bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of mono‐ to tetracyclic aromatic hydrocarbons in lubricating oil
Authors: Paschke Angelika , Herbel Walter , Steinhart Hans , Franke Stephan , Francke Wittko 
Published: May 2005

AbstractLiquid – liquid extraction with N‐methyl‐2‐pyrrolidone, combined with solid‐phase extraction on silica gel using n‐pentane and dichloromethane as solvents, has been used for the isolation and concentration of the aromatic fraction from lubricating oil.The identification of individual compounds in this aromatic fraction was performed by capillary gas chromatography–mass spectrometry (CGC‐MS) and by determination of retention indices. Quantitative results were obtained by flame ionization detection (CGC‐FID). Eighty four compounds, predominantly naphthalenes, phenanthrenes, biphenyls, fluorenes, dibenzo‐thiophenes, and their alkylated derivatives, have been identified in a commercial lubricating oil. The total amount of the aromatic fraction did not exceed 0.04 % of the oil.
Optimization of conditions in static headspace GC
Authors: Penton Zelda 
Published: May 2005

AbstractThe precision and sensitivity of head‐space GC can be improved by careful selection of the operating conditions: partitioning in the vapor phase can be promoted by altering the sample matrix; the ratio of the volumes of the gaseous and liquid phases, the sample temperature, the equilibration time, and the effect of sample mixing should also be considered.Most of the principles covered here can be applied to either manual headspace GC or to headspace GC utilizing an automated sampler.
Determination of polynuclear aromatic hydrocarbons in water samples using large volume on‐column injection capillary gas chromatography
Authors: Morabito Paul L. , McCabe Terry , Hiller Joseph F. , Zakett Don 
Published: May 2005

AbstractAn automated large volume on‐column injection technique for capillary gas chromatography (GC) with solvent divert and heated retention gap technology has been utilized to determine polynuclear aromatic hydrocarbons (PAHs) in samples of industrial plant process water. Injecting large sample volumes on‐column enabled the sample preparation procedure to be simplified and provided a fast, labor‐saving technique for screening water samples. Diverting approximately 95% of the solvent away from the analytical column and the detector enabled chromatography to reflect classical capillary loading and detector conditions.Simplifications include significant reduction of sample and eluent volumes used during extraction and the elimination of Kuderna‐Danish evaporative concentration. System performance, such as linearity and limit of detection, were evaluated for selected PAHs. Spiked water samples were prepared in the lower μ/L range to determine extraction efficiency. Results are compared with those obtained by a reputable contract laboratory following EPA Method 625.
High performance liquid chromatographic separation of polar and non‐polar chlorophyll pigments from algae using a wide pore polymeric octadecylsilica column
Authors: Garrido José L. , Zapata Manuel 
Published: May 2005

AbstractA method employing a wide pore polymeric reversed phase column has been developed for the separation of most of the chlorophylls and related compounds previously described as occurring in marine microalgae. The high selectivity toward molecular shape of this kind of stationary phase has enabled compounds of very similar structure, such as chlorophylls c1, c2 and Mg‐divinylpheoporphyrin a5 monomethyl ester, and chlorophyll a and the phytol‐substituted chlorophyll c‐like pigments, which commonly coelute on monomeric bonded phases, to be resolved in a single run. Some of these pigments, formerly thought to be a single compound, have, in fact, been demonstrated to be groups of two or more. The method has been successfully applied to both algal cultures and natural sea water samples. When visible light absorbance detection was used, the method proved suitable for separation of various carotenoids.
What hinders the further development of capillary GC?
Authors: Grob Konrad , Schilling Beat 
Published: May 2005

AbstractCapillary GC was invented a long time ago – in this respect it is aging – but its potential is still far from being fully exploited and it is still an excellent playground for analysts looking for rewarding subjects. The author laments that there is not more activity in the field, provides some tips and subjects for anyone wishing to make his profession more colorful, and does not agree with managers who believe that “lean analysis”, i.e. execution of recipes without any experimenting with the technique, is cost‐effective. Good analysts somewhat resemble artists in character, but can be highly profitable for a laboratory, provided they are given the background to be creative.
Selective and sensitive detection of organic contaminants in water samples by on‐line trace enrichment–gas chromatography–mass spectrometry
Authors: Bulterman Albert‐J. , Vreuls Jolan J. , Ghijsen Rudy T. , Brinkman Udo A. Th. 
Published: May 2005

