二阶梯度升温热解吸法测定空气中的微量丙烯腈和乙腈

采用气体采样泵将空气样品的丙烯腈和乙腈吸附到吸附管中,用二阶梯度升温将吸附管中的被测物质解吸到冷阱中,再快速对冷阱升温,将冷阱中的被测物质解吸进入色谱柱进行分离,用气相色谱氢火焰检测器检测空气中的微量丙烯腈和乙腈。丙烯腈、乙腈的色谱峰面积与吸附质量的线性相关系数均大于0.995。该法对实际空气样品中丙烯腈的检出限为5μg/m3,乙腈的检出限为10μg/m3,加标回收率均大于90%。

DETERMINATION OF TRACE ACRYLONITRILE AND ACETONITRILE IN AIR BY TWO-STAGE THERMAL DESORPTION

Acrylonitrile and acetonitrile in air were drawn to the tenax tube by air sample pump. Analytes were desorbed to the cold trap by two - stage thermal desorption, then the cold trap was heated quickly. Analytes in the cold trap were heated and purged simultaneously to the GC column and determined by FID detector. The linear calibration curves of acrylonitrile and acetonitrile were obtained with correlation coefficient exceeding 0.995. The low detection limits of acrylonitrile and acetonitrile in air were 5 ug/m^3 and 10ug/m^3, respectively. The average recoveries of acrylonitrile and acetonitrile were more than 90%.