浊点萃取-分光光度法测定痕量NO2-

建立了浊点萃取-分光光度法测定痕量NO2-根的方法.以对氨基苯磺酸和α-萘胺为络合剂,非离子型表面活性剂TritonX-100为萃取剂,富集、分离水样中痕量NO2-,采用可见吸收光谱法进行检测.研究了溶液的酸度、试剂用量、平衡时间、平衡温度、干扰离子对浊点萃取效果的影响,并得到最佳实验条件:5％的TritonX-100用量2.0mL、平衡温度85℃、平衡时间10min、对氨基苯磺酸和α-萘胺均为0.3mL、0.1mol/LH2SO4溶液0.5mL.在最佳实验条件下,对氨基苯磺酸、α-萘胺和NO2-生成的络合物被萃取到TritonX-100表面活性剂相并与水相分开.该方法适用于环境水样中痕量NO2-的测定.

Determination of trace nitrite ion by spectrophotometry with cloud point extraction

A new method for the determination of trace nitrite ion by spectrometry after cloud point extraction was proposed.With sulfanilic acid and α-naphthylamine as complexing agents,nonionic surfactant TritonX-100 as an extractant,enrichment,separation and detection of trace NO2-was achieved by using visible absorption spectroscopy.The effects of solution acidity,reagent dosage,balance time,equilibrium temperature,interfering ions on the effect of cloud point extraction were discussed,and the optimal experimental conditions were as follows: 2.0 mL of 5% TritonX-100,85℃,10 min,0.3 mL of sulfanilic acid and α-naphthylamine,0.5 mL of 0.1 mol/L sulfuric acid solution.Under the optimum conditions,the complex formed by sulfanilic acid,α-naphthylamine and NO2-was extracted into the surfactant TritonX-100 phase which was separated from water phase.The method is simple,accurate,efficient,and it has high selectivity,high sensitivity characteristics of determining trace NO2-in water samples.