Assessing Biodegradation in the Llanos Orientales Crude Oils by Electrospray Ionization Ultrahigh Resolution and Accuracy Fourier Transform Mass Spectrometry and Chemometric Analysis
详细信息 查看全文
- 作者：Boniek G. Vaz ; Renzo C. Silva ; Cl茅cio F. Klitzke ; Rosineide C. Simas ; Heliara D. Lopes Nascimento ; Rosana C. L. Pereira ; Diego F. Garcia ; Marcos N. Eberlin ; D茅bora A. Azevedo
- 刊名：Energy & Fuels
- 出版年：2013
- 出版时间：March 21, 2013
- 年：2013
- 卷：27
- 期：3
- 页码：1277-1284
- 全文大小：461K
- 年卷期：v.27,no.3(March 21, 2013)
- ISSN：1520-5029
文摘
Focusing on the O2 class, a set of crude oils from Llanos Orientales Basin, Colombia, were classified in terms of biodegradation levels using negative ion mode electrospray Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and chemometric analysis. The O2 class, which is mainly composed of naphthenic carboxylic acids, was monitored because these polar crude oil constituents are known to be substantially affected by microbial activity. Principal component analysis (PCA) applied on the O2 profile was able to classify the crude oils into three groups: biodegraded, mixture, and non-biodegraded. From the relative abundances of the O2 class, a clear trend on acid distribution could be directly correlated with biodegradation: a rising in abundance of saturated acids with low double-bond equivalent (DBE) values (despite the lowering observed for fatty acids with DBE = 1), expressed by the A/C index. The combined use of two indexes, the A/C index and a new index also based on saturated acid abundances, the SA index, is proposed as an effective strategy to monitor biodegradation. This approach showed to be particularly useful to fill blanks on discrete biodegradation classification and when samples are actually composed of a mixture of oils with contrasting biodegradation levels. Results are in good agreement with predictions based on classical hydrocarbon biomarker analysis.