Selective and sensitive quantification of acetochlor and s-metolachlor in maize and soybean plant samples by Gas chromatography-tandem mass spectrometry
Abstract: Herbicide residue analysis has gained importance worldwide, mainly for food quality
control to minimize potentially adverse impacts on human health. A Gas chromatography-tandem
mass spectrometry (GC-MS) method for quantitative analysis of acetochlor and s-metolachlor in
maize and soybean straw has been developed, validated and applied to analyze the residues of
anilide herbicides. Straw material was dried, homogenized and extracted with a mixture of nhexane
and acetone by an accelerated solvent extraction method. Chromatographic separation
of the target analytes was performed on an Agilent 7832 GC equipped with a mass spectrometer
detector, a split-splitless injector and an HP-5 MS (5% phenylmethyl siloxane) capillary column
(30 m 0.25 mm 0.25 m). Under these parameters, the limit of detection (LOD) values were
0.2 ng g1 for acetochlor and 0.07 ng g1 for s-metolachlor, with average recoveries between 86%
and 119.7%. The method was validated for acetochlor and s-metolachlor in maize and soybean
straw at 0.5 and 0.01 mg kg 1. Furthermore, the final residues of the two herbicides in maize and
soybean straw were below the maximum residue limit (MRL) at harvest time. The proposed method
is suitable for routine analysis
