insoils from the black soil region of northeast Chinaby QuEChEＲS combined with HPLC-MS / MS

Abstract:

A method based on the QuEChEＲS technique coupled with high-performance liquid chromatography-tandem mass spectrometry( HPLC-MS / MS) was developed for the simultaneous determination of five typical herbicides ( acetochlor，isoxaflutole，quizalofop-P-ethyl，atrazine，and fomesafen) in northeastern black soil． The procedure involved extracting 5 g of 60-mesh sieved soil samples with 5 mL of ace-tonitrile containing 2% acetic acid via vortex oscillation． The extract was dehydrated through salting-out phase separation using anhydrousmagnesium sulfate ( MgSO4 ) and sodium chloride ( NaCl) ，followed by centrifugation． The supernatant was further purified with anhy-drous MgSO4 and N-propyl ethylenediamine ( PSA) ，centrifuged again，and concentrated． The processed samples were analyzed byHPLC-MS / MS and quantified using an external standard method． The method demonstrated good linearity for all five herbicides within therange of 5 ～ 500 μg·kg － 1 ( Ｒ2 = 0． 995 7 ～ 0． 999 9) ，with instrument detection limits ( IDLs) of 0． 07 ～ 3． 06 μg·kg － 1 and method detection limits ( MDLs) of 1． 27 ～ 3． 51 μg·kg － 1 ，which were 20% ～ 60% lower than existing soil detection methods． The spikedrecoveries ranged from 86． 90% to 106． 50% ，with relative standard deviations ( ＲSDs) of 4． 15 ～ 10． 24% ． Compared to conventionalmethods，this approach reduced extraction time by over 75% and solvent consumption by more than 90% ，offering advantages such ashigh efficiency，sensitivity，low cost，and broad applicability to herbicides of varying polarities． It provides a robust technical solutionfor monitoring composite herbicide residues and assessing ecological risks in black soil regions．

Keywords: QuEChEＲS; HPLC-MS / MS; herbicides; combined residues