bluuebunny/crossref_metadata_2025 huggingface dataset:
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

A 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.
All‐glass open‐split interface for capillary GC/MS
Authors: Hurley Rupert B.
Published: May 2005

This paper describes a design for an all‐glass GC/MS interface. The design has advantages due to low dead volume, lack of column effluent adsorption and degradation, simple interface production and installation, and ease of column mounting/dismounting.
Quantitative densitometric determination of reserpine and ajmaline in Rauwolfia Vomitoria by HPTLC
Authors: Katič M. , Kušan E. , Prošek M. , Bano M.
Published: May 2005

A 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

Methanol, 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

TLC 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

Stable 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

This 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

A 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

Hydrocarbon 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

A 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.
Simple apparatus for size fractionation of particles by hydrodynamic elutriation
Authors: Larsen Per , Schou Ole
Published: May 2005

A method is described for separating column packing materials into series of products of any desired narrow particle size distributions.
Determination of the diastereomers of vitamin K1
Authors: Vecchi M. , Schmid M. , Walther W. , Gerber F.
Published: May 2005

A 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

A 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

The 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

This 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

Operational 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

A 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

This 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

The 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.
Error introduced into determination of pore size distribution by size exclusion chromatography
Authors: Schou Ole , Larsen Per
Published: May 2005

Simultaneous use of large standard molecules and small particles of the product examined gives rise to errors in pore size determination by size exclusion chromatography. This error is calculated for packings of spherical particles, thus making corrections possible.
High performance liquid chromatography/video fluorometry. Part I: Instrumentation
Authors: Fogarty M. P. , Shelly D. C. , Warner I. M.
Published: May 2005

A 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

A 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

A 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.
Determination of midazolam and its major hydroxy metabolite in plasma by gas liquid chromatography. Application to a pharmacokinetic study
Authors: Coassolo P. , Aubert C. , Sumirtapura Y. , Cano J. P.
Published: May 2005

A sensitive gas liquid chromatographic (GLC) assay was developed for plasma determinations of 8‐chloro‐6‐(2′ ‐fluorophenyl)‐1‐methyl‐4H‐imidazo[1,5 α][1,4]benzodiazepine (compound I) and its hydroxymethylimidazo metabolite (compound II). The internal standards used were 8‐chloro‐6‐(2′ ‐chlorophenyl)‐1 ‐methyl‐4H‐imidazo[1,5 α][1,4]benzodiazepine (compound VI) and 7‐chloro‐5‐(2′ ‐fluorophenyl)‐1, 3‐dihydro‐1‐(hydroxyethyl)‐2H‐1,4‐benzodiazepin‐2‐one (compound VII) for compounds I and II, respectively. Following extraction, and silylation for compound II, compounds I and II were analyzed by GLC using a glass column packed with 5% OV‐101 on Gas‐Chrom Q, and a 63Ni electron‐capture detector. The GLC method was validated by a CI‐GC/MS technique. The detection limit of the assay is approximately 4–5 ng/ml for compound I and 3 ng/ml for compound II. The method was used in comparative pharmacokinetic studies of the distribution of the two compounds in arterial and venous blood.
Qualitative evaluation of aromatic herbs by direct headspace GC analysis. Applications of the method and comparison with the traditional analysis of essential oils
Authors: Chialva F. , Gabri G. , Liddle P. A. P. , Ulian F.
Published: May 2005

GC headspace analyses of various aromatizing herbs have been compared with those relating to the essential oils, obtained by steam distillation, of the same plants. In this way it was possible to establish the most significant differences between the composition of a herb flavor and that of its essential oil. In particular, we observed some very volatile compounds in the headspace samples which were absent from the essential oil; these components may make an important contribution to the herb flavor. The identification of these substances is still in progress.
Applications of heart cutting from packed to capillary columns
Authors: Phillips R. J. , Knauss K. A. , Freeman R. R.
Published: May 2005

