bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multichannel autosampler for Curie‐point pyrolysis capillary gas chromatography
Authors: Oguri Naoki , Onishi Akira , Hanai Toshihiko , Jin Xigao 
Published: May 2005

AbstractA multichannel autosampler which can automatically analyze up to 20 samples in sequence has been developed for on‐line Curie‐point pyrolysis – capillary GC. The results obtained from the system show that the analysis of thermally labile samples could be performed without either thermal degradation or reaction during the waiting time before the final pyrolysis. The reproducibilities of the relative peak areas and retention times of the characteristic pyrolysates of a tricomponent copolymer were significantly better than those obtained by manual sample manipulation.
Analysis of carbohydrates by HPLC with post‐column derivatization
Authors: Krämer Michael , Engelhardt Heinz 
Published: May 2005

AbstractPost‐column derivatization of oligosaccharides after HPLC separation with a variety of systems has been achieved either by reaction with thymol in concentrated sulfuric acid or after hydrolysis of saccharides with hydrochloric acid and derivatization of the resulting monosaccharides with p‐aminobenzoic acid hydrazide. With both reactions the detection of reducing and non‐reducing sugars is possible even at trace levels. The latter reaction, despite the two reaction steps required, is much more convenient and practical, whereas with the first reaction it is also possible to determine alkylpolyglucosides.
Determination of estrogens in animal tissue by GC‐MS with negative ion chemical ionization
Authors: Busico Fabio , Moretti Gabriella , Cartoni Giampaolo P. , Rosati Felice 
Published: May 2005

AbstractGC‐MS with negative ion chemical ionization has been used to detect anabolic estrogens (diethylstilbestrol, dienestrol, hexestrol, and 17β‐ and 17α‐estradiol) in bovine muscle tissue. After hydrolysis and extraction, purification by column chromatography, and derivatization, the detection limit for the estrogens is better than 0.1 ppb.
Enantiomeric resolution of dansyl phenylalanine and analogs by microcolumn liquid chromatography with γ‐cyclodextrin as mobile phase additive
Authors: Takeuchi Toyohide , Nagae Norikazu 
Published: May 2005

AbstractDansyl derivatives of racemic phenylalanine and its analogs have been resolved by microcolumn liquid chromatography with γ‐cyclodextrin as mobile phase additive. The enantioselectivity of the system was influenced by the concentrations of both γ‐cyclodextrin and acetonitrile in the mobile phase. Enantiomers of phenylalanine, phenylglycine, and tyrosine were resolved by isocratic elution in a single chromatographic run.
Capillary gas chromatographic determination of free amino acids in honey as a means of discrimination between different botanical sources
Authors: Pirini Annalisa , Conte Lanfranco S. , Francioso Ornella , Lercker Giovanni 
Published: May 2005

AbstractThe chemical analysis of honey tends to concentrate on factors related to its state of preservation, e.g. HMF, diastase activity, and water content. Although there is no characteristic of honey officially regarded as suitable for certification of its botanical origin, literature is available in which several of the “minor” components of honey, such as flavors, di‐ and trisaccharides, and free amino acids, have been used to certify the botanical origin of the product.In this paper, six kinds of honey from different botanical sources (acacia, citrus fruit, chestnut‐tree, rhododendron, rosemary, and lime‐tree) were analyzed by capillary gas chromatography, and the data obtained evaluated statistically to determine whether the amino acid profile could be used to verify the botanical source of the material.The results have shown that the presence of amino acids such as arginine, tryptophan, and cystine is characteristic of a particular kind of honey, and that others, such as proline, asparagine, lysine, and methionine, can be used for discrimination if quantitative data is available about the levels of the compounds present.Evaluation of optimum split ratio for amino acid determination, and problems concerning the derivatization process, are also discussed.
The investigation and application of the packed glass capillary column with a core
Authors: Yang Haiying , Lu Wanzhen 
Published: May 2005

