Abstract In this work we have fabricated a glutathione-S-transferase based amperometric biosensor for pesticides by immobilizing the enzyme on platinum electrode using graphene oxide-gelatin matrix, evaluated various biosensor parameters, applied the same for detection and quantification of four different classes of pesticides and validated the biosensor results with GC–MS analysis. The enzyme immobilization was confirmed through scanning electron microscopy, electrochemical impedance spectroscopy, cyclic voltammetry and chronoamperometry. The apparent Michaelis-Menten constant for the immobilized glutathione-S-transferase in the said matrix was found to be 0.083 mmol L−1 and 0.15 mmol L−1 respectively for glutathione and 1-Chloro-2,4-dinitrobenzene. Substrate specificity found to be 2.56 × 107 s−1 M−1 for glutathione and 2.15 × 107 s−1 M−1 for 1-Chloro-2,4-dinitrobenzene. Pesticide analysis was done in 25% methanol solution. The biosensor is a promising new tool for pesticide analysis as it can be applied for analysis of a broad spectrum of pesticides covering at least six different classes namely - benzamidazole, organochlorine, organothiophosphate, organocarbamate, polyphenol and pyrethroid.

中文翻译：

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基于固定在氧化石墨烯-明胶基质上的谷胱甘肽S-转移酶的广谱电流法农药生物传感器

摘要 在这项工作中，我们通过使用氧化石墨烯-明胶基质将酶固定在铂电极上，制造了一种基于谷胱甘肽-S-转移酶的农药安培生物传感器，评估了各种生物传感器参数，并将其应用于四种不同类别农药的检测和定量。并通过 GC-MS 分析验证了生物传感器的结果。通过扫描电子显微镜、电化学阻抗谱、循环伏安法和计时电流法证实了酶的固定化。发现所述基质中固定化谷胱甘肽-S-转移酶的表观Michaelis-Menten常数对于谷胱甘肽和1-氯-2,4-二硝基苯分别为0.083 mmol L-1和0.15 mmol L-1。谷胱甘肽和 2 的底物特异性为 2.56 × 107 s-1 M-1。15 × 107 s−1 M−1 对于 1-Chloro-2,4-dinitrobenzo。农药分析在 25% 甲醇溶液中进行。生物传感器是一种很有前途的农药分析新工具，因为它可以用于分析涵盖至少六种不同类别的广谱农药，即苯并咪唑、有机氯、有机硫代磷酸酯、有机氨基甲酸酯、多酚和拟除虫菊酯。