顶空气相色谱法测定丁腈橡胶中游离丙烯腈的含量

Determination of Free Acrylonitrile in Nitrile Rubber by Headspace Gas Chromatography

采用顶空气相色谱法测定了丁腈橡胶（NBR）中游离丙烯腈的含量,通过对溶剂、顶空温度和平衡时间的选择与优化,确定了分析条件;以外标法定量丙烯腈含量,建立了丙烯腈的标准工作曲线;考察了该方法的加标回收率、精密度及检出限。实验结果表明,以四氢萘为溶剂,在顶空温度100℃、平衡时间150 min的条件下可准确测定NBR中游离丙烯腈的含量。丙烯腈的标准工作曲线为y=1.28A（y为试样中丙烯腈含量,mg/kg;A为丙烯腈的峰面积）,当丙烯腈含量为3.3～1 000mg/kg时,线性相关系数为0.999 4;该方法的加标回收率为94.8%～98.6%,相对标准偏差小于3.0%（n=6）,方法的最低检出限为1.8 mg/kg。与ASTM D 5508—1994a（2009）方法相比,该方法操作简便,可大幅缩短分析时间。

A headspace gas chromatography method for the analysis of free acrylonitrile content in nitrile rubber was established. The effects of analysis conditions,namely solvent,headspace temperature and equilibrium time,on the analysis results were investigated. The standard working curve of acrylonitrile was established,which was y=1.28A（y：the content of acrylonitrile in sample,mg/kg;A：peak area of acrylonitrile）. Under the conditions of headspace temperature 100 ℃,equilibrium time 150 min and tetrahydronaphthalene as solvent,the free acrylonitrile content in nitrile rubber could be determined accurately. When the acrylonitrile content was in the range of 3.3-1 000 mg/kg,the correlation coefficient was 0.999 4. The adding standard recovery,relative standard deviation and detection limit of the method were 94.8%-98.6%,less than 3.0%（n=6） and 1.8 mg/kg,respectively. Compared with the ASTM D 5508—1994a（2009） method,the headspace gas chromatography is simple with short analytic time.