Probe microdistillation/mass spectrometry in the analysis of high-boiling petroleum distillates

Abstract

Results for a monoaromatics fraction from the 535-675 °C distillate of a Wilmington, CA, crude oil demonstrate the efficacy of probe mlcrodlstlllation/mass spectrometry for the qualitative and quantitative analysis of mixtures containing relatively nonvolatile substances. The probe temperature was controlled by a programmer either linearly or to maintain a constant ion current by feedback of the voltage from the Ion current monitor to the programmer. Ions were produced by 70-eV and 10-eV electrons and by field Ionization. Qualitatively, all three methods of Ionization produced the same spectral patterns. Detectable compounds are distributed in

Electrospray ionization mass spectrometry of metalloporphyrins

“…Metalloporphyrins have been analyzed using a variety of mass spectrometric methods, including electron ionization (EI),1,2 chemical ionization (CI),3h8 fast atom bombardment,9h12 plasma desorption,13,14 thermospray,15 laser desorption,16h19 Ðeld desorption, 20 atmospheric pressure chemical ionization21 and electrospray ionization (ESI).22h24 Traditionally, EI and CI are useful for structural elucidation studies but complicate the analysis of mixtures as they produce mass spectra containing a large number of fragment ions. The remaining ionization methods generally produce a high abundance of molecular ions with little fragmentation, and are therefore useful for identiÐcation purposes.…”

Generating electrospray from solutions predeposited on a copper wire

“…[1][2][3][4][5][6] The direct probe is advantageous in that analysis is complete in a relatively short time and, except for EI and CI, the intact molecular ions can be detected from thermally labile compounds thus introduced. The technique is conventionally applied to rapidly characterize components in purified samples, such as individual eluent fractions collected from liquid chromatography (LC), or synthetic products which are normally quite pure, thereby making further chromatographic separation unnecessary.…”

Solubility of hydrogen in well-defined coal liquids

“…The new solubility data, XH, agree with our previous data and those of Chao along the 189. 6 °C Isotherm, as well as for the 50-atm points at 268.7 and 389.1 °C. However, the new solubility data are about 10% higher than previously measured at 250 atm at both 268.7 and 389.1 °C.…”

“…10:1 ratio of the m/z 106 and 91 ions from ethylbenzene and at a resolution of ca. 1500 with a Kratos MS-30 mass spectrometer (6). Samples were introduced into the Ion source (300 °C) via a reservoir inlet (325 °C), and the LV/EI/MS were recorded in triplicate.…”

“…In addition, it is Important to note that these phenomena 0 Calculated on basis of mass-spectral analysis on the aromatic fraction of the distillate only. 6 Normalized to the total distillate; aromatic fraction as received = 92% of total, aromatic fraction after 400 °C run = 91.7% of total. 'SWRI data (2).…”