The successful combination of gas chromatography with mass spectrometry (MS) stimulated the efforts to combine liquid chromatography (LC) with MS. In the mass spectrometer, the belt passes through a heated chamber adjacent to the ion source, where the sample is flash vaporized into the ion source block. Several analytical techniques and modifications of the belt interface have been suggested to cope with the many compromises necessary for LC-MS. Some special derivatives show improved mass spectral behavior due to an increase in volatility and generation of abundant molecular ions and structurally significant fragmentations. For every substance an ion current was produced in the mass spectrometer that served as a universal detector for the high-performance liquid chromatography (HPLC) analysis of lipids. In some cases, mass spectra of the reduction products reflected the structure of the parent compound. Direct coupling of HPLC effluents to a mass spectrometer is possible by utilizing several different techniques.

Commercial software Carburane, developed at the IFP Energies Nouvelles, was originally designed to accurately evaluate petroleum fraction quality. It can also be applied to forensic problems, and in particular to arson investigation. During a 15-month period, about 350 premium gasoline samples, representative of the three types available on the French territory (SP95, SP95-E10, SP98), were obtained from different oil companies and their associated distribution networks. Samples were collected in gas stations, placed in sealed containers, securely packaged, and were next analysed in the IRCGN laboratory by high resolution capillary column GC (gas chromatography) with flame ionisation detection for the separation and characterisation of different hydrocarbon families. Data processing using Carburane software provided accurate characterisation and comparison of premium gasoline samples that could have been used as fire accelerants. It could assess the closeness of unburned premium gasoline samples found at a crime scene, with similar samples from gas stations or from searched suspect premises. Application to the real case study of a burned residential house provided useful information to the investigators.

An analytical method was developed to characterize puparia cuticular lipids (hydrocarbons, waxes) and to compare the molecular distribution patterns in the extracts from either recent or older puparia. Acid-catalyzed transesterification and solvent extraction and purification, followed by combined gas chromatography coupled to mass spectrometry, were optimized for the determination of hydrocarbons and fatty acid ethyl esters from transesterified waxes, extracted from a single species of a fly scavenger (Hydrotaea aenescens Wiedemann, 1830). Comparison between recent (2012) or older (1997) puparia contents has highlighted significant composition differences, in particular, a general decrease of the chain length in the n-alkane distribution pattern and, on the contrary, an increase of the ester chain length. Both extracts contain traces of three hopane hydrocarbon congeners. Preliminary results evidence the change in puparia lipid composition over time, thus potentially providing new indices for estimating postmortem interval.

On décrit dans cet article les principales techniques d'analyse des dérivés du pyrrole dans les pétroles et les produits pétroliers et on présente les principaux résultats obtenus. La méthode la plus efficace consiste en une concentration de ces composés par chromatographie liquide; l'identification des principaux composés individuels se fait par chromatographie gazeuse et son couplage avec la spectrométrie de masse. On a essentiellement identifié ou caractérisé : le carbazole et certains de ses dérivés alkylés, les dibenzo(a)-, -(b)- et -(c)carbazoles et certains de leurs dérivés alkylés, certains dibenzocarbazoles. D'un point de vue géochimique, il semble évident que ces composés ne sont pas des molécules fossiles, Il est également apparu des différences de comportement de ces composés les uns par rapport aux autres vis-à-vis de l'hydrotraitement catalytique. This article describes the leading techniques for analyzing derivatives from pyrrole in oil and petroleum products. The main results obtained are described. The most effective method consists of a concentration of these compounds by liquid chromatography. The main individual components are identified by gas chromatography and its coupling with mass spectrometry. The principal compounds identified or characterized were carbazole and some of its alkylated derivatives, dibenzo(a)-, -(b)- and -(c)carbazoles and some of their alkylated derivates, and various dibenzocarbazoles. From the geochernical standpoint, it seems obvious that these compounds are not fossil molecules. Differences in behavior were also found for these compounds in relation to others with regard to catalytic hydrotreatment.

A multi-residue analytical method for six pesticides (atrazine, hydroxyatrazine, carbofuran, promecarb, linuron and monolinuron) in drinking water has been developed. The method combines liquid chromatography and mass spectrometry using an ionspray interface. The linearity domain, as well as the limits of detection and quantification, were determined for each compound. Although satisfactory performance could be achieved, present drinking water regulations (0.1 μg l−1 for single pesticide) requires a pre-concentration step. This was performed using solid-phase extraction with octadecyl-bonded silica cartridges. The analytical procedure was tested on water samples spiked at the 0.04 and 0.08 μg l−1 levels, and allowed the determination of the investigated pesticides (except hydroxyatrazine) at these trace concentrations.

Linear oligogalacturonic acids (1,4-linked alpha-D-galacturonic acid oligomers), obtained by partial acid hydrolysis of orange polygalacturonides, were studied by negative-ion electrospray ionization mass spectrometry, without prior sample derivatization. After preparative separation using high-resolution anion-exchange chromatography, some fractions enriched in uronic acids were desalted, transferred into a methanol + water solution adjusted to pH 10, and directly submitted to electrospray ionization mass spectrometry in the negative-ion recording mode. Clear molecular mass assignments of the oligomers, covering a degree of polymerization between 4 and 7, were obtained.

