顶空箭形固相微萃取–气相色谱质谱法分析烃源岩和稠油中的金刚烷类化合物

Headspace-solid phase microextraction arrow technique combined with gas chromatography-mass spectrometry analysis of diamondoids in source rocks and heavy oils

采用顶空箭型固相微萃取–气相色谱质谱联用技术(HS-SPME Arrow-GC/MS)直接检测分析烃源岩粉末样品和稠油中的单金刚烷类和双金刚烷类化合物,考察并优化了影响萃取效率的萃取纤维头类型、萃取温度、萃取时间和解析时间等关键因素。对于小于80目的烃源岩样品,推荐最优HS-SPME Arrow实验条件为:使用250μm PDMS箭形固相微萃取头, 120℃下萃取20 min, 260℃下解析8 min。对于稠油,当使用250μm PDMS萃取纤维头、萃取温度为120~150℃、萃取时间为15~20 min、解析时间为3~8 min时,稠油中的单金刚烷类和双金刚烷类化合物都能取得较理想的质谱响应。该方法实现了对烃源岩粉末和稠油中金刚烷类化合物的直接分析,灵敏度高,检出限低(0.004~0.977 ng/g),重现性好,测量峰面积和比值参数的相对标准偏差分别小于20%和5%,避免了复杂的前处理过程,是一种快捷可靠的分析方法。

The monoadamantane and diamantine compounds in the source rock powder samples were directly analyzed by the headspace-solid phase microextraction arrow technique combined with gas chromatography-mass spectrometry(HS-SPME Arrow-GC/MS).The key factors affecting the extraction efficiency,including the SPME Arrow fibre coating,extraction temperature,exposure time,and desorption time,were investigated and optimized.For source rock powders less than 80 mesh,the optimal HS-SPME Arrow experimental conditions are recommended as follows:PDMS with 250μm coating thickness fibre(250μm PDMS),20 min of extraction at 120℃,and 8 min desorption at 260℃.The experimental conditions for detecting diamondoids in heavy oils using the HS-SPME Arrow were also investigated and optimized.When using a 250μm PDMS,extracting at temperature of 120℃to 150℃for a duration of 15 min to 20 min,and desorbing for 3 min to 8 min,higher extraction efficiency for monoadamantanes and diamantanes in heavy oil can be achieved,resulting in ideal mass spectrometry responses.The HS-SPME Arrow-GC/MS method enables the direct analysis of diamondoids in powdered source rock samples and heavy oils,with high sensitivity,low detection limits(0.004 ng/g to 0.977 ng/g),and good reproducibility.The relative standard deviations(RSD)of the measured peak area and ratio parameters for diamondoid compounds are generally less than 20%and 5%,respectively.This method avoids complex pretreatment processes and is a fast and reliable analytical method.