Abstract The design, optimization and evaluation of a micro paper-based analytical device (μPAD) for the simultaneous determination of fluoride and nitrite in real water samples was developed. In order to create hydrophilic and hydrophobic zones on the laboratory filter paper device, a wax ink printer was used. The μPAD has four reaction zones for each analyte where the respective colorimetric reactions took place using the SPADNS method and Griess method for fluoride and nitrite respectively. A Smartphone was used to capture the corresponding images which were then converted to the RGB colour space by the software ImageJ using a personal computer. Under the optimal conditions, the linear range was 0.23–2.26 mg L−1 for fluoride with limit of detection (LOD) and limit of quantification (LOQ) of 0.13 mg L−1 and 0.25 mg L−1. The working range for nitrite was 0.05–10.0 mg L−1 with LOD of 0.03 mg L−1 and LOQ 0.13 mg L−1. The μPAD was used to determine the analytes in water samples obtaining satisfactory results in both cases. The validation of fluoride determination was performed comparing the μPAD with the reference method and for nitrite determination, a recovery study was carried out. In both cases, the obtained results demonstrated a good agreement.

中文翻译：

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用于使用智能手机同时测定亚硝酸盐和氟化物的微型纸分析装置 (μPAD)

摘要 开发了一种用于同时测定实际水样中氟化物和亚硝酸盐的微型纸基分析装置（μPAD）的设计、优化和评价。为了在实验室滤纸装置上创建亲水和疏水区域，使用了蜡墨打印机。μPAD 对每种分析物有四个反应区，其中分别使用 SPADNS 方法和 Griess 方法对氟化物和亚硝酸盐进行比色反应。使用智能手机捕获相应的图像，然后使用个人计算机通过软件 ImageJ 将其转换为 RGB 色彩空间。在最佳条件下，氟化物的线性范围为 0.23–2.26 mg L-1，检测限 (LOD) 和定量限 (LOQ) 分别为 0.13 mg L-1 和 0.25 mg L-1。亚硝酸盐的工作范围为 0.05–10.0 mg L-1，LOD 为 0.03 mg L-1，LOQ 为 0.13 mg L-1。μPAD 用于测定水样中的分析物，在两种情况下均获得令人满意的结果。将 μPAD 与参考方法进行比较，对氟化物测定进行了验证，对于亚硝酸盐测定，进行了回收率研究。在这两种情况下，获得的结果都表现出良好的一致性。