bluuebunny/crossref_metadata_2025_split huggingface dataset:
Head space gas chromatography with glass capillaries using an automatic electropneumatic dosing system
Authors: Kolb B. , Pospisil P. , Borath T. , Auer M. 
Published: May 2005

AbstractHead space GC using a special electropneumatic sampling system works well in combination with glass capillaries. Because a homogenous gas mixture is already present most problems inherent with inlet splitters are thus avoided. In cases where the high vapor pressure of the sample can cause problems with the pressure controlled sampling system, the use of narrow bore glass capillaries provides the necessary inlet pressure. The use of this powerful and convenient analytical tool for water pollution analysis, flavour analysis and the analysis of volatiles in crude oil samples is shown by examples.
The preparation of glass SCOT columns by the organic glue method
Authors: Zu‐Fong Lue , Yuen‐Yu Tung , Rhan‐Mei Chao , Qing‐Yu Ou , Pei‐Yi Yang , Kun‐Nian Dong , Wei‐Lu Yu 
Published: May 2005

AbstractA technique for adhesion of fine particles (ca. 5 μ) of the 405 white diatomaceous support on the inner wall of glass tube with organic glue [poly (diethylaminoethyl methacrylate) acetate] is described. The coated tube was drawn to capillary column by using a machine designed according to Desty's. The capillary column was then coated with stationary phase (such as squaiane, QF‐1, Dexsil 300, PEG 20 M, OV‐1, SE 30 and etc.) by the conventional dynamic or static method. This preparation method has proved easy to duplicate and is simple. The coating efficiency (UTE %) is within 60–90. The theoretical plate number per meter of an SE 30 column is about 4000, and per meter of a PEG 20 M column is about 2500. The columns thus prepared have been successfully used to analyze petroleum hydrocarbons, essential oils, petrochemicals, pheromone, steroid metabolites and others.
Sample capacity in open tubular and micro‐packed columns for GC
Authors: Pretorius V. , Smuts T. W. 
Published: May 2005

AbstractEquations have been derived from which the maximum sample size which may be loaded on a column without significantly affecting the performance may be calculated. It is shown that micro‐packed columns can handle a sample which is as much as forty times larger than that which can be loaded onto wall‐coated open tubular columns with comparable conditions.
Thin‐layer adsorption chromatography with mixed mobile phases. 2. Effects of solute‐solvent interactions and energetic heterogeneity of surfaces with regard to admolecules in TLC
Authors: Rózyło J. K. , Jaroniec M. , Jaroniec J. A. , Kolodziejczyk H. 
Published: May 2005

AbstractIn the Part 1 of this series a new equation for determining the Rm values in TLC with mixed mobile phases was proposed and examined by using the parameter m, which is a measure of energetic heterogeneity of the adsorbent surface with regard to the adsorbing molecules (admolecules).The numerical values of m, evaluated for 13 chromatographic systems, have been compared with that of the Ościk's parameter A, which characterizes solute‐solvent interactions.
High resolution gas chromatography/mass spectrometric characterization of urinary metabolites of N,N‐diethyl‐m‐toluamide (DEET) in man
Authors: Wu Anthony , Lynn Pearson M. , Shekoski David L. , Soto Ricardo J. , Stewart Richard D. 
Published: May 2005

AbstractStudies of the pharmacology and toxicology of the popular insect repellant, N,N‐diethyl‐m‐toluamide (DEET), have largely been done in animal models using radioactive tracing without the structural elucidation of its metabolites.This paper describes a high resolution gas chromatography/mass spectrometry (GC/MS) technique and reports the results of the preliminary characterization of the metabolites of DEET in the urine of a 30‐year‐old man who had been exposed to DEET contained in a commercial product. The metabolites were extracted and separated with an OV‐101 glass capillary column, 30 m × 0.3 mm, and mass spectrometric elucidations were carried out with both Electron Impact (EI) and Chemical Ionization‐Methane (MCI) modes.Oxidation of the benzylic moiety and hydroxylation of the sidechain of DEET molecules appeared to be the predominate routes of metabolism in man. The artifacts were also proposed.
Isomers of uroporphyrin free acids separated by HPLC
Authors: Wayne A. W. , Straight R. C. , Wales E. E. , Englert E. 
Published: May 2005

