PETR 158 |
| We report here our study of field desorption (FD) ionization and electrospray ionization (ESI) of hydrocarbon polymers, vacuum distillation bottoms (boiling point higher than 1000„aF) and asphaltenes. Field Desorption is the primary method in petroleum analysis to desorb and ionize heavy petroleums. The technique has an effective desorption/ionization range of 300 to 5000 Da for hydrocarbon molecules. In spite of its extensive use, FDMS has not been validated quantitatively for heavy petroleum characterization. We took a systematic approach to address this issue. Polystyrenes of a wide average molecular weight range (MW of 580-2970 g/mol) were used to determine the MW response factor. In addition, a heavy petroleum sample was fractionated by both boiling point and by solvent fractionation. These samples were used to determine the effect of boiling point and chemical classes. Electrospray Ionization is selective toward the ionization of polar molecules. A comparison of ESI and FD measurement reveals variation in molecular weight distribution of polar and non-polar molecules. The ionization efficiency of ESI as a function of MW and boiling point is also studied. |
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Characterization, On-Line Monitoring, and Sensing of Petroleums and Petrochemicals
8:30 AM-11:30 AM, Thursday, 14 September 2006 Palace -- Marina Room, Oral
Division of Petroleum Chemistry |