AbstractLiquid chromatographic (LC) type trace enrichment is coupled online with capillary gas chromatography (GC) with mass spectrometric (MS) detection for the analysis of aqueous samples. A volume of 1–10 ml of an aqueous sample is preconcentrated on a trace‐enrichment column packed with a polymeric stationary phase. After cleanup with HPLC‐grade water the precolumn is dried with nitrogen and subsequently desorbed with ethyl acetate. A fraction of 60 μl is introduced on‐line into a diphenyltetramethyldisilazane‐deactivated retention gap under partially concurrent solvent evaporation conditions and using an early solvent vapor exit. The analytes are separated and detected by means of GC–MS. The potential of the LC–GC–MS system for monitoring organic pollutants in river and drinking water is studied. Target analysis is carried out with atrazine and simazine as model compounds; the detection limits achieved under full‐scan and multiple ion detection conditions are 30 pg and 5 pg, respectively. Identification of unknown compounds (non‐target analysis), is demonstrated using a river water sample spiked with 168 pollutants varying in polarity and volatility.
Use of open‐tubular trapping columns for on‐line extraction–capillary gas chromatography of aqueous samples
Authors: Mol Hans G. J. , Janssen Hans‐Gerd , Cramers Carel A. 
Published: May 2005

AbstractThe applicability of open‐tubular trapping columns for on‐line extraction–capillary GC analysis is evaluated. The extraction step involves sorption of the analytes from water into the stationary phase of an open‐tubular column, removal of the water by purging the trap with nitrogen, and desorption of the analytes with an organic solvent. The effect of swelling of the stationary phase with organic solvents on the retention power of the trap is studied. When using pentane or hexane as swelling agent breakthrough volumes of at least 10 ml can easily be obtained for non‐polar compounds. For a number of medium polarity compounds breakthrough volumes of 5 ml can be achieved when chloroform is used as the swelling agent. The required drying time is less than 1 minute. Quantitative desorption requires only 75 μl of organic solvent. Solvent elimination prior to transfer to the GC column is carried out using a PTV injector and a multidimensional GC system. The system is applied for the analyses of river water, urine, and serum samples.
Quantitative aspects of directly coupled supercritical fluid extraction–capillary gas chromatography with a conventional split/splitless injector as interface
Authors: Lou Xianwen , Janssen Hans‐Gerd , Cramers Carel A. 
Published: May 2005

AbstractThe quantitative aspects of on‐line supercritical fluid extractioncapillary gas chromatography (SFE‐GC) with a split/splitless injector as interface were investigated. Special attention was paid to the discrimination behavior and the reproducibility of the split/splitless interface. A simple experimental set‐up is proposed that allows accurate quantitation in on‐line SFE‐split GC. The results obtained in on‐line SFE‐GC compare favorably with those from conventional GC with split injection. Discrimination was found to be absent when working at sufficiently high interface temperatures. Finally, the effects of the carbon dioxide flow rate, interface temperature and split ratio on both discrimination and reproducibility were studied.
Capillary gas chromatography—atomic emission detection: A useful instrumental method in pesticide residue analysis of plant foodstuffs
Authors: Stan Hans‐Jürgen , Linkerhägner Manfred 
Published: May 2005

AbstractThe high selectivity of element‐specific atomic emission detection has proven suitable for screening analysis of plant foodstuffs for pesticide residues by capillary gas chromatography, especially for those foodstuffs which contain high levels of matrix compounds. The elemental composition of a peak can, furthermore, be examined by looking at the partial emission spectra recorded during a GC run. This instrumental feature prevents false positive signal interpretation as a result of high concentration levels of eluting matrix compounds.
Simultaneous hydrothermal decomposition and methylation: High resolution gas chromatography–mass spectrometry for polymer characterization
Authors: Oguri Naoki , Onishi Akira , Uchino Sigeki , Nakahashi Keiji , Yamasaki Nakamichi , Jin Xigao 
Published: May 2005

