Aerosol Dynamics, Inc. , Berkeley, California 94710, United States.
Chemical Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
Environ Sci Technol. 2015 Nov 17;49(22):13130-8. doi: 10.1021/acs.est.5b03472. Epub 2015 Oct 28.
Comprehensive chemical information is needed to understand the environmental fate and impact of hydrocarbons released during oil spills. However, chemical information remains incomplete because of the limitations of current analytical techniques and the inherent chemical complexity of crude oils. In this work, gas chromatography (GC)-amenable C9-C33 hydrocarbons were comprehensively characterized from the National Institute of Standards and Technology Standard Reference Material (NIST SRM) 2779 Gulf of Mexico crude oil by GC coupled to vacuum ultraviolet photoionization mass spectrometry (GC/VUV-MS), with a mass balance of 68 ± 22%. This technique overcomes one important limitation faced by traditional GC and even comprehensive 2D gas chromatography (GC×GC): the necessity for individual compounds to be chromatographically resolved from one another in order to be characterized. VUV photoionization minimizes fragmentation of the molecular ions, facilitating the characterization of the observed hydrocarbons as a function of molecular weight (carbon number, NC), structure (number of double bond equivalents, NDBE), and mass fraction (mg kg(-1)), which represent important metrics for understanding their fate and environmental impacts. Linear alkanes (8 ± 1%), branched alkanes (11 ± 2%), and cycloalkanes (37 ± 12%) dominated the mass with the largest contribution from cycloalkanes containing one or two rings and one or more alkyl side chains (27 ± 9%). Linearity and good agreement with previous work for a subset of >100 components and for the sum of compound classes provided confidence in our measurements and represents the first independent assessment of our analytical approach and calibration methodology. Another crude oil collected from the Marlin platform (35 km northeast of the Macondo well) was shown to be chemically identical within experimental errors to NIST SRM 2779, demonstrating that Marlin crude is an appropriate surrogate oil for researchers conducting laboratory research into impacts of the DeepWater Horizon disaster.
要了解石油泄漏过程中释放的碳氢化合物在环境中的归宿和影响，需要全面的化学信息。然而，由于当前分析技术的限制和原油固有的化学复杂性，化学信息仍然不完整。在这项工作中，通过气相色谱（GC）与真空紫外光电离质谱（GC/VUV-MS）联用，从美国国家标准与技术研究院标准参考物质（NIST SRM）2779 墨西哥湾原油中全面表征了可进行 GC 分析的 C9-C33 碳氢化合物，其质量平衡为 68±22%。该技术克服了传统 GC 甚至全面二维气相色谱（GC×GC）面临的一个重要限制：为了进行表征，必须使彼此之间相互分离的化合物进行色谱分离。VUV 光电离最小化了分子离子的碎裂，便于根据分子量（碳原子数，NC）、结构（双烯当量数，NDBE）和质量分数（mg kg-1）对所观察到的碳氢化合物进行特征化，这些参数是了解其归宿和环境影响的重要指标。直链烷烃（8±1%）、支链烷烃（11±2%）和环烷烃（37±12%）占主导地位，其中最大贡献来自于含有一个或两个环和一个或多个烷基侧链的环烷烃（27±9%）。对于 100 多种成分的子集和化合物类别总和的线性度和与之前工作的良好一致性为我们的测量提供了信心，这代表了对我们分析方法和校准方法的首次独立评估。从 Macondo 井东北 35 公里处的 Marlin 平台收集的另一种原油在实验误差范围内与 NIST SRM 2779 化学性质相同，这表明 Marlin 原油是研究人员进行深海地平线灾难影响的实验室研究的合适替代油。
