Determination of multi-class herbicides in soil by liquid-solid extraction coupled with headspace solid phase microextraction method

• Published in: Journal of the Serbian Chemical Society 2016, Vol.81 (8), p.923-934
• Main Authors: Djurovic-Pejcev, Rada, Djordjevic, Tijana, Bursic, Vojislava
• Format: Article
• Language: English
• Subjects: gas chromatography mass spectrometry; multiresidue method; pesticides; soil matrix
• ISSN: 0352-5139; 1820-7421
• DOI: 10.2298/JSC151123044D

A method is described for simultaneous determination of five herbicides (metribuzin, acetochlor, clomazone, oxyfluorfen and dimethenamid) belonging to different pesticides groups in soil samples. Developed headspace solid phase microextraction method (HS-SPME) in combination with liquid-solid sample preparation (LS) was optimized and applied in the analysis of some agricultural samples. Optimization of microextraction conditions, such as temperature, extraction time and sodium chloride (NaCl) content was perfor-med using 100 ?m polydimethyl-siloxane (PDMS) fiber. The extraction effi-ciencies of methanol, methanol:acetone=1:1 and methanol:acetone:hexane= =2:2:1 and the optimum number of extraction steps during the sample prepa-ration, were tested, as well. Gas chromatography-mass spectrometry (GC-MS) was used for detection and quantification, obtaining relative standard deviation (RSD) below 13%, and recovery values higher than 83% for multiple analyses of soil samples fortified at 30 ?g kg-1 of each herbicide. Limits of detection (LOD) were less than 1.2 ?g kg-1 for all the studied herbicides.