AbstractA new type of packed glass capillary column (PGCC) with a core, and its potential usage in practice are described. The permeability of the column is considerably greater than that of conventional PGCC and its N/(Pi‐Po) value is also higher. This novel PGCC column has been successfully applied to the analysis of trace levels of ethyne, cyclopropane, propadiene, propyne, and other C1C4 impurities in pure ethene, propene, 1,3‐butadiene, and catalytic cracking gas samples as well as other petrochemical gases such as liquified petroleum gas.
Improvements in flame photometric detector design and operation. Determination of organophosphorus pesticide residues at low picogram levels
Authors: Verga G. R. 
Published: May 2005

AbstractThe molecular emission of heteroelements such as phosphorus and sulfur is the basis of the selective response of the flame photometric detector. The behavior of the FPD towards phosphorus compounds has been studied and design improvements sought with regard to burner configuration and temperature distribution. The possibility of differentiating between compounds containing phosphorus atoms and those containing both phosphorus and sulfur atoms has also been examined.Detection limits and response characteristics have been reported for organophosphorus pesticide residues in samples of natural origin
A continuous two‐phase reaction system coupled on‐line with capillary chromatography for the determination of polar solutes in water
Authors: Goosens Elise C. , Broekman Marcel H. , Wolters Margarete H. , Strijker Richard E. , de Jong Dirk , de Jong Gerhardus J. , Brinkman Udo A. Th. 
Published: May 2005

AbstractGas chromatographic procedures are described for the determination of carboxylic acids and chlorinated anilines in water samples.Propionic acid and 2,6‐difluorobenzoic acid in aqueous solution have been simultaneously alkylated and extracted by means of a continuous two‐phase reaction system, and then quantitated by on‐line coupled capillary gas chromatography; tetrahexyl‐ammonium hydrogen sulfate was used as phase transfer catalyst and pentafluorobenzyl bromide as reagent.A factorial design approach was used to optimize on‐line derivatization of aqueous propionic acid with regard to pH and concentration of phase transfer catalyst. Alkylation and extraction, under optimized conditions, followed by quantitation of the pentafluorobenzyl ester by flame ionization detection furnished a linear calibration for concentrations between 0.1 and 10 μg/ml. The relative standard deviation was 9–15 %.The continuous two‐phase reaction system was also used to determine (chlorinated) anilines present in water at concentrations of 0.1–1 μg/ml; pentafluorobenzoyl chloride was used as reagent and analysis was performed by capillary gas chromatography with flame ionization or electron capture detection. The on‐line acylation of p‐chloroaniline was optimized with regard to pH, reagent concentration, and reaction time.The on‐line reaction system worked satisfactorily for both applications, although excess reagent caused some problems with the chromatography.
High temperature gas chromatography on narrow bore capillary columns
Authors: Damasceno Lucia M. P. , Cardoso Jari N. , Coelho Ricardo B. 
Published: May 2005

AbstractThe use of high‐temperature‐stable, medium polarity glass capillary columns coated with immobilized PS‐090 (a 20 % diphenyl‐substituted, CH3O‐terminated polydimethylsiloxane) has made it possible to analyze routinely, and with good separation efficiency, high molecular weight compounds such as triglycerides and free base porphyrins. Cold on‐column injection was used throughout this work to avoid discrimination against involatile compounds, and disposable (fused silica) retention gaps were used to protect the column against contamination with involatile material. On‐column injection into narrow bore glass columns was achieved by using glass‐to‐silica connections to attach wider bore (0.2 mm i.d.) deactivated fused silica tubing to the columns.
Coupled fused silica capillaries for rapid capillary zone electrophoresis of proteins
Authors: Nashabeh Wassim , Rassi Ziad El 
Published: May 2005

AbstractA novel two‐dimensional electrophoretic system for the control of electroosmosis in capillary zone electrophoresis has been developed and evaluated for rapid separations of proteins. The system comprises uncoated and polyether‐coated fused silica capillaries coupled in series. An equation relating the average electroosmotic flow velocity in the coupled capillaries to the intrinsic electroosmotic velocities of the connected segments and their corresponding lengths has been derived and verified experimentally. This approach has the advantage of enabling the electroosmotic flow to be tuned independently of the applied voltage. As a consequence, rapid protein analysis at relatively low field strength was achieved without sacrificing the high separation efficiencies obtained with surface‐modified capillaries.
Analysis of deethyl‐ and deisopropylatrazine residues in drinking and ground water by chemical derivatization
Authors: Pachinger Anton , Eisner Elisabeth , Tertsch Claudia , Begutter Helmut , Klus Hubert 
Published: May 2005

