挥发性有机毒物测定标准曲线斜率值及斜率指数K值的应用

Application of standard curve slope value and slope index K value in determination of volatile organic compounds

目的探讨气相色谱测定空气中有机毒物标准曲线斜率值及斜率指数K值的应用。方法经过长期试验,总结32种工作场所常见毒物色谱标准物标准曲线回归方程的斜率b值,观察色谱仪条件不变和使用同一支色谱柱时不同毒物色谱标准物所产生斜率b值的大小,计算斜率特性指数K值。结果用气相色谱非极性毛细管DB-1柱做工作场所常见毒物色谱标准物标准曲线,保持色谱条件一直不变。既使浓度相同,不同的化学物质由于其分子组成和分子结构的差异,导致在FID检测器出峰积分面积的不同。把一种色谱标准物标线的b值与甲苯标线的b值之比值作为斜率指数K值。四氯化碳的斜率指数K值最小,为0.050 3,二甲苯的斜率指数K值最大,为1.07,其余30种毒物色谱标准物标准曲线的斜率指数K值在两者之间。结论同一种毒物标准物的K值,在一定色谱条件下,是一个固定值,是一种毒物标准物的特征参数。利用这种特征参数的规律,可以判断标准曲线做的是否准确。做混标时,可以判断哪个色谱峰代表的是哪种标准物。

[Objective]To explore the application of standard curve slope value and slope index K value in determination of volatile organic compounds in air by gas chromatography.[Methods]By the long term test,slope standard curve slope（b value）of chromatographic standard substances of 32 kinds of volatile organic compounds in workplace were summarized,to observe the b value of different standard substances in same chromatographic column under identical condition of chromatograph,and calculate the slope characteristic index K value.[Results]Non-polar capillary DB-1 column was adopted in the study,and the chromatography conditions were identical. In the same concentration,different chemicals had different peak area in the FID detector due to differences in the molecular composition and molecular structure. The ratio of b value of a chromatographic standard substance to b value of toluene was regarded as the slope K value. K value of carbon tetrachloride was the lowest（0.050 3）while that of xylene was the highest（1.07）,and K values of rest 30 volatile organic compounds were between the two.[Conclusion]K value of standard substance of a toxicant is a fixed value under the identical condition of chromatograph,and it is a characteristic parameter. The laws of characteristic parameter can be used to judge the accuracy of the standard curve,and the standard substance can be identified by the chromatographic peak in the mixed determination.