Compound type analysis

Suatoni, J.C. Swab, R.E. Preparative Hydrocarbon Compound Type Analysis by High Performance Liquid Chromatography, J. Chromatogr. Sci. 1976,14, 535. 

Roussis, S.G. Cameron, A.S. Simplified Hydrocarbon Compound Type Analysis Using a Dynamic Batch Inlet System Coupled to a Mass Spectrometer. Energy... 

Compound type analysis was not conducted in this work, but it is instructive to look at some literature results. With respect to heteroatoms, tar sand bitumen and petroleum asphaltenes have been variously reported as containing predominantly polar heteroatoms, principally oxygen types (18) or nonpolar heteroatoms, principally nitrogen types (14). The difference in these reported results apparently relates to the method of analysis in which the former is a direct determination, the latter an indirect determination. 

This column blank is not to be confused with sample blanks such as those determined for the 5-gal. jugs. This latter blank correction is applied to (1) extractable organics and nonvolatile hydrocarbon contents measured by the method and (2) UV and GC data. No correction from the sample blank is applied to the compound type analysis by mass spectrometer. Very little net error can be attributed to this omission of a blank correction. 

Snyder, L.R. Nitrogen and Oxygen Compound Types in Petroleum. Total Analysis of a 400-700oF Distillate from a California Crude Oil, Anal. Chem. 1969, 41, 314. 

Daams et al. (1992) have analysed all the cubic structure types reported in Villars and Calvert (1985), after excluding all oxides and a few types with improbable interatomic distances, thus leaving 128 structure types representing 5521 compounds. Their analysis showed that these cubic structure types have 13 917 atomic environments (point sets). Of those environments, 92% belong to one of the 21 most frequently occurring AET, which are those reported in the following list (see also Fig. 3.18) ... 

Mass spectrometry enables the type of direct analyses described, but it does have its limitations. Online operation forces detection at infusion concentrations, in salty buffer and under complex mixture conditions. General ion suppression results from the buffer and mixture components, and mixture complexity can tax the resolution of even the best mass spectrometers. Increasing compound concentration is not the answer, as this leads to problems of solubility and increased compound consumption. We have found that the online method can work successfully for up to 100 compounds per analysis, but the false negative rate becomes appreciable [21]. As an alternative for ligand discovery purposes, we have developed a FAC-LC/MS system in which FAC effluent is sampled and analyzed by LC/MS [19]. This system offers the ability to concentrate mixture components and introduces another dimension to the data in order to tolerate more complex mixtures (Fig. 6.9). Using this system, we have screened approximately 1000 modified trisaccharide acceptor analogs targeting immobilized N-... 

Every analysis performed on columns of this type (for example, carbohydrates, alcohols, organic acids, mixtures of these) can be improved with a column in the most suitable ionic form, even though solutions with compounds of differing types may impose the choice of a compromise. In analytical practice, however, it is not advisable to make an in-column conversion from one form to another, for the resin could shrink or even swell in relation to the type of cation linked. The effect of fixed-cation is made obvious when the compounds under analysis can coordinate with it, as in the case of carbohydrates. For example, the linkage of sugars with three adjacent hydroxyls may be more stable than those that have only two, with obvious effects in the resolution of the analytes. Finally, it is advisable to use a guard column to prolong the life of the... 

The results of the infrared analysis are presented in Table VI. These results show that carboxylic acids and phenols are found only in the acid concentrates. Carboxylic acids are concentrated in the polar acid subfractions III and IV while phenols are concentrated in subfraction II. Carbazoles, ketones, and amides are found in all three major nonhydrocarbon fractions. The appearance of the same compound type in several fractions may arise from differences in acidity or basicity that are caused by the hydrocarbon portion of the molecule. Multifunctionality could also be a factor in the distribution of compound types among the fractions. The 1695 cm"1 band was assigned to ketones on the basis of work... 

The comparison of a number of dialytic extracts with the parent coals is given in Table 1L These results indicate that the elemental composition of the dialytic extract closely mirrors that of the organic fraction of the coal. Similar conclusions were reached when coal liquids were separated via the dialytic method. The conclusion that dialysis does not concentrate any particular compound type deserves further investigation, since obtaining a representative sample is crucial to the utility of the method. In Table H, it is particularly interesting to note that in each case the "organic sulfur 1 from the classical coal analysis is almost identical to the sulfur content directly determined on the dialytic extract. 

The newly developed 600 MHz NMR Spectrometer is used to characterize coal-derived liquids and their chromatographically separated fractions. The distinct and well resolved proton resonance lines in both aromatic and aliphatic regions and IR analysis have been used to identify the major compounds and compound types. Double resonance technique has been applied for the chemical shift identification of donor protons (or-CHg, p-CH,) of partially hydrogenated polynuclear aromatic compounds. An NMR difference technique is applied to determine specific compositional changes in upgraded liquids derived under identical process conditions, but from different coal sources. 

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