Proteins from skim milk, paracaseinate and whey have been successfully analyzed by reverse-phase high-performance liquid chromatography (RP-HPLC) coupled with electrospray ionization mass spectrometry (ESI-MS). The major milk proteins were identified by comparison of molecular masses determined by ESI-MS to molecular masses calculated from amino acid composition deduced from primary structures and cDNA sequences for some proteins. This method has permitted the simultaneous identification of caseins and whey protein variants. Observed molecular masses of major milk proteins were found to be 19 038.0 +/- 2.2 Da for kappa-CN A-1P (number of experiments n = 6); 19 007.0 +/- 1.1 Da for kappa-CN B-1P (n = 4); 25 230.0 +/- 2.1 Da for alpha(s2)-CN A (n = 9); 23 617.2 +/- 1.3 Da for alpha(s1)-CN B-8P (n = 14); 24 092.0 +/- 1.7 Da for beta-CN B-5P (n = 6); 24 025.3 +/- 1.0 Da for beta-CN A(1)-5P (n = 14); 23 984.8 +/- 0.7 Da for beta-CN A(2)-5P (n = 14); 18 278.3 +/- 2.2 Da for the monomeric form of beta-LG B (n = 5); 18 364.8 +/- 1.6 Da for the monomeric form of beta-LG A (n = 5); 14 179.21 +/- 3.14 Da for alpha-LA (n = 5). Hence an accuracy of 0.01% was obtained by ESI-MS analysis. It was also shown that the on-line coupling of HPLC with ESI-MS offers a very promising alternative for studying the proteolysis and determining the specificity of used enzymes in some technological treatments as shown for milk-clotting enzymes.

Rapid Communications in Mass SpectrometryVolume 1, Issue 2 p. 29-33 Article Application of a combined supercritical fluid chromatograph–mass spectrometer to the investigation of gas phase ion–molecule reactions Patrick J. Arpino, Corresponding Author Patrick J. Arpino Ecole Polytechnique, Department of Chemistry, 91128 Palaiseau, FranceEcole Polytechnique, Department of Chemistry, 91128 Palaiseau, FranceSearch for more papers by this authorJ. Cousin, J. Cousin Ecole Polytechnique, Department of Chemistry, 91128 Palaiseau, FranceSearch for more papers by this authorE. Gelpi, E. Gelpi Sponsor Referee Centro de Investigacion y Desarrollo, SpainSearch for more papers by this author Patrick J. Arpino, Corresponding Author Patrick J. Arpino Ecole Polytechnique, Department of Chemistry, 91128 Palaiseau, FranceEcole Polytechnique, Department of Chemistry, 91128 Palaiseau, FranceSearch for more papers by this authorJ. Cousin, J. Cousin Ecole Polytechnique, Department of Chemistry, 91128 Palaiseau, FranceSearch for more papers by this authorE. Gelpi, E. Gelpi Sponsor Referee Centro de Investigacion y Desarrollo, SpainSearch for more papers by this author First published: June 1987 https://doi.org/10.1002/rcm.1290010208Citations: 3AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume1, Issue2June 1987Pages 29-33 RelatedInformation

On décrit dans cet article les principales techniques d'analyse des dérivés du pyrrole dans les pétroles et les produits pétroliers et on présente les principaux résultats obtenus. La méthode la plus efficace consiste en une concentration de ces composés par chromatographie liquide; l'identification des principaux composés individuels se fait par chromatographie gazeuse et son couplage avec la spectrométrie de masse. On a essentiellement identifié ou caractérisé : le carbazole et certains de ses dérivés alkylés, les dibenzo(a)-, -(b)- et -(c)carbazoles et certains de leurs dérivés alkylés, certains dibenzocarbazoles. D'un point de vue géochimique, il semble évident que ces composés ne sont pas des molécules fossiles, Il est également apparu des différences de comportement de ces composés les uns par rapport aux autres vis-à-vis de l'hydrotraitement catalytique.

Les composes azotes non basiques, extraits selectivement de deux huiles brutes de meme origine, mais differentes par leur etat de biodegradation, sont le carbazole, les benzocarbazoles, les dibenzocarbazoles et leurs derives alkyles

Separation and identification by gas chromatography and gas chromatography—massspectrometry of the nitrogen compounds from a deasphalted heavy oil. Evolution oftheir distribution after a catalytic hydrotreatment

Fractions highly enriched in pyrrole benzologues have been extracted from a coker gas oil before and after hydrotreatment under selected operating conditions. Carbazole, methyl- and dimethylcarbazoles and benzocarbazoles have been identified by means of g.c. coelutions with standards. The study of these compounds after catalytic hydrotreatment has shown that benzocarbazoles are more effectively removed than carbazoles in highly hydrogenating conditions (partial pressure of hydrogen, 10 MPa; temperature, 360 °C) whereas alkyl carbazoles and more particularly 1-methyl derivatives are more altered at a high temperature (380 °C, partial pressure of hydrogen, 5 MPa).

Les indices de retention du carbazole, des methylcarbazoles, des dimethylcarbazoles et de leurs derives N-methyles ont ete mesures sur trois phases de polarites et de caracteristiques differentes (OV 73, OV 61, OV 1701)

Petroleum tetra-aromatic aza-arenes have been analysed by a combination of chromatographic and spectroscopic techniques. Nearly identical and simple distributions of individual compounds were found in the oils which were investigated. Two major series of compounds, isosteric with chrysene and benzo[a]anthracene, were detected. A methylated azachrysene derivative, 6-methylbenzo[c]-phenanthridine, has been identified by means of GC, GC-MS and high resolution spectrofluorescence at T = 15 K. The structural analogy between this compound and its lower benzologs of the benzo[h]quinoline and quinoline series (i.e. occurrence of a methyl group on the carbon alpha to the nitrogen atom and location of this heteroatom) is noticeable.

The investigation of nitrogen bases occurring in a coker gas oil before and after catalytic hydrotreatment has shown important differences in reactivity of azaarenes. Compounds with a low degree of aromaticity are relatively resistant compared with higher benzologues. Particularly stable are α-methylated azaarenes, which are also major nitrogen bases found in crude oils. Alkyl anilines, the last intermediates before denitrogenation, are the most abundant bases in hydrotreated samples.