AbstractA gas chromatographic method with alkali flame ionization detection is described for the determination of residue levels (0.1 μg/I and below) of deethylatrazine and deisopropylatrazine in drinking and ground water. Confirmation of the identities of the compounds is achieved by trifluoroacetylation, reaction conditions for which are presented.
Quantitation of diethylene glycol monoethyl ether in citrus oils
Authors: Bonetti Graziano , Pibarot Patrick , Chaintreau Alain , Marion Jean Paul 
Published: May 2005

AbstractThe use of diethylene glycol monoethyl ether as a flavor solvent is restricted. Since existing methods of quantitation are tedious or require sophisticated multi‐dimensional GC instrumentation, a simple method has been developed using low cost GC‐MS. Monitoring of ions 31 and 45 enables quantitation of DEGEE in essential oils at levels down to 1 μg/g with accuracy equal to or better than 15%.
Sample evaporation in conventional split/splitless GC injectors: Part 2: Use of perylene for visual observation of three different scenarios in empty injector inserts
Authors: Grob Konrad , De Martin Mirella 
Published: May 2005

AbstractPerylene is strongly fluorescent as long as it is in solution. This has enabled visual observation of non‐evaporated sample material in a “transparent injector”, i.e. in a heated glass device imitating a conventional vaporizing injector.Three scenarios of sample evaporation are described. Some samples (solvents) are nebulized and “flash evaporated” in the gas phase between the needle exit and the column entrance (Scenario 1). With most solvents, the liquid leaves the syringe needle as a thin jet which rushes through both the empty vaporizing chamber and the split outlet at high velocity, often without substantial evaporation. It does not touch the surfaces of the insert and passes round the bend at the bottom of the device without any problem (Scenario 2). Some samples are splashed on to the insert wall, wet it, and evaporate rather slowly from this surface (Scenario 3).
Headspace gas analysis: Comparison of the efficiency of thick film, ultra thick film, and activated charcoal open tubular capillary traps for the concentration of volatile, airborne, organic compounds
Authors: Burger Barend V. , le Roux Maritha 
Published: May 2005

AbstractDetermination of the rate at which volatile organic molecules diffuse through the wall of a polysiloxane rubber tube, shows that the full depth of the rubber lining of ultra‐thick film open tubular traps is utilized for the retention of volatile organic compounds in headspace gas analysis. Small apolar molecules migrate rapidly through the rubber, but larger molecules and polar compounds diffuse relatively slowly into the rubber. Neither traps with a thick film of an apolar stationary phase, nor those with an ultra thick polysiloxane rubber lining retain highly volatile compounds very effectively. Traps containing activated charcoal particles fused into their inside glass surface have a much higher capacity than those with activated charcoal particles embedded in a layer of stationary phase.
Multidirmensional gas chromatography – isotope ratio mass spectrometry (MDGC‐IRMS). Part A: System description and technical requirements
Authors: Nitz Siegfried , Weinreich Bernd , Drawert Friedrich 
Published: May 2005

AbstractA system is presented which combines multidimensional GC with isotope ratio mass spectrometry. The performance of the system is demonstrated with an application from the field of flavor analysis. Potentials and limitations of the technique are also discussed.
New artificial standards for the HPLC analysis of natural glucosinolates
Authors: Elfakir Claire , Lafosse Michel , Viaud Marie Claude , Dreux Michel 
Published: May 2005

