石油样品中金刚烷类化合物的定量分析新方法

A novel method for quantitative analysis of diamondoids in petroleum samples

在用全二维气相色谱—飞行时间质谱定性石油样品中的金刚烷系列化合物基础上,建立了一套包括前处理方法在内的用全二维气相色谱—氢火焰离子化检测器定量分析石油样品中金刚烷类化合物的新方法。该方法利用全二维气相色谱正交分离的特点,使得常规的金刚烷系列化合物在色谱条件下就能很好地分离,实现了该类化合物的色谱定量分析。为减少前处理过程中低碳数金刚烷类化合物的挥发损失,新方法中对现有的石油样品饱和烃馏分的分离方法进行改进,建立了用小柱法分离收集饱和烃前馏分的方法,具有所需样品量少、分析时间短、实验耗材少的特点,金刚烷回收率满足色谱定量分析的需要。与传统的色谱—质谱定量方法相比,全二维色谱定量方法分离度高,重复性好,对内标物质要求低,7次实验的相对标准偏差小于5%,满足复杂体系的分析要求。

A new method for the quantitative analysis of diamondoid hydrocarbons in petroleum geological samples was established using comprehensive two-dimensional gas chromatography-flame ionization detector (GC×GC-FID). The process included the pretreatment of sample followed by the qualitative analysis of diamondoid hydrocarbons using two-dimensional gas chromatography with time-of-flight mass spectrometry (GC×GC-TOFMS). The diamondoid hydrocarbons could be well separated using the orthogonal separation characteristics of GC×GC, The original separation method of saturated hydrocarbon fraction in petroleum samples was improved in this study in order to reduce the loss of low-carbon diamondoid hydrocarbons in the pretreatment process. A new pretreatment method for saturated hydrocarbon by small column chromatography was established. There were many advantages such as lower sample costs, short analysis time and little consumption of reagents. The recovery of diamondoid hydrocarbons was satisfied for chromatography quantitative analysis. Compared to the traditional internal standard semi-quantitative method by gas chromatography-mass spectrometry (GC-MS), this method had high resolution and lower requirements for internal standards. The quantitative results of diamondoids could be obtained using only one certified reference material of deuterated adamantane. Moreover, the repeatability was good. The relative standard deviation (RSD, n =7) was less than 5%, which could meet the analytical requirements of a complicated system.