基于顺序注射分析技术的总氮在线分析仪

针对环境监测领域,研制了一种基于顺序注射分析技术的总氮在线分析仪。该分析仪以注射泵为分析过程的液体驱动定量单元,以多通道选向阀为流路切换单元,以发光二极管和硅光电管为检测单元。在该分析平台上,含氮化合物在高温高压条件下经过硫酸钾氧化成硝酸根,硝酸根被还原为亚硝酸根后与N-(1-萘基)乙二胺盐酸盐生成偶氮染料,再由光电检测单元测定吸光度值,经计算得到总氮含量。与现有的总氮在线分析技术相比,该分析仪具有检测单元简单、生产成本低、测量精度高、试剂消耗和废液产生量少等优点,适合于环境监测等领域的长时间在线分析。

A Novel On-Line Total Nitrogen Analyzer Based on Sequential Injection Analysis Technology

A novel on-line total nitrogen analyzer based on sequential injection analysis technology has been developed. The analyzer mainly includes liquid delivery and quantification, stream switching and detector modules which include syringe pump, multichannel valve and light-emitting diode and silicon photodiode, respectively. The chemical principle is simple and intelligible. Firstly, nitrogen compounds are oxidized to nitrate by peroxodisulfate under the condition of high temperature and high pressure. Subsequently the hydrazine sulfate reduces the nitrate into the nitrite. Finally, the nitrite is reacted with 4-aminobenzene sulfonamide and N-(1-naphyl)-1,2-diaminoethane dihydrochloride to produce the aze dye. Moreover, the total nitrogen content can be worked out when absorbance values are obtained by the photometric measurement occurring in the detector module. Compare with other on-line total nitrogen analyzers, the analyzer has many advantages of simple detector module, low production cost, high accuracy, low maintenance and a little waste liquid. It is fit for long time on-line analysis and can deal with complex environment.