The power of capillary gas chromatography can be enhanced by selective fractionation of the sample. One way of doing this is heart cutting from a packed gas chromatographic column. This paper describes modification of a commercial instrument for such separations. Components of the system include an automated Deans switch and an electrically heated trap. The benefits of this arrangement are illustrated with chromatograms of naphtha, urinary aromatic acids, and wine volatiles.
Trace analysis of halocarbons in water; Direct aqueous injection with electron capture detection
Authors: Grob K. , Habich A.
Published: May 2005

Interest in monitoring halogenated organics in drinking water and natural surface and ground water in the low ppb range continues to grow. There is a tendency to include still more volatile halocarbons, the trace determination of which is known to be rather demanding. This prompted us to re‐examine the feasibility of large‐volume direct aqueous injection onto capillary columns, coupled with ECD. A primary problem was to avoid simultaneous elution of water with halocarbons, since water suppresses the ground current of the ECD. The following measures contributed to the solution of this problem.

Apolar, extremely inert, columns are required to elute water completely, and even before very light halocarbons. Their coatings have to be far thicker (≈︁ 5 mUm) than commonly employed thick films since they must permit isothermal analysis at a column temperature around 100°C in order to ensure rapid and complete elution of water. Finally, it is essential that sampling be carried out on‐column for two reasons: diffusion of water vapor in the injector, resulting in delayed elution, is then eliminated, and peak distortion during splitless injection is avoided.

Although we now know that persilylated columns with immobilized coatings withstand routine water injections, more longterm experience is needed to provide detailed recommendations for the handling of these columns.
Dynamic leaching of sodium‐glass capillary columns
Authors: Venema A. , Sukkel J. T. , Kampstra N.
Published: May 2005

It is well known that removal of metal ions from the glass surface greatly improves both the thermal stability and the adsorption characteristics of glass capillary columns. Usually metal ions are removed from a glass surface by acid leaching; in particular, the static leaching procedure with hydrochloric acid is used very often for the preparation of glass capillary columns. This paper discusses the results of an investigation into dynamic leaching. Special attention is paid to those factors which affect the adsorption properties of the leached surface. The importance of the non‐specific adsorptivity of the capillary surface due to changes of surface properties induced by the leaching process is pointed out.
Heliflex chirasil‐Val; GC of amino acid enantiomers
Authors: Abe I. , Kuramoto S. , Musha S.
Published: May 2005

Heliflex Chirasil‐Val, a modified form of the original Chirasil‐Val phase coated on fused silica capillary, has been investigated with regard to its resolution efficiency and the separation profile for various enantiomeric derivatives of amino acid. The best results could be obtained with TFA‐Et derivatives by reason of the relatively low column temperature required.
Organic micropollutants in the sewage from a phenoxyalkanoic acid production plant after biological treatment in a municipal trickling filters plant
Authors: Folke Jens
Published: May 2005

The environmentally hazardous organic substances in the waste water from the manufacture of chlorophenoxyalkanoic acids have been identified and semiquantified before and after passing through a biological treatment plant for municipal sewage, the secondary effluent of which is discharged into a marine ecosystem. The organics belong to three groups: (i) chlorophenols; (ii) chlorophenoxyalkanoic acids; and (iii) chlorinated neutrals. The removal of chlorophenols and phenoxyalkanoic acids was shown to be good, with a 90% overall reduction of chlorinated substances in the sewage passing through the treatment plant. The lowest reduction occurred for the polychlorinated compounds. Two chlorobenzofurans among the chlorinated neutrals were preliminarily identified.
HPLC, mass spectrometry, and LC/MS of gossypol and its derivatives
Authors: Martlin S. A. , Zhou R. H. , Games D. E. , Jones A. , Ramsey E. D.
Published: May 2005

Conditions are reported for the reverse‐phase HPLC analysis of gossypol and of some of its derivatives, including anhydrogossypol, gossypolone, gossypol hexaacetate, and Schiff's base derivatives. It is shown that field desorption (FD) and chemical ionization (CI) mass spectrometry have advantages over electron impact (EI) mass spectrometry for the characterization of these compounds and that combined high‐performance liquid chromatography/mass spectrometry (LC/MS), especially when used in the CI mode, is particularly effective.
Multilayer effects in liquid adsorption chromatography with mixed mobile phases
Authors: Borówko M. , Jaroniec M.
Published: May 2005