AbstractThe separation of new, artificial, non‐sulfated glucosinolates and desulfated natural glucosinolates on different apolar (C8, TMS, phenyl) or weakly polar (CN) bonded stationary phases by gradient elution has shown that apolar or weakly polar bonded silica‐based adsorbents, in addition to the C8 phase chosen for the standard procedure, can be used with benefit for the analysis of glucosinolate mixtures.The use of new artificial glucosinolates, not present in cruciferae, as internal standards for the standard HPLC method for the determination of the main glucosinolate composition and content of rapeseed is discussed.The main factors influencing the retention and selectivity toward several natural and artificial non‐sulfated glucosinolates for different chromatographic systems have been studied, and for additional information the retention data have been analyzed statistically by factor analysis.The first results from this study show that the mechanism of the HPLC retention of glucosinolates is the sum of only two methematically independent physico‐chemical phenomena. The first is associated with the hydrophobicity of compounds.A better understanding of the chromatographic behavior of glucosinolates has made it possible to investigate the synthesis of new, artificial standard glucosinolates with the intention of providing an ideal standard for every kind of analysis. It also supplies a tool to enable laboratories to choose the best chromatographic system for a particular selectivity problem.
Separation of mixtures of solvents with wide bore capillary columns connected in series
Authors: Gerbino Tomaso C. , Castello Gianrico 
Published: May 2005

AbstractThe gas chromatographic separation of the components of a complex mixture of industrial solvents, not possible on a single stationary phase owing to coelution of some of the compounds, has been achieved on two serially connected wide bore capillary columns of different polarity.The analysis of a mixture of twenty five compounds was optimized using the serial gas chromatography theory of Purnell and Williams. The capacity factors of sample components measured with the two columns coupled in series were found to agree with those predicted by theory, regardless of the order in which they were connected.
On‐line liquid chromatography – gas chromatography for automated clean‐up and analysis of polycyclic aromatic hydrocarbons
Authors: Östman Conny , Bemgård Agneta , Colmsjö Anders 
Published: May 2005

AbstractA fully automated system, comprising a liquid chromatograph (LC) coupled on‐line to a gas chromatograph (GC) by means of a loop interface, has been constructed for clean‐up and analysis of polycyclic aromatic hydrocarbons (PAH). An autosampler was utilized for sample injection into the LC. By the use of a back‐flush technique in conjunction with an ordinary analytical aminopropylsilica column, PAH could be isolated by LC: a concurrent solvent evaporation injection technique was then used for on‐line transfer of the PAH fraction to the GC, where the PAH analysis was completed.Compared with ordinary off‐line LC clean‐up followed by GC analysis, the sensitivity has been increased by a factor of 50–100, yielding a detection limit for individual PAH of a few nanograms per sample when using flame ionization detection. Further, irreproducible losses of low molecular weight PAH as a result of solvent evaporation steps in off‐line clean‐up procedures have been eliminated. Reproducibility of retention times and relative peak areas is high, facilitating automatic peak identification and calculation of concentrations, and the system can thus be used for automatic sample evaluation. The total time required for clean‐up and analysis is only 1.5 hours, and the demand on personnel time for the analysis of PAH has been drastically reduced.The technique has been demonstrated with samples of urban air and of used automobile engine lubricating oil.
CZE separations of basic proteins at low pH in fused silica capillaries with surfaces modified by silane derivatization and/or adsorption of polar polymers
Authors: Gilges Martin , Husmann Heribert , Kleemiß Maria‐Helen , Motsch Stephan R. , Schomburg Gerhard 
Published: May 2005

AbstractMixtures of several basic proteins have been used to test CZE capillaries with surfaces modified by new pretreatment procedures; the performance obtained has been compared with that achieved using capillaries treated by procedures described in the literature.It has been shown that addition of non‐ionic polyvinylalcohols (PVA) to CZE buffer solutions deactivates even bare, i.e. untreated, fused silica surfaces and renders them suitable for separations of basic proteins. The performance obtained from such surfaces was comparable with that of capillaries modified by the more elaborate procedures of etching, silanol derivatization, and/or adsorptive coating (again with polymers).A home‐made device is described which enables derivatization and coating reactions to be performed on fused silica capillaries under an inert atmosphere, i.e. one free from oxygen and water.
Unified gas and supercritical fluid chromatography on 50 μm i.d. Columns
Authors: Tong Daixin , Bartle Keith D. , Clifford Anthony A. , Robinson Robert E. 
Published: May 2005

