中文摘要：

含盐的复合溶剂萃取分离苯-环己烷等烃类混合物是一种获得高纯苯的有效方法.为使检测分离效果更为准确,选择合适的内标物尤为重要,依照国际标准,采用气相色谱内标法,讨论了对N,N-二甲基甲酰胺（DMF）＋硫氰酸钾（KSCN）复合溶剂萃取分离苯-环己烷各组分进行定量分析及内标物的选择问题.结果表明：正丁醇为内标物可行,该方法能够准确测量出各组分含量.三组分体系（苯-环己烷-DMF）和四组分体系（苯-环己烷-DMF-硫氰酸钾）中,苯、环己烷和DMF与内标物的峰面积比均与各标准品的质量百分比浓度呈良好的线性关系,变异系数不高于3.62%.测试结果的绝对误差小于2.44%,回收率、标准偏差分别在85.88%～110%和0.004%～1.13%之间.

英文摘要：

The examination of extractive separation of hydrocarbon mixtures,such as benzene-cyclohexane,with complex solvent,containing salt has been determined to be an effective method for analyzing high purity benzene.In order to detect the effects of separation more precisely,it is very important to select a suitable internal standard.According to international standards,an internal-standard gas chromatographic method was established to discuss the quantitative analysis of extracting benzene from cyclohexane utilizing N,N-dimethylformamide ＋ potassium thiocyanate complex solvent and how to select a suitable internal standard.Results illustrated that,n-butyl alcohol could be used as an internal standard;each component content could also be accurately detected using this method.In three-component system（benzene-cyclohexane-DMF） and four-component system（benzene-cyclohexane-DMF-potassium thiocyanate）,a good linear relationship of the mass percent of benzene,cyclohexane and DMF versus the peak area ratio of benzene to n-butyl alcohol,cyclohexane to n-butyl alcohol as well as DMF to n-butyl alcohol was observed with the coefficient of variation not more than 3.62%.The results of the experiments showed that the absolute error of the analyses was less than 2.44%.The recovery ranged from 85.88% to 110% and the standard deviation were in the range of 0.004%~1.13% respectively.