Amoxicillin is an antibiotic that can accumulate in aquatic environments and lead to the development of resistant bacteria; thus, its determination is of great importance. In this study, a glassy carbon electrode modified with reduced graphene oxide and Nafion was used as a sensor in a square-wave voltammetry method for determination of amoxicillin in river water samples from Guarapuava city, Brazil. The method was validated, using parameters and statistical tools recommended by the validation guidelines, in the range of 1.8-5.4 μmol L-1 (r = 0.922 and R2 = 85.1%). The analytical curve was constructed using external standard calibration in pure electrolyte, since the matrix effect was not significant. Results of linear regression analysis, lack of fit test and analysis of the residual plots pointed that the linear regression was significant, without lack of fit of linear model and that the variances had homoscedastic distribution. Both coefficients of regression curve were significant and, thus, they were included in the regression equation: Response = 7.0 + 3.5CAMX. The limits of detection and quantification were 0.36 and 1.2 μmol L-1, respectively. The method was selective towards interferents such as humic acids and benzylpenicillin. The relative standard deviations for repeatability and intermediate precision were adequate according to the limits established in literature. The mean recoveries were statistically equal to those obtained through a comparative chromatography method, so, the accuracy of the method was also adequate. Therefore, the method can be applied to the voltammetric determination of amoxicillin in river water, affording reliable and consistent measurements.

中文翻译：

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伏安法测定河水中阿莫西林的建立与验证

阿莫西林是一种抗生素，可以在水生环境中积累并导致耐药细菌的产生；因此，它的决心非常重要。在这项研究中，使用还原氧化石墨烯和 Nafion 改性的玻碳电极作为传感器，在方波伏安法中测定巴西瓜拉普瓦市河水样品中的阿莫西林。该方法使用验证指南推荐的参数和统计工具进行验证，范围为 1.8-5.4 μmol L-1（r = 0.922 和 R2 = 85.1%）。由于基质效应不显着，因此在纯电解质中使用外标校准构建了分析曲线。线性回归分析的结果，缺乏拟合检验和残差图的分析表明线性回归是显着的，没有缺乏线性模型的拟合，并且方差具有同方差分布。回归曲线的两个系数都很显着，因此，它们被包含在回归方程中：响应 = 7.0 + 3.5CAMX。检测限和定量限分别为 0.36 和 1.2 μmol L-1。该方法对干扰物如腐殖酸和苄青霉素具有选择性。根据文献中建立的限制，重复性和中间精密度的相对标准偏差是足够的。平均回收率在统计上与通过比较色谱法获得的回收率相等，因此该方法的准确度也足够。因此，该方法可用于河水中阿莫西林的伏安测定，提供可靠且一致的测量结果。