AbstractA synthetic mixture of uroporphyrin isomers I, II, III and IV as free acids in the synthetic ratio of 1:1:4:2 was resolved by reverse‐phase HPLC using a C0:PEL (ODS) 37‐50 micron precolumn and a Micro Bondapak C18 analytical column eluted with acetonitrile (4%) in phosphate buffer (pH 6.95). Clinically important I and III isomers of uroporphyrin were readily resolved directly from acidified urine as porphyrin free acids.
Preparative high‐performance liquid chromatography with reversed phase packed glass columns
Authors: Eisenbeiß F. , Henke H. 
Published: May 2005

AbstractAn efficient system for preparative reversed‐phase separations with packed glass columns is described. The advantage of this system is the use of relatively simple and inexpensive equipment.Column performance, load capacity, effect of the feed volume and the feed concentration on peak broadening are shown. The influence of the selectivity and the capacity factors on column load have been measured.The effect of the column dimensions is demonstrated by means of practical applications. The loading capacity of a column depends on the thermodynamic proporties of the separation system used. It is therefore not expedient in preparative chromatography to correlate the loading capacity of a column by means of grams dissolved per grams of adsorbent.
Adsorption of [14C] phenytoin in a gas chromatographic system
Authors: Driessen O. , Emonds A. 
Published: May 2005

AbstractThe labelled drug [14C] phenytoin was injected into an all‐glass chromatographic system to determine adsorption on various system parts. It appeared that 10 to 20% of the amount injected did not elute. Severity of adsorption as measured from lasting radioactivity was not anticipated from peak shape or calibration curves.
Advancing the chromatography of GC/FT‐IR to WCOT capillary columns
Authors: Shafer K. H. , Bjørseth A. , Tabor J. , Jakobsen R. J. 
Published: May 2005

AbstractBy the use of a wide‐bore WCOT capillary column, it was possible to obtain the first on‐the‐fly GC/FT‐IR spectra with a WCOT column. This wide‐bore WCOT column gave improved separation, as compared to a SCOT column, and yielded identifiable infrared spectra for a real sample.
Odour evaluation, fraction collection and preparative scale separations with glass capillary columns
Authors: Sandra P. , Saeed Talat , Redant G. , Godefroot M. , Verstappe M. , Verzele M. 
Published: May 2005

AbstractA simple but effective GC approach to odour evaluation and fraction collection with capillary columns is described. An allglass device splits the column effluent, with one splitter arm going to an FID. For odour evaluation, the other splitter arm is led via teflon tubing to the nose. Off‐line heart‐cutting is carried out by collecting the split effluent on a glass capillary microtrap, the inner walls of which are coated with OV‐101. This allows recovery of nanogram amounts of material. Multipass operation or repeated collection leads to preparative capillary GC for further spectroscopic investigation. These techniques do not involve sophisticated equipment or valves. Applications of this type of smell analysis, heart‐cutting and enrichment in the analysis of Rhododendron fragrantissimum essential oil, black pepper essential oil and hop essential oil, illustrating the versatility of the systems, are presented.
Quantitative densitometric determination of reserpine and ajmaline in Rauwolfia Vomitoria by HPTLC
Authors: Katič M. , Kušan E. , Prošek M. , Bano M. 
Published: May 2005

AbstractA direct densitometric method for the quantitative measurement of reserpine and ajmaline in whole roots and bark of roots of Rauwolfia Vomitoria, after extraction and separation by thin‐layer chromatography, is described. The emission and excitation spectra of the reserpine and the absorption spectrum of the ajmaline were scanned. The linear range between peak area and concentration is given.
Determination of alcohols in gasoline blends using a multi‐dimensional switching system
Authors: Ševčik J. 
Published: May 2005

AbstractMethanol, 2‐Me‐propanol‐2, propanol‐2, benzene, toluene and xylenes in gasoline blends were determined using a valveless multi‐dimensional switching system (MDSS) with two packed columns and temperature programming.Compounds of interest, interfering with paraffins and naphthenes, were in a sequence of four heart cuts transferred onto the second column. The resulting baseline separation enabled precise quantitative measurement within a short analysis time. Instrument settings, times of switching and integration parameters were stored in an instrument memory file (user table) and thus high precision in the measurements was achieved.
Thin‐layer adsorption chromatography with mixed mobile phases. 3. Correlation between parameters characterizing the chromatographic systems with binary and ternary mobile phases
Authors: Rózyło J. K. , Jaroniec M. , Kolodziejczyk H. , Jaroniec J. A. , Gross J. 
Published: May 2005

