二次热解析-气相色谱法测定含氰废气中的氰化物

Determination of cyanides in CN-containing waste gas by two-time thermal desorption/gas chromatography

建立了以Tenax-TA吸附管为吸附剂,采用二次热解析-气相色谱联用技术测定相关含氰废气处理装置试样中丙烯腈、乙腈含量的方法,通过对热解析和色谱条件进行优化,使用标准试样测定了线性范围和工作曲线,考察了方法的精密度和准确度,并采用该方法对含氰废气中的丙烯腈、乙腈进行了测定。实验结果表明,丙烯腈、乙腈的质量浓度在各自配制的质量浓度范围内呈现良好的线性关系,相关系数为0.999 9。标样回收率在99%～104%之间,6次重复测定的相对标准偏差均小于3%,两种物质的热解析效率均高于98%,丙烯腈检出限为3.12×10^(-4) mg/m^3。该方法具有良好的准确性、精密度和灵敏度,能很好地适用于含氰废气检测。

A method of determining acrylonitrile and acetonitrile contents in CN-containing waste gas was developed by a two-time thermal desorption/gas chromatography combined technique using Tenax-TA adsorption tube as adsorbent. The thermal desorption/gas chromatography conditions were optimized,and the precision and accuracy of this method were investigated by determining the linear range and working curve using standard samples. The method was applied to the determination of acrylonitrile and acetonitrile contents in the CN-containing waste gas. The experimental results showed that the mass concentrations of acrylonitrile and acetonitrile exhibited a good linear relationship within each formulaed mass concentration range,with correlation coefficients of 0.999 9. The recoveries of standards samples were from 99% to 104%,and the relative standard deviations of six repeated measurements are within 3%. Thermal desorption efficiency of the two components were above 98%,and the detection limit of acrylonitrile was 3.12×10-4 mg/m3. The method has good accuracy, precision and sensitivity,and is suitable for the detection of CN-containing waste gas.