Characterization of nitrogen-containing compounds in petroleum fractions by online reversed-phase liquid chromatography-electrospray ionization Orbitrap mass spectrometry. (15th January 2021)

• Record Type: Journal Article
• Authors: Xia, Yueyi; Ma, Chenfei; Ju, Ran; Zhao, Chunxia; Zheng, Fujian; Sun, Xiaoshan; Li, Zaifang; Wang, Chunyan; Shi, Dejun; Lin, Xiaohui; Lu, Xin; Xu, Guowang
• Is Part Of: Fuel. Volume 284(2021)
• Publication Date: 2021-01-15
• Subjects: Nitrogen-containing compounds -- Petroleum fraction -- Online Reverse phase liquid chromatography -- High-resolution mass spectrometry; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2020.119035
• Languages: English
• ISSNs: 0016-2361

Abstract

Graphical abstract: Highlights: An online RPLC-Orbitrap MS method was proposed to characterize nitrogen-containing compounds in heavy petroleum faction. Both basic and neutral nitrogen compounds were well characterized simultaneously in positive ESI mode. False-positive element composition assignment was excluded by retention behaviors of homologues series and isomers. Similar characterization results were obtained between RPLC-Orbitrap MS and 15 T FT-ICR MS. Abstract: Characterization of heteroatom compounds in crude oils is very important in petroleum production and processing. The ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) is a powerful MS technique for it but with expensive costs. It is necessary to develop a generally accepted alternative analytical approach to replace FT-ICR MS. In this study, a reversed-phase liquid chromatography (RPLC)-high-resolution (HR) MS method was proposed on an Orbitrap MS with electrospray ionization (ESI). The optimal chromatographic and MS parameters and internal mass calibration method were suggested. The sample complexity was greatly reduced by RPLC separation. Mass resolution (240 K at m / z 200) of Orbitrap MS was enough to obtain an accurate elemental assignment in complex petroleum fractions. False-positive element composition assignment could be easily excluded by the RPLC retention behavior of isomers. The performance of RPLC-Orbitrap MS was evaluated in comparison with direct injection (DI)-FT-ICR MS and DI-Orbitrap MS in positive ion mode for heavy oil analysis. The results showed that heteroatom class species, DBE vs carbon number distributions were very similar between RPLC-Orbitrap MS and DI-FT-ICR MS. The developed methods were further used to analyze petroleum oil fractions with boiling ranges at 180–350 °C, 350–530 °C and >530 °C. Detailed heteroatom class species and corresponding DBE vs carbon number distributions were obtained. This study demonstrated that the RPLC-Orbitrap MS technique could successfully be applied for heteroatom compound characterization in petroleum fractions.