AbstractHigh speed hydrothermal decomposition of some chemically inert condensation polymers in alkaline solutions under near‐critical pressures and temperatures has been investigated by on‐line Curie‐point heating–high resolution GC‐MS. The technique also involves simultaneous methylation with tetramethylammonium hydroxide in a 1 mm i.d. × 20 mm sealed glass capillary. The relative standard deviation for the peak intensity (mol %) resulting from ten replicate measurements of poly(butylene terephthalate) is approximately 3%. This method requires a small amount of sample (ca. 0.1 mg) and provides simple chromatograms, greater structural information, good reproducibility, and rapid reaction (0.5–15 min) without chemical treatment. A brief overview of applications to the characterization of some condensation polymers such as aromatic polyester, polycarbonate, and aliphatic and aromatic polyamide is also described.
An overview of LC–MS interfacing systems with selected applications
Authors: Garcia J. F. , Barceló D. 
Published: May 2005

AbstractAdvantages and limitations are described for the different LC–MS interfacing systems (moving belt; direct liquid introduction; thermospray; atmospheric pressure ionization with heated pneumatic nebulizer, electrospray, or high flow ion spray; particle beam; and continuous flow fast atom bombardment). Some comments are also made about interfacing capillary zone electrophoresis (CZE).The peculiarities of the various interfaces are described, as are liquid chromatographic requirements prior to mass spectrometry using the different ionization techniques. Selected biological and environmental applications are given.
Element‐selective detection using capillary gas chromatography with atomic emission detection
Authors: Cooke M. , Leathard D. A. , Webster C. , Rogerson V. 
Published: May 2005

AbstractCapillary GC coupled to an atomic emission detector (AED) provides a powerful new hyphenated technique for the separation and characterization of complex mixtures and compounds. The AED provides simultaneous and truly specific multi‐element detection. The specificity of detection reduces the need for the complex sample pretreatment procedures which are necessary to reduce the interference from co‐eluted substances which is experienced with detectors such as the FID and the ECD. A range of environmentally significant problems has been studied, including PCB analysis, the characterization of the reaction products of a novel waste treatment process, and the profiling of sulfur‐containing species formed by the pyrolysis of various types of coal.
Rapid determination of phytanic acid in human blood serum by selectivity tuning in packed column SFC
Authors: Lembke Peter , Engelhardt Heinz 
Published: May 2005

AbstractA new packed column SFC method has been developed for the determination of phytanic acid in human blood serum. Because of the low viscosity and high diffusion coefficient of supercritical carbon dioxide, several columns can be connected in series, significantly improving separation. Series connection of columns which differ in their selectivity enables the adjustment of the total selectivity towards the individual separation problem (‘selectivity tuning’). In this instance it was possible, after transesterification into their ethyl esters, to separate all the fatty acids in human blood serum, including phytanic acid, by coupling three columns (silica, amino‐propyl, and RP8) in series.
Enantioselective separations by capillary GC on derivatized cyclodextrins. Part 1: Separation of some racemic 2,2‐dialkyl‐4‐alkoxycarbonyl‐1,3‐dioxolane derivatives on permethylated α‐, β‐ and γ‐cyclodextrins
Authors: Jaques K. , Buda W. M. , Pottie M. , Van der Eycken J. , Vandewalle M. , Venema Arnold , Sandra Pat 
Published: May 2005

AbstractThe enantioseparation of some 2,2‐dialkyl‐4‐alkoxycarbonyl‐1,3‐dioxolane derivatives, which are important intermediates in the total synthesis of a number of biologically active compounds, was studied by means of capillary gas chromatography (CGC). The chromatographic results, obtained on columns coated with permethylated α‐, β‐ and γ‐cyclodextrin respectively, are reported. Out of sixteen compounds, thirteen could be separated with a resolution superior to 1,2. One racemate could not be separated on any of the columns. Considerations concerning the separation mechanism are proposed.
On‐line microwave‐induced helium plasma atomic emission detection for capillary zone electrophoresis
Authors: Liu Yan , Lopez‐Avila Viorica 
Published: May 2005