AbstractA unified approach to sequential gas and supercritical fluid Chromatography using 50 μm i.d. open tubular columns is described. Sample introduction is performed by means of a rotary injection valve. In order that linear velocities can be optimized independently, a second rotary valve in the chromatographic oven is used to direct the flow of column eluate to the flame ionization detector through either fused silica tubing in GC, or a frit restrictor in SFC.Applications of sequential GC‐SFC on a 50 μm i.d. open tubular column are demonstrated, and comparisons made between sequential GC‐SFC on 50 and 100 μm i.d. columns.
Reproducibility of sample separation using liquid or forced air convection thermostatted high performance capillary electrophoresis systems
Authors: Landers James P. , Oda Robert P. , Madden Benjamin , Sismelich Tamara P. , Spelsberg Thomas C. 
Published: May 2005

AbstractRun‐to‐run sample separation reproducibility has been compared on two commercial high performance capillary electrophoresis units which differ in the mode by which the capillary temperature is thermostatted. Three standard analytes, differing dramatically in molecular character and size, were used for the analysis: benzoic acid, a 14 amino acid peptide from human chorionic gonadotropin, and ribonuclease A represent, respectively, small stable organic molecules, small peptides with little or no secondary structure, and proteins with secondary structure. These standards were evaluated with regard to reproducibility of migration time, peak area, and peak height. The analyses, performed in buffers of optimum pH for the separations, demonstrated that the liquid and forced air convection thermostatted systems both performed extremely well. The reproducibility, as judged by the percent coefficient of variance (% CV) of replicate analyses, was generally found to be less than 1 % (migration time); the reproducibility decreased in the order migration time > peak height > peak area. Whereas the absolute % CV values for MTrel (migration relative to a standard) observed with the liquid thermostatted system were 2‐ to 4‐fold lower than those observed with the forced air convection thermostatted system, there was little statistically significant difference between the two. As expected, the data indicated a reduction in reproducibility as the complexity of the analyte increased, perhaps as the result of an increased potential for wall interactions. Comparing separations in which low (≈︁1 watt/meter [W/m] of capillary) and high (>5 W/m) Joule heat was generated by altering the sodium chloride content of the buffer revealed few statistically significant differences in the reproducibility obtained from the two systems. With these particular standard analytes and their respective buffer systems, there appears to be little difference between forced air convection and liquid thermostatting of the capillary.
Application of coupled LC‐GC to the analysis of the polar fraction of diesel particulate matter
Authors: Kelly Grant W. , Bartle Keith D. , Clifford Anthony A. , Robinson Robert E. 
Published: May 2005

AbstractEmissions from diesel engines contain mutagenic compounds, many of which are derivatives of polycyclic aromatic hydrocarbons. The complexity of extracts of particulate matter requires multi‐stage chromatographic analysis performed off‐line.In this study, coupled LC‐GC is presented as an alternative method for the analysis of the polar fraction of extracts of diesel particulate matter. Preseparation of the sample was achieved by normal phase HPLC and fractions were transferred to the GC through an on‐column interface. Through selective transfer, extensive characterization of the extract is possible and chromatograms can be greatly simplified, thus aiding identification.
Optimum performance of capillary GC columns as a function of column diameter and film thickness under various operating conditions: Part II: Computer program extensions for n‐alkane solutes and polydimethylsiloxane phases
Authors: Leclercq Piet A. 
Published: May 2005

AbstractA BASIC computer program for calculation of maximum plate number and minimum analysis time conditions for columns operated at various outlet pressures was presented in 1985 [1]. This sequel reports extensions to the program for n‐alkanes separated on polydimethylsiloxane stationary phases, specifically for n‐C2 through n‐C20 on phases equivalent to SE‐30 or OV‐1. For these solute–phase systems the amount of thermodynamic data available is sufficient to enable calculation of several parameters.Firstly, the separation temperature is now automatically calculated for a requested capacity ratio, or vice versa. Secondly, the computation of solute diffusivities in the stationary phase has been improved to approach experimental data more realistically, particularly for higher n‐alkanes at higher temperatures.The largest extension to the program is the inclusion of a facility enabling calculation of column sample capacity, minimum detectable amounts for FID and TCD detectors, and column working ranges. These parameters are again calculated for n‐alkanes, but are, of course, independent of the nature of the stationary phase. The updated program has been and is being used on a routine basis in our laboratory; it has been found to be reliable and has on numerous instances been proven in the field.