On-line desalting of crude oil in the source region of a Fourier transform ion cyclotron resonance mass spectrometer.
The presence of dissolved metal ions in waters associated with crude oils has many negative implications for the transport, processing, and refining of petroleum. In addition, mass spectrometric analysis of sodium containing crude oil samples suffers from ionization suppression, unwanted adduct formation, and an increase in the complexity of data analysis. Here, we describe a method for the reduction/elimination of these adverse effects by modification of the source region gas-inlet system of a 12 T Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. Several acids were examined as part of this study, with the most suitable for on-line desalting found to have both high vapor pressure and low pK(a); 12.1 M HCl showed the strongest desalting effect for crude oil samples with a sodium removal index (SRI) of 88%-100% ± 7% for the NaOS compound class. In comparison, a SRI of only 38% ± 9% was observed for a H₂O/toluene solution-phase extraction of oil 1. These results clearly demonstrate the increased efficacy of pseudo-vapor phase desalting with the additional advantages that initial sample solution conditions are preserved and no sample preparation is required prior to analysis.
Petroleum Reservoir Group, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada, kiew2000@hotmail.com.
C Ken
CK
Chanthamontri
Andrew P
AP
Stopford
Ryan W
RW
Snowdon
Thomas B P
TB
Oldenburg
Stephen R
SR
Larter
D019342:Acetic Acid / Q000737:chemistry; D053000:Analytic Sample Preparation Methods; D057205:Automation, Laboratory; D017357:Cyclotrons; D005561:Formates / Q000737:chemistry; D005583:Fourier Analysis; D006851:Hydrochloric Acid / Q000737:chemistry*; D007202:Indicators and Reagents / Q000737:chemistry*; D010578:Petroleum / Q000032:analysis*; D012965:Sodium Chloride / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D055548:Vapor Pressure
D005561:Formates; D007202:Indicators and Reagents; D010578:Petroleum; C030544:formic acid; D012965:Sodium Chloride; D019342:Acetic Acid; D006851:Hydrochloric Acid