Gu X, Zhou T, Qi D
Capital Normal University, Beijing 100037, China.
Talanta. 1996 Feb;43(2):169-75. doi: 10.1016/0039-9140(95)01686-4.
A simple and rapid preconcentration technique, based on collecting trace nitrite on a membrane filter and dissolving the membrane filter in an organic solvent, has been applied to its spectrophotometric determination in water. At pH 2.0, nitrous acid diazotizes with p-aminoacetophenone. which is then coupled with N-(1-naphthyl)ethylenediamine, at the same pH. The azo dye formed is collected on a 0.45 urn nitrocellulose filter at pH 4.7 as its ion associate with dodecyl sulfate. The ion associate and filter are dissolved in a small volume of 2-methoxyethanol (methylcellosolve), and acidized with 0.05 ml of 2 M hydrochloric acid and the absorbance of the resulting solution is measured at 555 nm against a reagent blank. Detection limits better than O.1 mug/dm(-3) as NO(2)(-) can be achieved. The ions normally present in water do not interfere when sodium metaphosphate is added as a masking agent. The proposed method has been applied to the analysis of water samples from several sources, the recoveries of the nitrite added to the samples are quantitative, and results found are satisfactory.
一种基于在膜滤器上收集痕量亚硝酸盐并将膜滤器溶解于有机溶剂中的简单快速预富集技术，已应用于水中亚硝酸盐的分光光度测定。在pH 2.0时，亚硝酸与对氨基苯乙酮重氮化，然后在相同pH下与N-（1-萘基）乙二胺偶合。形成的偶氮染料在pH 4.7时作为其与十二烷基硫酸盐的离子缔合物收集在0.45μm硝酸纤维素滤器上。将离子缔合物和滤器溶解于少量2-甲氧基乙醇（甲基溶纤剂）中，并用0.05 ml 2 M盐酸酸化，然后以试剂空白为参比，在555 nm处测量所得溶液的吸光度。可以实现优于0.1μg/dm(-3)（以NO(2)(-)计）的检测限。当加入偏磷酸钠作为掩蔽剂时，水中通常存在的离子不会产生干扰。所提出的方法已应用于多种来源水样的分析，样品中添加的亚硝酸盐回收率是定量的，且所得结果令人满意。
