bluuebunny/crossref_metadata_2025_split huggingface dataset:
Automatic sugar analysis in the beet industry. Part I: Parameter optimization of a reversed phase HPLC carbohydrate determination
Authors: Herbreteau Bernard , Lafosse Michel , Morin‐Allory Luc , Dreux Michel 
Published: May 2005

AbstractAn evaluation of the most commonly used HPLC system (reversed phase octadecyl sillica gel) was undertaken in order to determine the level of certain carbohydrates in molasses produced in the refining of sugar beet. Chromatographic parameters and purification operations prior to analysis are discussed in order to develop an analytical method permitting automation of sugar determination. A Zorbax ODS column (250 × 9.4 mm), water elution, and light scattering detection allow easy determination of glucose + fructose, sucrose, and raffinose in molasses using an internal standard (maltose).
Capillary gas chromatography of amines with ammonia as carrier gas
Authors: Abdel‐Rehim Mohamed , Hassan Moustapha , Ehrsson Hans 
Published: May 2005

AbstractThe use of ammonia as a carrier gas for the chromatography of aliphatic and aromatic amines has been investigated. As compared to nitrogen, ammonia gave drastically improved peak symmetry and lower capacity factors (k′) for primary and secondary amines on polar (Polyethylene glycol) and medium Polar (methylphenylcyanopropylsilicone) stationary Phases. The effect of ammonia was more Pronounced at low column temperatures. Considerably better detection limits of primary and secondary amines were obtained with ammonia as carrier gas than with nitrogen. No detrimental effects of using ammonia were observed on the gas chromatograph or on the columns over a period of about one year.
Charcoal open tubular traps for the analysis of air and headspace samples
Authors: Grob Konrad , Artho Anna , Frauenfelder Christine , Roth Ives 
Published: May 2005

Abstract5 cm × 0.3 mm i.d. glass capillary tubes coated with fine charcoal particles are used for the analysis of organic compounds, particularly tri‐ and tetrachloroethylene, benzene, and toluene, in air and headspace samples. Due to their small size, these traps are easy to use with capillary GC. As, e.g. 20 ml of gas can be sucked through this trap in 20 s, it is a simple technique providing high sensitivity; compared to headspace with split injection, sensitivity is increased by a factor exceeding 100. The column effluent is split into FID and ECD in such a way that small as well as large amounts of the chlorinated compounds can be detected.
Programmed cold sample introduction and multidimensional preparative capillary gas chrornatography. Part I: Introduction, design and operation of a new mass flow controlled multidimensional GC system
Authors: Rijks Jacques P. E. M. , Rijks Jacques A. 
Published: May 2005

AbstractA new design of a mass‐flow controlled multidimensional switching system for capillary gas chromatography is introduced and discussed. Large sample amounts can be introduced with a required input band width onto the first column. A combination of cold sample introduction and successive high speed programmed heating of the injector liner is used for this purpose. The potential of such an approach for selective and fast high resolution separations with series coupled wide bore, thick film columns is emphasized, and illustrated for various concentrations.
Evaluation of a microHPLC system dedictaed to packed capillary column liquid chromatography
Authors: Trisciani Adriano , Andreolini Franca 
Published: May 2005

AbstractMiniaturization and optimization of the solvent delivery system, mixing device, and detection system for gradient elution at few μl/min is the most important objective of instrumental development in microHPLC using packed capillary columns. Instrumental solutions and evaluation of the performence of a dedicated system for automatic gradient elution with packed capillary columns are reported. Retention time precision shown buy the system results in an RSD of 0.20–0.52% for a PAH model mixture eluted under gradient conditions at few μl/min. Compositional accuracy of gradient profiles is also demonstrated.
Chitosan‐based stationary phases in microcolumn liquid chromatography
Authors: Jinno Kiyokatsu , Ogura Satoshi , Takayama Katsumi 
Published: May 2005