AbstractWe report a feasibility study on using a microwave‐induced helium plasma atomic emission detector (MIP‐AED) as an on‐line detector in capillary zone electrophoresis (CZE). To couple CZE to MIP‐AED, we used an ion exchange membrane capillary to connect the separation capillary to the interfacing capillary. The outlet end of the interfacing capillary was placed directly in the discharge tube of the MIP‐AED system. The electroosmotic flow generated in the separation capillary carried the analytes and the electrolyte buffer solution through the interfacing capillary into the MIP‐AED discharge tube where the analytes were detected. The performance of the CZE/MIP‐AED system was evaluated with trimethyltin chloride, dimethyltin dichloride, n‐propanol, and 2‐butanone. The preliminary results indicate that the MIP‐AED can be used in CZE to provide element‐specific detection for target analytes.
Capillary gas chromatography combined with high performance liquid chromatography for the structural analysis of olive oil triacylglycerols
Authors: Toschi Tullia Gallina , Christie William W. , Conte Lanfranco S. 
Published: May 2005

AbstractThe triacylglycerol composition of olive oil samples has been determined by stereospecific analysis after partial hydrolysis with ethyl magnesium bromide, derivatization, preparative chiral HPLC, transesterification, and GC quantitation of fatty acid methyl esters. The data obtained for position sn‐2 were compared with those from capillary GC analysis of monoacyl sn‐2‐glycerols after enzymatic lipolysis of triacylglycerols.The determination of triacylglycerols collected by silver ion HPLC and quantified (as fatty acid methyl esters) by GC, together with direct GC analysis on a polar column, have then furnished a comprehensive picture of the triacylglycerol content of olive oil.
Analysis of sorbitan ester surfactants. Part I: High performance liquid chromatography
Authors: Wang Zhendi , Fingas Merv 
Published: May 2005

AbstractSorbitan ester surfactants are very complicated mixtures. An improved and simple reversed phase high performance liquid chroma tographic (HPLC) method employing a C18 column has been developed for the rapid separation of sorbitan ester surfactants and the quantitative determination of the distribution of sorbitan mono‐, di‐, tri‐, and tetraester fractions. The sorbitan ester distribution of the six Span and Arlacel surfactants studied was calculated using relative response factors obtained from analysis of pure glycerides of fatty acids. The effects of mobile phase composition on the accuracy and reliability of the distribution values calculated for the sorbitan esters were investigated.
High resolution gas chromatographic determination of the atmospheric reactivity of engine‐out hydrocarbon emissions from a spark‐ignited engine
Authors: Kaiser Edward W. , Siegl Walter O. 
Published: May 2005

AbstractThe reactivities of engine‐out exhaust hydrocarbon (HC) emissions in photochemical smog formation have been determined for three fuels (isooctane, an aromatic blend, and a gasoline) in a single‐cylinder, spark‐ignited engine. High resolution capillary GC was used to determine the mole fractions of the exhaust hydrocarbon species. Temperature programmed chromatography on a single capillary column was sufficient to separate the major exhaust species. A library of approximately 160 hydrocarbon species was used to identify typically 90–95 % of the HC species present. GC‐MS was used selectively to verify peak assignments.The effect of engine operating parameters (fuel‐to‐air ratio, spark timing, and speed) on reactivity was examined. Engine operating parameters affect both total emissions [g/mile] and the specific atmospheric reactivity [g ozone/g HC emissions] of these emissions. Changing the operating parameters to control total emissions may not be as effective as expected in controlling the total reactivity [g ozone/mile] of the emissions because the specific reactivity can also change simultaneously. Effects of changes in operating parameters differ significantly as the type of fuel is varied. The ability to measure exhaust hydrocarbon species emissions accurately and quickly will increase in importance as reactivity‐based emissions standards come into widespread use.
Simultaneous determination of volatile aromatic and halogenated hydrocarbons in water and soil by dual‐channel ECD/PID equilibrium headspace analysis
Authors: Kolb Bruno , Bichler Christine , Auer Maria , Voice Thomas C. 
Published: May 2005