AbstractTLC experimental data have been measured for polycyclic hydrocarbons in binary and ternary mobile phases on silica gel. These data have been interpretated using the equation discussed by us in Part 1 of this series [HRC & CC 2 (1979) 236]. The heterogeneity parameter appearing in this equation has been evaluated and compared for different ternary and binary mobile phases.
Thin‐layer chromatographic and high‐performance thin‐layer chromatographic ready‐for‐use layers with lipophilic modifications
Authors: Halpaap H. , Krebs K.‐F. , Hauck H. E. 
Published: May 2005

AbstractStable silica gel sorbents with aliphatic or aromatic groups are formed by chemical modifications of the silanol groups with special reactive silanes. Various lipophilic surface modifications on silica gels with varying pore structures are tested with regard to their chemical and physico‐chemical characteristics, their wettability and their chromatographic retention data. The main problem in TLC is the preparation of abrasion‐resistant layers on glass or on foils which meet the usual high standard of quality and are also suited for quantitative determinations. Thin‐layer chromatography on reversed‐phase layers can only be performed if the complete wettability of the lipophilic stationary phase in dry form is guaranteed by the mobile phase. Adsorption‐chromatographic separations with lipophilic eluents and reversed‐phase partition‐chromatographic separations with hydrophilic eluents are performed, for example, with dyes, with polycyclic aromatic hydrocarbons and with lipids. The great differences in selectivity caused by the various modifications of the sorbent and the varying eluent composition are remarkable. Ready‐for‐use layers with lipophilic surface modifications complement the existing range of pre‐coated layers and thus widen the application of TLC and HPTLC considerably.
High temperature silylation of glass capillary columns
Authors: Godefroot M. , Van Roelenbosch M. , Verstappe M. , Sandra P. , Verzele M. 
Published: May 2005

AbstractThis paper describes the results of a study on the deactivation of the surface of glass capillary columns by high temperature silylation (HTS). The different steps, leaching, washing, dehydration and HTS were optimized. A practical procedure yielding a high percentage of very good columns is given. The influence of leaching and HTS on the temperature stability and coating efficiency of capillary columns coated with OV‐1 was studied. The inertness of the glass surface after HTS is demonstrated by several examples.
Resolution of complex wax ester mixtures by glass capillary GC
Authors: Geigert J. , Dalietos D. , Neidleman S. L. 
Published: May 2005

AbstractA glass capillary GC method providing high resolution analysis of complex wax ester mixtures is described. The two key parameters needed for evaluating a wax ester mixture for industrial utility – the total carbon chain length and the number of carbon‐carbon double bonds present in each component – are simply and rapidly obtained by this method.
Group‐type analysis of gasoline range materials by high performance liquid chromatography
Authors: Jinno Kiyokatsu , Nomura Hitoshi , Hirata Yukio 
Published: May 2005

AbstractHydrocarbon group‐type analysis of gasoline‐range materials is a very important method for evaluating feedstocks and products in the petroleum industry. In this paper the method of group‐type analysis of gasoline‐range materials by high performance liquid chromatography is investigated.The results demonstrte that the separation of saturates and olefins can be accomplished with reactivated and cooled columns. The low‐temperature columns and the use of n‐hexane as an eluent play a particularly important role in the improvement of the separation.
Determination of carboxylic acids and phenols in water by extractive alkylation using pentafluorobenzylation, glass capillary GC and electron capture detection
Authors: Fogelqvist Elisabet , Josefsson Bjørn , Roos Claes 
Published: May 2005

AbstractA method is presented for the simultaneous determination of a wide range of carboxylic acids and phenols in water. Extractive alkylation is used with the tetrabutylammonium ion as counter ion and pentafluorobenzylbromide as alkylating agent. Extracts are analyzed by glass capillary gas chromatography and electron capture detection. Using one ml of water sample, the detection limit lies in the range of 1–10 μg/l. Application has been made to the analysis of steam condensate and domestic sewage effluent.
Determination of the diastereomers of vitamin K1
Authors: Vecchi M. , Schmid M. , Walther W. , Gerber F. 
Published: May 2005

