Development of an analytical method for determination of total ethofumesate residues in foods by gas chromatography-tandem mass spectrometry. (30th May 2020)

• Record Type: Journal Article
• Authors: Saito-Shida, Shizuka; Kashiwabara, Nao; Shiono, Kouji; Nemoto, Satoru; Akiyama, Hiroshi
• Is Part Of: Food chemistry. Volume 313(2020)
• Publication Date: 2020-05-30
• Subjects: Ethofumesate -- 2-Keto-ethofumesate -- Open-ring-2-keto-ethofumesate -- Hydrolysis -- GC–MS/MS; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2019.126132
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: A GC–MS/MS method was developed to determine total ethofumesate (ET) residues. Open-ring-2-keto-ET and 2-keto-ET gave an equilibrium mixture upon heating in HCl. Open-ring-2-keto-ET was converted to 2-keto-ET by reaction with acetic anhydride. The developed method was validated using garlic, onion, and sugar beet samples. The method showed satisfactory recoveries (94–113%) with minimal matrix effects. Abstract: Analytical method was developed for determining the total residue of ethofumesate (ET) herbicide using GC–MS/MS. The ET residues were analyzed as a sum of ET, 2-keto-ethofumesate (KET), and open-ring-2-keto-ethofumesate (OKET) and its conjugate. The extracted samples were partitioned with hexane and NaOH solution. For ET analysis, the hexane layer was cleaned up by a silica gel cartridge prior to GC–MS/MS analysis. For the analyses of the metabolites, the aqueous layer was heated with HCl to hydrolyze the conjugates, thereafter, heated in acetic anhydride to convert OKET to KET, and cleaned up by a silica gel cartridge prior to GC– MS/MS analysis. The method was validated for ET, KET, and OKET in garlic, onion, and sugar beet at 0.3 and 0.01 mg/kg. The recoveries were 94–113%, with relative standard deviations of <6%. The limits of detection were 0.0005 mg/kg for all analytes. The proposed method is suitable for regulatory analysis.