AbstractTwo kinds of cross‐linked chitosan beads were evaluated as the stationary phase for microcolumn liquid chromatography. The phase with aminoalkyl substituent can be expected to function similarly to commonly known aminopropyl bonded phases. Separation of PAH with the chitosan phase bearing phenyl group substituents has been accomplished in the gradientelution mode with acetonitrile‐water as the mobile phase. Planarity recognition capability comparable with that of monomeric octadecylsilica phase was observed.
Optimization of conditions for high temprature capillarary gas chromatography using a split‐mode programmable temprature vaporizing injection system
Authors: Tipler Andrew , Johnson Greg 
Published: May 2005

AbstractThis paper discribes an investigation into the effects of various operating conditions applied in a PTV‐based gas chromatographic system on the performance observed in high temperature analyses. The work comprises a combination of physical and chromatographic measurements, and conclusions are drawn as to the most effective way of using the equipment under evaluation.
Microcolumn chromatography for the analysis of detergents and lubricants. Part 1: High temperature capillary gas chromatography (HT‐CGC) and capillary supercritical fluid chromatography (CSFC)
Authors: Sandra Pat , David Frank 
Published: May 2005

AbstractHigh Temperature Capillary GC and Capillary SFC have been applied to the analysis of non‐ionic lubricants, i.e. alkylphenol polyethoxylates (APnEO), ethoxylated alcohols (nEOAIc), polyethylene glycols (PEG), and ethoxylated triethanolamines (nEOEA); to the analysis of anionic lubricants, i.e. alkylbenzene‐sulfonates (ABS), alkylsulfonates (AS), and ethoxylated phosphoric acids (nEOPhA); and to the analysis of cationic lubricants, i.e. quaternary ammonium salts (Quats). Both techniques are compared in terms of resolution and analysis time. The importance of derivatization in HT‐CGC and CSFC is illustrated.
An on‐column capillary gas chromatographic method for the analysis of synthetic pyrethroid residues on fish eggs
Authors: Bolygó Elek , Hadfield Stephen T. 
Published: May 2005

AbstractA sensitive and reproducible residue method is described for the determination of cypermethrin and deltamethrin in fish eggs. The limit of determination of 0.0005 mg kg−1 is achieved using only a very small sample size; typical sample weights lie in the range of 0.1‐1 g of fathead minnow or trout eggs. The method involves tissue homogenization (tube homogenizer) followed by hot acetonitrile extraction, then sequential C8, aluminum oxide, and silica gel clean‐up. The clean‐up is carried out in glass columns using cotton wool plugs in order to minimize potential sample contamination by plasticizers. Residues are determined by capillary chromatography using automated on‐column injection with electron‐capture detection. Confirmation of residues by gas chromatography‐mass spectrometry using selected ion monitoring (SIM), is also described.
CGC enantiomer separation on diluted cyclodextrin derivatives coated on fused silica columns
Authors: Schurig Volker , Jung Martin , Schmalzing Dieter , Schleimer Martin , Duvekot Jan , Buyten Jan C. , Peene Jürgen A. , Mussche Philippe 
Published: May 2005

AbstractHigh‐resolution capillary gas chromatographic separation of enantiomers, belonging to different classes of compounds on cyclodextrin derivatives is described. The solutions of heptakis (2,3,6‐O‐trimethyl)‐β‐cyclodextrin (Phase I), heptakis (2,6‐O‐dimethyl‐3‐O‐trifluoro‐acetyl)‐β‐cyclodextrin (Phase II) and heptakis (2,6‐O‐dimethyl‐3‐O‐heptafluorobutyryl)‐β‐cyclodextrin (Phase III) in the moderately polar polysiioxane OV‐1701 were coated onto deactivated fused silica capillaries furnishing columns of high efficiency. The three phases show different enantioselectivities for various racemic mixtures.
Reversed‐phase LC‐GC with a nitrogen‐phosphorus detector using a loop‐type interface combined with a sandwich‐type phase separator
Authors: van Zoonen Piet , van der Hoff G. René , Hogendoorn Elbert A. 
Published: May 2005

