PDF(Pubmed)
Abstract：
There are many works associating the presence of nitrate in water and the occurrence of cancer in humans. The most common method for quantifying nitrate in water is based on the use of toxic cadmium as a reductant. In this work, a new approach was developed for the quantification of nitrate in bottled water with indirect spectrophotometry using Zn0 as a reductant. Nitrate is reduced to nitrite using Zn0 in a buffered medium (acetate/acetic acid) and quantified with visible spectrophotometry using the Griess reaction between sulfanilamide and N-(1-naphthyl)-ethylenediamine. The influence of pH, buffer solution (constitution and concentration), Zn0 (mass and granulometry), and agitation time on the efficiency of nitrite generation was evaluated. The optimal conditions were an acetate-acetic acid buffer solution with a concentration and pH of 0.75 mol L-1 and 6.00, respectively, and a Zn0 particle size of 20 MESH and Zn0 mass of 300 mg. The limits of detection and quantification (LoD and LoQ) were 0.024 and 0.08 mg L-1, respectively. The method\'s accuracy and precision were evaluated using the analysis of commercial bottled water. In conclusion, the use of Zn0 instead of cadmium provided a green method with excellent LoD/LoQ. Further, the method proved to be simple and easy to apply during outdoor analysis.
摘要：
有许多作品将水中硝酸盐的存在与人类癌症的发生联系起来。定量水中硝酸盐的最常用方法是使用有毒的镉作为还原剂。在这项工作中,开发了一种使用Zn0作为还原剂的间接分光光度法定量瓶装水中硝酸盐的新方法。在缓冲介质（乙酸盐/乙酸）中使用Zn0将硝酸盐还原为亚硝酸盐，并使用可见分光光度法使用磺胺和N-（1-萘基）-乙二胺之间的Griess反应进行定量。pH的影响，缓冲溶液（组成和浓度），Zn0(质量和粒度)，并评价了搅拌时间对亚硝酸盐生成效率的影响。最佳条件为乙酸-乙酸缓冲溶液，浓度和pH分别为0.75molL-1和6.00，和20个MESH的Zn0粒径和300mg的Zn0质量。检出限和定量限（LoD和LoQ）分别为0.024和0.08mgL-1。方法的准确度和精密度是通过分析商业瓶装水来评估的。总之,使用Zn0代替镉提供了具有优异LoD/LoQ的绿色方法。Further,证明该方法简单，易于在户外分析中应用。