AbstractA method is described for the gas‐chromatographic determination of the diastereomers of vitamin K1 (phylloquinone) in the form of their dihydro dimethyl ethers. The reported method of derivatization and chromatographic analysis in conjunction with optical rotation measurements are useful approaches for characterization of vitamin K1 samples with respect to their origin.
Determination of midazolam and its α‐hydroxy metabolite in plasma by gas chromatography with electron capture detection
Authors: Heizmann P. , von Alten R. 
Published: May 2005

AbstractA sensitive GC‐ECD assay has been developed for the simultaneous determination of midazolam (I) and its α‐hydroxy metabolite (II) in plasma. The assay involves extraction of both compounds into ether at alkaline pH (pH 12), followed by silylation of the α‐hydroxy metabolite with N,O‐bis(trimethylsilyl) trifluoroacetamide (BSTFA). On extracting 0.5 ml of plasma, the sensitivity limits are 4ng/ml for I and 3ng/ml for II. If present, the minor urinary metabolites, the 4‐hydroxy (III) and the α,4‐dihydroxy compound (IV), can also be determined by this method.
Improved separation of glycosylated tryptic peptides by RP‐HPLC
Authors: Basak S. , Compans R. W. 
Published: May 2005

AbstractThe potential of reverse‐phase high‐performance liquid chromatography (RP‐HPLC) for the separation of the tryptic glycopeptides of the hemagglutinin (HA) glycoprotein of influenza virus has been investigated. Excellent separation was accomplished with sample recovery of at least 90‐95% by the utilization of an octadecasilyl silica stationary phase and a phosphoric acid/n‐propanol solvent system. Eight glycosylated tryptic peptide classes were resolved from the HA glycoprotein of the A/USSR/90/77 virus strain.
Separation of pesticides by capillary gas chromatography. Part 2: Organophosphorus insecticides
Authors: Wolf M. , Deleu R. , Copin A. 
Published: May 2005

AbstractThis article considers the separation of 23 organophosphorus insecticides to which two metabolites have been added. The high resolution of the column permits detection of the Z and E isomers of three of these insecticides.
Fused silica capillary column GC/MS for the analysis of priority pollutants
Authors: Sauter A. D. , Betowski L. D. , Smith T. R. , Strickler V. A. , Beimer R. G. , Colby B. N. , Wilkinson J. E. 
Published: May 2005

AbstractOperational characteristics have been determined for fused silica capillary column (FSCC) GC/MS as applied to “extractable” priority polutants. Chromatographic data show excellent relative retention time (RRT) intralaboratory precision and interlaboratory accuracy when multiple internal standards are empolyed. Potential chromatographic problems, such as column overload and “double peaking”, are addressed. Response factor relative standard deviations (RSD) at 50 ng for most of the extractable priority pollutants over the long term indicated precise determination (i.e. RSD generally ≤ 10%). Linearity was demonstrated over two orders of magnitude for FSCC GC/MS analysis of compounds with relatively low and high RF (response factor) values. Potential quantitative problems, such as saturation, are discussed. For certain aromatic priority pollutants interlaboratory RF agreement was observed. This was noted as perhaps the most important property of FSCC GC/MS analysis when the multiple internal standard approach is utilized. Determinations of extractable priority pollutants are directly compared for paced column GC/MS and FSCC GC/MS analysis of separate and composited extracts. For six extracts analyzed in triplicate, the latter configuration was shown to produce more consistent results. In view of the superior analysis logistics of composite extract FSCC GC/MS analysis, this approach was established as the preferred method for the analysis of priority pollutants classified as extractable.
Simultaneous detection of total and halogenated hydrocarbons in complex environmental samples
Authors: Dahlgran James R. 
Published: May 2005

AbstractA state‐of‐the‐art gas chromatographic system for automatic simultaneous detection of halogenated and normal hydrocarbons has been developed, which consists of a standard Hewlett‐Packard 5880 with a fused silica capillary column, whose effluent is split between the standard flame ionization detector and a Tracor Hall electroconductivity detector. The system provedes excellent capillary chromatography results and high sensitivity for halogenated compounds (a detection limit of 1 ppm Archlor 1254 in fuel oil). Reliability has been provides in the daily analysis of complex environmental samples.Emergency response cleanup and the containment of hazardous chemical spills and chemical dump sites forces one to deal with samples that are very complex. The contain large numbers of naturally occurring organic compounds and varying types of organic pollutants. Capillary chromatographic techniques of gas chromatographic and gas chromatographic/mass spectrometric analyses are necessary to achieve the resolution required for the analysis of these samples.
Thin‐layer chromatography with high‐boiling mobile phases.1. Investigation of the flow of the high‐boiling mobile phases
Authors: Berezkin V. G. , Bolotov S. L. 
Published: May 2005

