Integrated Science and Technology Research Center, Faculty of Technology and Environment, Prince of Songkla University, Phuket Campus, Kathu, Phuket 83120, Thailand.
Integrated Science and Technology Research Center, Faculty of Technology and Environment, Prince of Songkla University, Phuket Campus, Kathu, Phuket 83120, Thailand.
Spectrochim Acta A Mol Biomol Spectrosc. 2020 Dec 15;243:118812. doi: 10.1016/j.saa.2020.118812. Epub 2020 Aug 11.
Nowadays, nitrate (NO) and nitrite (NO) in aquatic ecosystems have increased due to various anthropogenic activities leading to deterioration of the ecosystem and can accelerate eutrophication. A Griess reagent-doped hydrogel test kit and a zinc powder-doped starch film were thus developed for on-site quantitative analysis of nitrate and nitrite. A clear colorless hydrogel tablet (diameter 1.5 cm 2 mm thickness) turned pink-violet after reacting with a standard solution of nitrite while the gray zinc-doped starch film (8.36 μm thickness) fabricated on the inner lid of small plastic tube was used for the in-tube reduction of nitrate to be nitrite. The use of this film followed by nitrite testing using the hydrogel tablet was used as a nitrate test. Both the materials developed were used in conjunction with digital image colorimetry (DIC) using smartphone application for on-site quantitative analysis of nitrite and nitrate. Good linearity (R > 0.99) ranges of 0.05 to 5 mg L for nitrite and 1 to 50 mg L for nitrate were obtained and detection limits of 50 μg L for nitrite and 0.32 mg L for nitrate were achieved. Good accuracy was obtained in terms of a relative error in a range of 0.75 to 2.68% with inter-day precision in a range of 0.20 to 0.50%RSD (n = 3). Quantitative analysis of nitrate and nitrite in 10 seawater samples taken in Phuket was in good agreement with the standard method (95% confidence level). Since the method developed employs test kits synthesized using biodegradable polymers and DIC using a smartphone application, it will allow the rapid on-site quantitative detection of nitrate and nitrite in a more convenient and environmentally friendly system.
如今，由于各种人为活动，水生生态系统中的硝酸盐（NO）和亚硝酸盐（NO）增加，导致生态系统恶化，并加速富营养化。因此，开发了一种含有硝酸根试剂的水凝胶测试试剂盒和一种锌粉掺杂的淀粉薄膜，用于现场定量分析硝酸盐和亚硝酸盐。一个直径为 1.5 厘米、厚度为 2 毫米的无色透明水凝胶片剂在与亚硝酸盐标准溶液反应后变为粉红色-紫色，而在小塑料管内盖上制造的灰色锌掺杂淀粉薄膜（8.36 微米厚）则用于将硝酸盐还原为亚硝酸盐。使用该薄膜后，使用水凝胶片剂进行亚硝酸盐测试，可作为硝酸盐测试。这两种材料都与智能手机应用的数字图像比色法（DIC）一起使用，用于现场定量分析亚硝酸盐和硝酸盐。亚硝酸盐的线性范围为 0.05 至 5mg/L，R>0.99，硝酸盐的线性范围为 1 至 50mg/L，亚硝酸盐的检测限为 50μg/L，硝酸盐的检测限为 0.32mg/L。在相对误差为 0.75%至 2.68%的范围内，获得了良好的准确性，日内精密度在 0.20%至 0.50%RSD（n=3）的范围内。用标准方法对取自普吉岛的 10 个海水样本中的硝酸盐和亚硝酸盐进行定量分析，结果吻合良好（置信水平为 95%）。由于所开发的方法采用可生物降解聚合物合成的测试试剂盒和智能手机应用的 DIC，因此它将允许在更方便和环保的系统中快速现场定量检测硝酸盐和亚硝酸盐。
