A low cost colorimetric microfluidic paper-based analytical device ( µ PAD) for the determination of nitrite in real samples with improved precision has been fabricated and its performance has been evaluated. The µ PAD was fabricated by laser cutting and patterning on the paper and the nitrite concentration measurement is based on the modified Griess assay. In this assay, tartaric acid was used as an antioxidant reagent to increase Griess reagent stability. A novel geometrical design was used to achieve better color gradient over µ PAD detection zone for improving the precision of the measurements. The results of measurement indicate that the fabricated device could successfully detect and quantify the nitrite concentration in real samples with the limit of detection of 15 μ M. The results are in good accordance with the results of spectrophotometry. The fabricated sensor has the potential to be applied for monitoring of the trace level of nitrite in drink...

中文翻译：

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比色法微流体纸基传感器，用于增强饮用水中亚硝酸盐的测定

制造了一种低成本的比色微流控纸基分析仪（µ PAD），用于提高真实样品中的亚硝酸盐含量，并对其性能进行了评估。µ PAD是通过在纸上进行激光切割和构图制成的，亚硝酸盐浓度的测量基于改进的Griess分析法。在该测定中，酒石酸用作抗氧化剂以增加格里斯试剂的稳定性。一种新颖的几何设计被用于在µ PAD检测区域上实现更好的颜色梯度，从而提高了测量精度。测量结果表明，该装置能够成功检测和定量真实样品中的亚硝酸盐浓度，检测极限为15μM。结果与分光光度法的结果非常吻合。制成的传感器有潜力应用于监测饮料中亚硝酸盐的痕量。