Determination of carbamate residues in crop samples by cholinesterase-based biosensors and chromatographic techniques

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• 作者：Nunes ; Gilvanda Silva ; Sklá ; dal ; Petr ; Yamanaka ; Hideko ; Barceló ; Damiá
• 关键词：Carbamates ; Acetylcholinesterases ; Crop samples ; Amperometric biosensors
• 刊名：Analytica Chimica Acta
• 出版年：1998
• 出版时间：April 24, 1998
• 年：1998
• 卷：362
• 期：1
• 页码：59-68
• 全文大小：113 K

文摘

An amperometric biosensor based on cholinesterase (ChE) has been used for the determination of selected carbamate insecticides in vegetable samples. The linear range of the biosensor for the N-methylcarbamates (aldicarb, carbaryl, carbofuran, methomyl and propoxur) varied from 5×10⁻⁵ to 50mgkg⁻¹. Limits of detection were calculated on the basis that the ChE enzymes were 10 % inhibited and varied, depending of the combination ChE (as acetyl- or butyrylcholinesterase) vs. inhibitor (pesticide), from 1×10⁻⁴ to 3.5mgkg⁻¹. The biosensor-based carbamate determination was compared to liquid chromatography/UV methods. Three vegetable samples were spiked with carbofuran and propoxur at 125μgkg⁻¹ followed by conventional procedures. Good correlations were observed for carbofuran in the vegetable extracts (79, 96 and 91 % recoveries for potato, carrot and sweet pepper, respectively), whereas for propoxur unsatisfactory results were obtained. Potato and carrot samples were spiked with 10, 50 and 125μgkg⁻¹ carbofuran, followed by direct determination by the amperometric biosensor. The fortified samples resulted in very high inhibition values, and recoveries were: 28, 34 and 99 % for potato, and 140, 90 and 101 % for carrot, respectively, at these three fortification levels.