双波长双指示剂催化动力学光度法测定痕量亚硝酸根

Dual-wavelength and dual-indicator catalytic kinetic spectrophotometry for determination of trace nitrite

目的：建立测定痕量亚硝酸根的新方法。方法：在稀磷酸介质中，基于亚硝酸根对溴酸钾氧化甲基橙和甲基紫褪色的指示反应，通过测量500nm和600nm下，催化体系和非催化体系吸光度的变化，用双波长双指示剂催化动力学光度法测定痕量亚硝酸根。结果：在实验条件下，亚硝酸根浓度在0—0．60μg/ml之间存在线性关系（r=-0．999）。方法检出限为0．025μg/ml。结论：该法简单，灵敏度高，选择性好，可用于环境水样中痕量亚硝酸根的测定。

Objective： To develop a simple and sensitive new method for determination of trace nitrite in water samples. Methods：Nitrite was determined by dual - wavelength and dual - indicator catalytic kinetic spectrophotometric method which was based on the nitrite catalyzed oxidation of methyl violet and methyl orange by potassium bromate in the media of H3PO4. The absorbance of the catalytic and uncatalytic systems were measured at 500 nm and 600 nm. Results：Nitrite in the linear concentration range of 0 - 0. 60 μg/ml was determined with a detection limit of 0. 025μg/ml （ r = - 0. 999 ）. Conclusion： The method is simple and of high sensitivity and good selectivity.