液相色谱系统峰对煤基油品烃族组成的影响

Effect of system peaks in liquid chromatography on hydrocarbons of coal-derived oil

为考察及规避液相色谱系统峰对煤基油品烃族组成的测定影响,运用高效液相色谱正相模式分析煤基油品的烃族组成,固定相选用NH_2基柱,流动相采用正庚烷试剂,利用示差折光检测器考察了煤基油品各烃族标准物质的保留时间及响应因子,对标准物质掺混物及煤基中间馏分油进行了分析并验证结果的可靠性。结果表明,受系统倒峰的干扰,采用单组分的饱和烃标准物质进样分析,饱和烃出峰位置易出现异形峰;而采用混合饱和烃标准物质进样分析,利用不同标准物质保留时间微小的差异可有效规避异形峰,再考虑其标准物质响应因子的差异,可使测试结果更趋于真值。以煤基中间馏分油测试为例,试验准确度回收率在94%~105%,液相色谱结果与质谱法结果对比,饱和烃与总芳烃相对偏差均不超过5%。

To investigate and avoid the influence of liquid chromatographic system peaks on the determination of hydrocarbon group composition of coal based oil products,an effective method was developed by positive phase high performance liquid chromatography（ HPLC）.Taking NH_2 column as stationary and n-hexane as mobile phase,the separation process was detected by a differential refractive index detector.The response factor and retention time of each group compound was determined by standard substances,and the reliability of experimental results was analyzed.The results show that,after using single standard substance of saturated hydrocarbon,special-shaped peak is appeared due to the interference of system peak. Taking advantage of hybrid standard substance of saturated hydrocarbon can effectively avoid the abnormal peaks according to the small difference of retention time of different standard materials.Besides,considering the differences in the response factor of standard material will make the test results more accurate.For coal-derived middle distillate,the experimental accuracy rate is 94%-105%,and the relative deviation of saturated hydrocarbon and aromatic hydrocarbons is below 5% compared with the GC-MS results.