This paper describes the theory of liquid adsorption chromatography (LSC) with mixed mobile phase, involving formation of multilayer surface phases. An equation describing the dependence of the capacity ratio upon the mobile phase composition is derived and theoretical curves illustrating the same dependence are calculated accordingly by assuming different thicknesses of the surface phase.
The role of column technology in capillary gas chromatography
Authors: Grob K.
Published: May 2005

After having witnessed, over a period of more than 20 years, the extremely difficult early development of capillary gas chromatography, the growth of scientific understandign, and finally its sudden blossoming into a commonly accepted technique, the author is confronted with a dichotomy. On the one hand, there are the dramatic advances in the fields of column preparation, and of sampling techniques. Implementation of these advances should logically result in correspondingly drastic progress in the average quality of application work in drastic progress in the average quality of application work in capillary gas chromatography. On the other hand, however, such progress is lacking. The greater the practical potential, the smaller the fractionm of that potential which is practically exploited. The reason is that most users interpret te recent advances as exempting them from their obligation to know and think about the many details of practical work, and to attempt standardized work with standard columns and techniques. Standardization of routine work is beneficial, provided the standards are optimized‐a condition which all too often remains unfulfilled. Research work, performed in a realm of ever new and unknown conditions, is of poor quality when done by standardized means. Since the most critical part of optimization is column selection, the capillary column must be mastered as a familiar tool in the hands of the investigator. This is hardly possible in the absence of any direct contact with column technology.
Analysis of gases containing inorganic compounds and light hydrocarbons on fused‐silica open‐tubular columns prepared with a thick liquid phase film
Authors: Palo R. T. , Walters J. D. , March E. W. , Ettre L. S.
Published: May 2005

Capillary columns having a thick liquid phase film and a low phase ratio permit the separation of low molecular mass compounds which would have a very small capacity factor on columns with a classical thin film. At the same time, the increased sample capacity allows conventional hot‐wire thermal conductivity detectors to be used with such columns. The analysis of natural and refinery gases, containing both inorganic compounds and light (C1C7) hydrocarbons, utilizing a combination of hot‐wire and flame ionization detectors, is demonstrated.
The optimized separation of aromatic carboxylic acids by HPLC
Authors: Patel B. , Purnell J. H. , Wellington C. A.
Published: May 2005

The optimization of the separation of eight aromatic carboxylic acids, using Hypersil SAS and MOS reverse phase columns, with respect to eluent (methanol : water) composition, pH, and temperature, is described. Window diagram techniques are used and the pH of the aqueous buffer and elution temperature are shown to be more critical than eluent composition.
Optimization of capillary parameters for gas chromatography
Authors: Ogan K. , Scott R. P. W.
Published: May 2005

An HETP equation for the capillary column is developed that takes into account the dependence of gaseous diffusion on pressure, the compressibility of the mobile phase, together with the unique relationship between mobile phase velocity, and the resistance to mass transfer in the stationary phase. The equation is used to develop a procedure for column optimization and expressions are derived that allow the optimum column radius and optimum column length to be calculated for a given fixed inlet pressure. It is shown that fast, simple separations are optimally achieved using relatively short small diameter columns. Conversely, optimum performance for the separation of complex mixtures requiring higher efficiencies requires the use of long columns with relatively large diameters.
Determination of nitrated‐polyaromatic hydrocarbons (nitro‐PAHs) in environmental samples by high resolution chromatographic techniques
Authors: Liberti A. , Ciccioli P. , Cecinato A. , Brancaleoni E. , Di Palo C.
Published: May 2005