AbstractThis paper considers some aspects of a new TLC technique using a molten mobile phase which is solid under ambient conditions. The flow of high‐boiling mobile phase at elevated temperature in thin‐layer chromatography has been investigated and it is shown that the equation Zf2 = kt is not applicable to migration of the high boiling mobile phase front. The flow stability of the high‐boiling mobile phase is noted. It is suggested on the basis of studies of concentration profiles of the solidified mobile phases by scanning photometers that the shape of the mobile phase concentration profile be taken into account in calculation of Rf Values.
An approach to the prediction of retention times in liquid chromatography
Authors: Hanai T. , Tran C. , Hubert J. 
Published: May 2005

AbstractThe utility of Rekker's hydrophobic fragmental constant has been examined for optimization of reversed‐phase mode liquid chromatographic separations. The chromatographic behavior of about 60 non‐ionic compounds was measured in different acetonitrile/water mixtures and the logarithm of their capacity factors (log k) was correlated with their calculated hydrophobicities (log P). Linear relations were found in each case between log k and log P. The slope of the various lines was related to the percentage concentration of acetonitrile in the mobile phase. It was shown that, by using nine stand ard compounds and measuring their capacity factors in five eluents with different acetonitrile concentrations, the retention time could be predicted for 60 compounds. Calculation of the concentration of the organic modifier was also possible in a system of well coated octadecyl bonded packings with acetonitrile/water mixtures as eluent. Prediction of the capacity factor was accomplished to within 5% error.
High performance liquid chromatography/video fluorometry. Part I: Instrumentation
Authors: Fogarty M. P. , Shelly D. C. , Warner I. M. 
Published: May 2005

AbstractA rapid scanning, two‐dimensional fluorometer has been used to obtain Emission‐Excitation Matrices (EEMs) of the effluent of an HPLC column. These spectra, obtained “on the fly”, provide qualitative as well as quantitative information about unknown samples. An in‐depth discussion of the instrumentation developed and an account of data processing alternatives are presented.
Analysis of light hydrocarbons C1–C5 with Porous Layer Open Tubular fused silica columns of aluminum oxide. Part 1: The column
Authors: de Nijs R. C. M. 
Published: May 2005

AbstractA method is described for the preparation of a Porous Layer Open Tubular (PLOT) fused silica column coated with submicron particles of aluminum oxide for the analysis of light hydrocarbons. The column is thermally stable and provides reproducible analytical data over a long period of time. The column can be operated at temperatures easily controlled by commercially available gas chromatographic apparatus. 1,3‐Butadiene is retarded much more than its principal impurities: thus the polarity of aluminum oxide is extremely useful for butadiene analysis because none of the contaminants is obscured by the butadiene peak. The analysis of the 16 most common C1–C4 hydrocarbons is achieved within 5 min at 60°C with helium as the carrier gas. Conditioning of the carrier gas with water vapor from CuSO4.5H2O to decrease the activity of the aluminum oxide is described. Some applications of a 30 m × 0.32 mm aluminum oxide PLOT column are given.
Interlaboratory GC/MS response factor precision
Authors: Sauter A. D. , Mills P. E. , Fitch W. L. , Dyer R. 
Published: May 2005

AbstractA quality control procedure for Fused Silica Capillary Column Gas Chromatography/Mass Spectroscopy (FSCC GC/MS) was tested and shown to produce similar response factors at five Spectroscopy (FSCC GC/MS) was tested and shown to produce similar response factors at five laboratories. The average relative standard deviation (RSD) of interlaboratory response factors for fifty three compounds of environmental interest determined at each laboratory at nominal injected weights of 20, 100, and 200 ng was found to be 18.9% for four of the five laboratories which participated in this work. These data demonstrate that similar response factors can be attained in routine GC/MS measurements when adequate quality control is maintained.