气相色谱法测定石油蜡中正构烷烃含量的不确定度评定  

Uncertainty Evaluation for Determination of n-Paraffin Content in Petroleum Wax by Gas Chromatography

作　　者：郝逍瑶 韩博 凌凤香 HAO Xiao-yao;HAN Bo;LING Feng-xiang(Sinopec(Dalian)Research Institute of Petroleum and Petrochemicals Co.,Ltd.,Dalian Liaoning 1160451,China)

机构地区：[1]中石化(大连)石油化工研究院有限公司,辽宁大连116045

出　　处：《当代化工》2023年第6期1507-1512,共6页Contemporary Chemical Industry

摘　　要：选用《石油蜡正构烷烃和非正构烷烃含量及碳数分布的测定气相色谱法》(NB/SH/T 0653—2021)石化行业标准规范,以n-C_(16)为内标,使用氢火焰离子化检测器气相色谱仪,检测石油蜡中所含正构烷烃质量分数。对完整检验进程中可能引进的不确定度来源进行确认,搭建数学方法模型,推演测算各来源不确定度的占比,获得石油蜡中所含正构烷烃浓度测定的扩展不确定度。分析结果显示,该标准方法不确定度的主要来源为重复性测定和样品称量,而内标溶液配制与稀释对不确定度影响较小。以正构烷烃C_(32)、C_(42)和C_(52)为例,取置信概率为95%,包含因子k=2,石油蜡中所含正构烷烃质量分数的测定结果为WC_(32)=1.01%±0.04%、WC_(42)=0.18%±0.02%、WC_(52)=0.06%±0.01%。Gas Chromatography Method for Determination of N-alkanes and Non-N-alkanes Content and Carbon Number Distribution in petroleum waxes(NB/SH/T 0653—2021) was selected as the petrochemical industry standard specification,n-C_(16) was used as the internal standard,and hydrogen flame ionization sensor gas chromatograph was used to detect the mass fraction of n-alkanes contained in petroleum waxes.The uncertainty sources in the process of complete inspection were confirmed,and the mathematical method model was built to deduce and calculate the proportion of uncertainty of each source,so as to obtain the extended uncertainty of the determination of n-alkane concentration in petroleum wax.The analysis results showed that the main sources of uncertainty of the standard method were repeatability determination and sample weighing,and the preparation and dilution of internal standard solution had little effect on the uncertainty.Taking the n-alkanes C_(32),C_(42) and C_(52) for example,and the measurement results of the mass fraction of n-alkane contained in petroleum wax was WC_(32)=1.01%±0.04%,WC_(42)=0.18%±0.02%,WC_(52)=0.06%±0.01%,when the fiducial probability was 95% and the coverage factor(k) was 2.

关 键 词：不确定度 石油蜡 正构烷烃 气相色谱法 

分 类 号：O657[理学—分析化学]