An analytical procedure is described for the fractionation of organic compounds present in environmental samples and the determination of nitro polyaromatic hydrocarbons (nitro‐PAHs). Both low and high resolution liquid chromatography are employed for the prefractionation of the soluble organic fraction (SOF) extracted from particulate matter or gaseous pollutants collected on adsorption traps. High resolution gas chromatography is used to analyze four fractions containing alkanes, PAHs, nitro‐PAHs, and other polar PAHs. Nitrogen‐containing species are separated by GC and detected specifically using an alkali flame (NPD) detector. Flame ionization (FID) detection, GC‐MS of positive ions, and negative ion chemical ionization MS of the whole fraction is used for the identification and quantitation of the various components. The composition of SOF extracted from particulate matter emitted from diesel exhausts is elucidated and a large number of nitro‐PAHs identified by the combination of the various techniques.
Enantiomeric separation of halocarboxylic acids by capillary gas chromatography
Authors: Koch E. , Nicholson G. J. , Bayer E.
Published: May 2005

The direct determination of the enantiomeric purity of halocarboxylic acids is described. The method used involves gas chromatographic separation of the corresponding tert‐butylamides on deactivated glass or fused‐silica capillaries coated with Chirasil‐Val. Both the influence of the amide moiety on enantiomeric resolution and tailing, and the racemization during formation of the amide derivatives were studied.
The determination of serum retinol by high performance liquid chromatography
Authors: Woollard G. A. , Woollard D. C.
Published: May 2005

A method for the quantitation of retinol in serum by normal phase high performance liquid chromatography is described. The mobile phase consists of a hexane/diethylether/methanol mixture with spectrophotometric detection. The sample preparation is similar to that described by other authors and involves protein precipitation followed by extraction and direct injection onto the chromatograph. Adequate sensitivity is achieved using 200 μl samples. The internal standard chosen is α‐naphthol because of its spectral similarities to retinol and its greater stability than the commonly used retinyl esters. The method has been successfully applied to the clinical evaluation of a number of malabsorption syndromes for which it is preferred to the measurement of total carotenoids.
Quantitative determination of phospholipids in mitochondria using HPTLC and fluorimetric assay in situ
Authors: Wollbeck D. , Kleist E. v. , Elmadfa I. , Funk W.
Published: May 2005

A method is described for quantitative determination of phospholipids of mitochondria following one‐dimensional thin‐layer chromatography without previous elution. Using high performance thin‐layer chromatography (HPTLC) and an in situ fluorescence technique, the time needed for quantitative determination is relatively short. As the method is rather sensitive, small amounts of the extracts can be applied (about 200 ng of total phospholipids per spot). The reproducibility for the phospholipid fractions determined was in the range of 8–17%. The procedure was tested with lipid extracts of rat liver mitochondria. The method allows the determination of cardiolipin, phosphatidyl ethanolamine, phosphatidyl inositol, phosphatidyl choline, and sphingomyelin.
Gas chromatographic separation of sugars by on‐column injection on glass capillary columns
Authors: Traitler H. , Del Vedovo S. , Schweizer T. F.
Published: May 2005

Sugars were separated gas chromatographically on short apolar glass capillary columns by using cold, on‐column injection (OCI) techniques. After silylation, oligomers up to the hexasaccharides could be efficiently separated in resonable retention times. Response factors of silylated sugars were determined as a function of varying sample amounts and concentrations. The optimum injection amount was found to be 1 μl in heptane as solvent.
Construction and application of a cold on‐column injection system for capillary gas chromatography
Authors: Arrendale R. F. , Chortyk O. T.
Published: May 2005

A cold on‐column injection system for capillary gas chromatography (GC) applications was constructed. It was based upon a conventional split/splitless capillary GC inlet, which in turn was a modification of a conventional packed GC column inlet. The heart of the laboratory constructed cold on‐column inlet design was a disposable pyrex micro‐sampling pipet, which functioned as a needle guide for sample injection. The sample was injected through a traditional GC septum. Construction of the injection system is described and applications are illustrated by separations of a variety of complex mixtures.
Non‐linear effects of TMS capping on dimethyloctyl HPLC stationary phases
Authors: Tomellini S. A. , Hsu Shih‐Hsien , Fazio S. D. , Hartwick R. A.
Published: May 2005

