化学发光法检测空气中NO_2研究

以0.2%的三乙醇胺水溶液作为二氧化氮吸收液,将空气中二氧化氮转化为亚硝酸盐,进而测出空气中二氧化氮的浓度。通过实验发现,进样方式、载流速度、硫酸浓度、溴酸钾浓度和酸性铬蓝K的浓度对该体系的发光强度都有影响,确定了体系的最优条件,建立了标准曲线,亚硝酸根的浓度在6.0×10-9～1.0×10-5mol/L范围内分段有很好的线性关系,检出限为8.5×10-11mol/L。对1.0×10-8mol/L和1.0×10-6mol/L的亚硝酸根进行11次平行测定,相对标准偏差分别为1.8%和2.2%。用该方法对氧化剂实验室空气中的二氧化氮含量进行了检测并进行标准加入和回收实验,回收率在95%～104%之间,该法可用于大气环境中的NO2测定。

Determination of NO_2 in Air by Chemiluminescence Detection

Nitrogen dioxide absorbed by 0.2% triethanolamine(TEA)solution and transformed quantatively to nitrite was detected by potassium bromate-Acid Chrome Blue K(ACBK)chemiluminescence system.The new method was developed to detect nitrogen dioxide in atmosphere,and the linear range for nitrite was 6.0×10-9～1.0×10-5 mol/L with a detection limit of 8.5×10-11mol/L,relative standard deviation(RSD)of 1.8% for 1.0×10-8mol/L nitrite solution and 2.2% for 1.0×10-6mol/L nitrite solution.The method developed was applied to determining nitrogen dioxide in atmosphere with satisfactory results.