AbstractVolatile aromatic and halogenated hydrocarbons are determined in water and soil samples by equilibrium headspace gas chromatography. Simultaneous analysis is carried out in a dual column/dual detector arrangement with ECD and PID. Their determination in contaminated soil is performed with the same instrumental configuration. However, in contrast to water analysis, an increased sample temperature was found necessary for highly adsorptive soil specimens. At sample temperatures of 95 °C, recoveries near 100% have been found. Both adsorption and desorption processes were found to be strongly time‐dependent.
Identification of fatty acid methyl esters as minor components of fish oil by multidimensional GC‐MSD: New furan fatty acids
Authors: Wahl Hans Günther , Liebich Hartmut M. , Hoffmann Andreas 
Published: May 2005

AbstractThe separation and analysis of furan fatty acids and other minor component fatty acids present at very low concentrations in complex sample matrices, such as fish oil or lipids derived from liver and testes, require several pre‐analytical separation steps if single column gas chromatography is to furnish sufficient resolution: after extraction and transesterification hydrogenation, urea complex precipitation and argentation TLC have been applied prior to GC analysis of furan fatty acids.By using multidimensional GC‐MSD with cooled injection and flow‐controlled column switching with intermediate cold trapping, it has been possible to identify directly the methyl esters of furan fatty acids without further pre‐analytical separation.The most common of the furan fatty acids can be subdivided into two groups depending on whether they bear a propyl or pentyl side group in the 5‐position of the furan ring. In addition to the eight furan fatty acids known to be present in fish oil, six new ones were identified, four with propyl substitution and two with pentyl substitution. Four have earlier been reported to be present in the hepatopancreas of crayfish and in fish tissue, whereas the propyl‐substituted 16,19‐epoxy‐17,18‐dimethyldocosa‐16,18‐dienoic acid and the pentyl‐substituted furan fatty acid 6,9‐epoxy‐7‐methyltetradeca‐6,8‐dienoic acid were hitherto unknown.
Determination of sulfur components in natural gas: A review
Authors: Tuan Hai Pham , Janssen Hans‐Gerd , Cramers Carel A. , Smit André L. C. , van Loo Ellen M. 
Published: May 2005

AbstractMore stringent environmental regulations as well as higher demands presently being imposed on the sulfur content of natural gas feed‐stocks for chemical processes necessitate the development of new analytical procedures for sulfur determination in natural gas. Only analytical procedures based on gas chromatography can meet the sensitivity and accuracy requirements dictated by environmental regulation institutions and modern chemical industry. The complexity of the natural gas matrix as well as the extremely low concentration levels at which the sulfur species occur make the development of these analytical methods a true challenge. In this review the three steps common for analytical methods for trace analysis in complex matrices, i.e. pretreatment, chromatographic separation, and detection, are discussed in detail. Possible methods for calibration of the system are discussed in the final section.Various techniques to determine sulfur in natural gas are described. Depending on the application, the most suitable system has to be selected. For example, for on‐line application in a hazardous area a simple and rugged system is required, i.e. a simple gas chromatograph with a flame photometric detector, while for laboratory application a more complex instrument including preconcentration, column switching, and more exotic detection systems could be more suitable. Therefore it is crucial to define the requirements of the instrument at an early stage and use the information in this review article to develop/select a dedicated instrument/procedure for the problem at hand.
Characterization of fuel samples by on‐line LC‐GC with automatic group‐type separation of hydrocarbons
Authors: Trisciani A. , Munari F. 
Published: May 2005

AbstractCharacterization of fuels by LC‐GC is possible by use of automatic successive transfer (multiple transfer) of HPLC fractions to a GC via an on‐column interface. This paper describes the instrumentation and the methodology for the HPLC separation of the hydrocarbons (aliphatic and aromatic) into separate groups and the on‐line transfer of these groups to a capillary GC column. Two HPLC methods were used with the same valve configuration: single column (silica) with column back‐flush to detector; and double column (silica and amino‐bonded silica) with multiple fraction transfer and back‐flush. The first method was used for the analysis of total saturated compounds and total aromatic compounds; the second was used for the separation of the one‐, two‐, three‐, and four‐ring aromatic compounds present in diesel fuels. Examples are shown of the characterization of diesel fuels, and the repeatability of the data.