Co‐bonding ligands on the same support to produce “blended” HPLC stationary phases is most commonly carried out in the form of capped reversed‐phase materials. Non‐additive retention properties were observed over a range of trimethylsilane/dimethyloctylsilane ratios. In addition, the increase in retention per mole of bonded trimethylsilane was greatest at the highest dimethyloctylsilane coverages.
Direct determination of the phenanthrene and methylphenanthrene isomer distribution in crude oils by multidimensional capillary GC
Authors: Schomburg G. , Weeke F. , Schaefer R. G.
Published: May 2005

The methylphenanthrene index (MPI) [1,2] which was recognized as suitable for the assessment of the “thermal” history of sedimentary organic matter, can be determined directly i.e. without preceding LC group separations by application of multi‐dimensional GC in capillary columns. A GC double oven instrument (Siemens Sichromat 2) equipped with a “live switching” coupling piece was used for the necessary measurements.
Capillary zone electrophoresis: Effect of physical parameters on separation efficiency and quantitation
Authors: Lukacs K. D. , Jorgenson J. W.
Published: May 2005

Separation efficiency in capillary zone electrophoresis was examined as a function of capillary length and diameter as well as solute concentration for a borosilicate glass capillary/phosphate buffer system. Electroosmotic flow coefficients in borosilicate, fused silica, and teflon capillaries were measured over the useful operating pH range of 3–8 at constant applied power (0.333 W). Sample introduction by a simple, low‐dispersion electromigration method was found to be a reliable procedure for solute quantitation.
Quantitative gas chromatography using a new automated derivatizer
Authors: Frank H. , Gerhardt J. , Nicholson G. J.
Published: May 2005

In the gas chromatographic analysis of complex biological samples, the most time‐consuming and error‐prone steps are the pretreatment required for isolation and purification of the compounds of interest and, for most analytes, the derivatization to chemically and thermally stable compounds with high volatility. These wet‐chemical steps are usually carried out manually, and for routine analysis of large numbers of samples they are often rate‐limiting. A dedicated automated derivatizer has been constructed, the employment of which significantly reduces the time required for manual labor and increases the reproducibility of derivatization and hence the accuracy of analysis.
Capillary GC of triglycerides in fats and oils using a high temperature phenylmethylsilicone stationary phase, part I
Authors: Geeraert E. , Sandra P.
Published: May 2005

The analysis of triglycerides on FSOT columns coated with a phenylmethylsilicone gum opens up new perspectives in fat and oil characterization. On phenylmethylsilicone, besides a “carbon number” or CN separation, the triglycerides are also separated according to the different combinations of saturated and unsaturated fatty acids in the triglycerides.
Application of capillary gas chromatography with electron capture detection and split‐splitless injection to the evaluation of volatile halogenated hydrocarbon removal using hydrogen peroxide after break‐point chlorination in drinking water treatment
Authors: Peruzzi P. , Cursi D. , Griffini O.
Published: May 2005

In this paper we report a way to evaluate the removal of volatile halogenated hydrocarbons formed after break‐point chlorination in the Arno river raw water at the Mantignano Utility, Florence, Italy, following dechlorination by hydrogen peroxide. The removal evaluation is performed by GC‐ECD on fused silica capillary columns with split‐splitless injection on n‐pentane extracts and by other analytical techniques such as UV254 absorption, TOC and TOX. Both laboratory and pilot plant data on Arno river raw water are reported and discussed.
Interlaboratory studies of the determination of selected chlorobiphenyl congeners with capillary gas chromatography using splitless‐ and on‐column injection techniques
Authors: Tuinstra L. G. M. Th. , Roos A. H. , Griepink B. , Wells D. E.
Published: May 2005

