Ngamprasertsuk Sasitorn, Duenchay Paweenar, Dungchai Wijitar
Department of Chemistry, Faculty of Science, King Mongkut's University of Technology, Thonburi, Bangkok, 10140, Thailand.
Department of Industrial Engineering, Manufacturing Engineering, and Chemical Processes and Environment Engineering, Faculty of Engineering, Pathumwan Institute of Technology, 833, Rama 1Rd., Pathumwan, Bangkok, 10330, Thailand.
Anal Sci. 2025 Jun 2. doi: 10.1007/s44211-025-00800-1.
Phosphate ion (PO) monitoring in water sources is crucial due to its significant role in living systems and environmental impact, particularly in eutrophication. Conventional phosphate detection methods require sophisticated instruments and trained personnel. We report the development of a simple and cost-effective distance-based paper analytical device for phosphate ion detection. The device utilizes a complex of ferric ion (Fe), salicylic acid (SA), and polyethyleneimine (PEI) as the colorimetric indicator. Upon reaction with phosphate ions, Fe forms a complex with phosphate, replacing the Fe-SA complex, leading to a visible color change from orange to colorless. The phosphate concentration is quantified by the distance of color change, which can be observed with the naked eye. Under the optimal conditions, the linearity was found in the range 5 to 75 mg/L (R = 0.9954), and the naked-eye detection limit was found at 2 mg/L. Furthermore, by applying a preconcentration method, the detection limit can be improved tenfold, achieving an LOD of 0.2 mg/L. Our proposed device for water sample application was also validated with the standard molybdenum blue method. A paired t-test was performed to compare the results obtained from both methods, and the statistical analysis indicated no significant difference between the two methods (p > 0.05). The method validation studies also showed acceptable performance, with spiked sample recoveries ranging from 85.05% to 117.97%, within the internationally recognized acceptable criteria of 80-120%. This method offers an alternative approach for accurate, rapid, on-site phosphate monitoring.
由于磷酸根离子（PO）在生命系统中具有重要作用且对环境有影响，特别是在富营养化方面，因此对水源中的磷酸根离子进行监测至关重要。传统的磷酸盐检测方法需要精密仪器和专业人员。我们报告了一种用于磷酸根离子检测的基于距离的简单且经济高效的纸质分析装置的开发。该装置利用铁离子（Fe）、水杨酸（SA）和聚乙烯亚胺（PEI）的复合物作为比色指示剂。与磷酸根离子反应时，Fe与磷酸形成复合物，取代Fe-SA复合物，导致颜色从橙色变为无色的明显变化。通过颜色变化的距离对磷酸盐浓度进行定量，这可以用肉眼观察到。在最佳条件下，线性范围为5至75 mg/L（R = 0.9954），肉眼检测限为2 mg/L。此外，通过应用预浓缩方法，检测限可提高十倍，达到0.2 mg/L的LOD。我们提出的用于水样检测的装置也通过标准钼蓝法进行了验证。进行配对t检验以比较两种方法获得的结果，统计分析表明两种方法之间无显著差异（p > 0.05）。方法验证研究还显示出可接受的性能，加标样品回收率在85.05%至117.97%之间，符合国际认可的80 - 120%的可接受标准。该方法为准确、快速、现场磷酸盐监测提供了一种替代方法。