The Community Bureau of Reference has organized a collaborative interlaboratory project to improve the analytical protocol for some specific chlorobiphenyls (CBs) within the European Community (EC). A series of test procedures were prescribed to optimize the gas chromatographic conditions for splitless and on‐column injection, which substantially improved the quality of data. Important parameters included the initial column and injector temperatures and the choice of the polarity of the stationary phase. In a study with cleaned eel‐fat extracts, coefficients of variation for reproducibility CV(R) ranging from 11 to 24% at the 0.04–0.3 mg/kg level per CB congener were obtained. No significant difference could be found between splitless‐ and on‐column injection.
Evaluation of smectic biphenylcarboxylate ester liquid‐crystalline polysiloxane stationary phases for capillary column gas chromatography
Authors: Markides K. E. , Chang H‐C. , Schregenberger C. M. , Tarbet B. J. , Bradshaw J. S. , Lee M. L.
Published: May 2005

Mesomorphic biphenylcarboxylate esters were coupled via flexible aliphatic hydrocarbon spacers to a polysiloxane backbone. The influence of spacer length, percent mesomorphic substitution, and crosslinking of the stationary phase on liquid‐crystalline transition temperatures and on chromatographic performance was investigated. Unique selectivity and good efficiency over a wide temperature range for gum and cross‐linked liquid‐crystalline phases were demonstrated by the separation of various isomeric polycyclic aromatic compounds.
Some applications of capillary gas chromatography in the chemical industry
Authors: van Straten A. J.
Published: May 2005

About three years ago, fused silica capillary columns were introduced in the Quality Control Laboratory of the Shell refinery/chemical complex at Pernis. In general, long, thick‐film, wide‐bore capillary columns are used together with low split ratios and hydrogen as carrier gas. These conditions enable the analysis of relatively large sample amounts, resulting in low detection limits for the minor components without overloading by the major components, while still maintaining a satisfactory resolution. A number of applications are shown, such as the analysis of complex mixtures, the determination of trace impurities and the analysis of residual volatiles in polymers.
Study of peak profiles in nonlinear gas chromatography: Application to the peak distortions observed with overloaded capillary columns
Authors: Cardot P. , Ignatiadis I. , Jaulmes A. , Vidal‐Madjar C. , Guiochon G.
Published: May 2005

The elution profiles observed with overloaded capillary columns are well described by a four‐parameter theoretical model derived from the basic mass balance equations which relies on an expansion of the partition isotherm to the second term and takes the sorption effect into account. The reliability of the model is demonstrated by the fact that the peak leaning coefficient obtained from a least squares fit of the model to the experimental peak is in good agreement with that obtained from the variation of peak height with retention time at peak maximum. The coefficeint of apparent axial dispersion is independent of sample size and can be used to characterize the plate height at zero concentration of an overloaded capillary column.
Paul Schuftan and the early development of gas‐adsorption chromatography
Authors: Arnold G. , Berezkin V. G. , Ettre L. S.
Published: May 2005

The life and activities of Paul Schuftan, a pioneer in gas‐adsorption chromatography are discussed and placed in the context of the early evolution of gas chromatography.
Distribution of weight, density, and molecular weight in crude oil derived from computerized capillary GC analysis
Authors: Osjord E. H. , Rønningsen H. P. , Tau L.
Published: May 2005

Chromatographic separation of crude oil components has been performed on a 50 m Chrompack Sil 5 fused silica capillary column, temperature programmed from 10 to 300°C. Approximately 70 peaks eluting before n‐nonane (n‐C9) and all normal paraffins to n‐C19 were identified by a retention time table. Peak areas were converted to weight % using 1‐heptene as internal standard and relative response factors. Components were divided into boiling range groups from n‐C6 to n‐C19. Paraffinic, naphthenic, and aromatic distributions were obtained for the boiling point fractions up to n‐C9.

Group average densities and molecular weights were calculated from pure component properties up to n‐C9. Knowing the density and molecular weight as functions of boiling range group to n‐C9, these functions can be extrapolated to n‐C19, based on data and correlations from more than 20 distillations of paraffinic North Sea oils adn condensates. The densities and molecular weights of the C10+ and the C20+ residues were calculated to satisfy a balance of weight, volume, and number of moles for the whole sample.

Measurements on the residues were used to cross‐evaluate the GC method against distillation. The difference in weight was estimated to be less than ± 0.5% in absolute terms for the C10+ residue. The corresponding figure for C20+ was ± 2%. Relatively, calculated densities are within ± 1%, molecular weights within ± 2% compared to direct measurements. Calculations were performed by a BASIC program in a GC interfaced computer.
Automatic simulated distillation of heavy petroleum fractions up to 800°C TBP by capillary gas chromatography. Part I: Possibilities and limits of the method
Authors: Trestianu S. , Zilioli G. , Sironi A. , Saravalle C. , Munari F. , Galli M. , Gaspar G. , Colin J. M. , Jovelin J. L.
Published: May 2005

The characterization of heavy petroleum fractions is essential for the design and improvement of cracking plants converting heavy feedstock into valuable “white” products. Conventional simulated distillation methods using packed columns are unsuitable for this purposes, being limited to boiling points up to about 600°C. The method presented is able to cover a boiling points interval ranging from about 150°C up to around 800°C. It employs a short, nonpolar, highly thermostable capillary column routinely operated at temperatures around 430°C. The analytical system is based on a high temperature versions of a fully automatic, capillary dedicated gas chromatograph. The experimental data demonstrate that cold on‐column injection is the sole sampling system suitable for such heavy compounds. The conversion of the retention times into boiling points, based on the use of low molecular weight polyethylenes, is extremely reliable, as demonstrated by the excellent retention time reproducibilities. The lower part (up to 550–600°C TBP) of the boiling point distribution curves of heavy petroleum fractions obtained on capillary columns fits well with the corresponding distribution curves based on packed column data. For the petroleum fractions fully eluted from the column the quantitative results obtained either using internal standards or by direct processing of the elution curves are in excellent agreement (less than 0.3 weight% differences). The method has been applied to the determination of the true boiling points corresponding to short path vacuum distillation (DISTACT) cut points over 300°C.
The autoderivatization of 4‐ketocyclophosphamide during capillary gas chromatography
Authors: de Bruijn E. A. , Leclercq P. A. , Tjaden U. R.
Published: May 2005

The selectivity of a capillary gas chromatographic assay for the anti‐neoplastic and immunosuppressive agent cyclophosphamide (CPA) towards one of its naturally occurring metabolites, i.e. 4‐ketocyclophosphamide (4‐keto CPA), has been studied. Mass spectrometry studies showed that a cyclization product of 4‐keto‐CPA can form using the same chromatographic conditions as those under which CPA was determined. However, the amount produced is relatively small (less than 10%) compared with the percentage produced from CPA. Furthermore, both cyclization products, formed by loss of HCI and intraalkylation of the parent compounds, can be separated well under suitable chromatographic conditions.
Concurrent solvent evaporation for on‐line coupled HPLC‐HRGC
Authors: Grob K. , Walder Ch. , Schilling B.
Published: May 2005

A technique is proposed which allows introduction of very large volumes of liquid (10 ml were tested) into capillary columns equipped with short (1–2 m long) retention gaps. It is based on concurrent solvent evaporation, i.e. evaporation of the solvent during introduction of the sample. The technique presupposes high carrier gas flow rates (at least during sample introduction) and column temperatures near the solvent boiling point. The major limitation of the method is the occurrence of peak broadening for solutes eluted up to 30°, in some cases up to 100°, above the injection temperature. This is due to the absence of solvent trapping and a reduced efficiency of phase soaking. Therefore, use of volatile solvents is often advantageous. Application of the concurrent solvent evaporation technique allows introduction of liquids which do not wet the retention gap surface. However, the method is still not very attractive for analysis of aqueous or water‐containing solutions (reversed phase HPLC).
Effect of free hydroxy groups in the separation of polyglycerol esters by capillary supercritical fluid chromatography
Authors: Chester T. L. , Innis D. P.
Published: May 2005

Separations of polyglycerol esters containing 3–5 hydroxyl groups and of their silyl derivatives are demonstrated on DB‐1 and DB‐17 columns. Useful chromatograms are produced in every case. However, the chromatograms are improved on derivatization. The extent of improvement realized increases with the number of free hydroxyl groups per molecule.