AbstractReversed phase LC is coupled to capillary GC by means of an on‐line extraction of the LC eluent. The extract is transferred to a loop‐type LC‐GC interface equipped with an early vapor exit. Using a phase switch from an aqueous reversed‐phase (RP)LC solvent to an organic solvent facilitates the introduction of the analyte in the GC system, since organic solvents such as hexane, pentane, and dichloromethane are more appropriate for the GC‐injection technique used in this study. As the partition coefficient of an organic solvent/aqueous system is correlated to the retention mechanism of reversed phase LC, the method has a general potential in LC/GC interfacing, viz. the extractability a component from the LC mobile phase eluting above a certain capacity factor from a RPLC column can be expected to be efficient. The method is applied to the determination of residues of the fungicide fenpropimorph in barley, oats, rye, and wheat. Another application of the interface which is feasible is the on‐line extraction of aqueous samples prior to large volume injection on GC‐NPD. The potential of the interface for the determination of residues nitrogen containing herbicides is estimated.
Determination of traces of polychlorinated biphenyls in pigments
Authors: Sistovaris Naoum , Donges Ulrich , Dudek Beate 
Published: May 2005

AbstractPCB patterns in a new pigment brand are characterized using GC‐MS in the single ion monitoring (SIM) mode. Specific PCBs are then used as external standards for GC‐ECD quantification. The following PCB isomers or groups of isomers have to be determined (CB = chlorobiphenyl): total diCBs, 3,3′ diCB, 2,4,5‐triCB, 2,2′,4,4′‐tetraCB, 2,2′,5,5′‐tetraCB, total pentaCB, total hexaCB. Capillary gas chromatography is performed on preseparated solutions (LC) of pigment. An electron caputure detector (ECD) is used for PCB detection and quantification. Calibration is based on the peak areas of external standards and the PCB isomers in the samples, all normalized for internal standard peak areas. Total concentrations of diCB, hexaCB, or pentaCB in a sample are calculated by summing the individual PCB isomer concentrations within the correcsponding elution ranges. Determination limits lie in the range of 1 mg/PCB‐isomer/kg pigment.
Liquid gas techniques for GC trace analysis
Authors: Dünges Wolfgang , Fooken Cornelia , Wagner Heinz 
Published: May 2005

AbstractLiquid gases (LG), i.e. low boiling compounds with vapor pressures below 5 bar at room temperature, are introduced as solvents for trace analyses. A system for preparin, diluting and handling LG solutions safely and conveniently in 5 to 500 μl amounts was developed as well as a syringe for direct injection of μl‐LG samples into capillary GC. Even technical grade LG are of high purity. GC/FID of LG solutions (starting at −60°C) allows the separation of volatile traces from the solvent peak: e.g., dichloromethane can be measured in the picogram range.
Highly sensitive determination of haloperidol in human serum by capillary gas chromatography using a surface ionization detector
Authors: Nagai Yumi , Arimoto Hiromi , Fujii Toshihiro 
Published: May 2005

AbstractA method has been developed for highly sensitive determination of haloperidol in human serum involving a simple extraction procedure followed by gas chromatographic separation. Target components were separated from the extracting solvents with a Van den Berg type solventless sample injector before introduction Into a DB‐1 capillary separation column. A surface ionization detector (SID), which has highly selective sensitivity for Substituted amines, was employed for quantitation using bromperidol as an internal standard. Chloroform proved to be the best extracting solvent, yielding a quantitative detection limit of 5 ng/ml (S/N = 2). Comparison of the response to target compounds obtained by the SID, FTD (flame thermionic detector), and FID (flame ionization detector) showed the SID to be superior.
Distorted solvent peaks in capillary GC: A symptom of porous column surfaces
Authors: Grob Konrad , Artho Anna 
Published: May 2005

AbstractMany uncoated precolumns, and to a lesser extent separation columns, strongly retain some of the solvent. Retarded release of such solvent elevates the baseline after the solvent peak and causes ugly “humps” of eluted solvent as the temperature is increased. The problem is probably a result of retention by a porous surface, e.g. surfaces obtained by leaching or hydrothermal treatment of capillaries prior to silylation. It is assumed that other problems with capillary columns can be explained by the same mechanism, including: a kind of adsorption including apolar compounds, and “ghost” peaks as well as “memory” effects. Fused silica capillaries are superior to glass, but even for these special procedures are required in order to achieve thorough deactivation of the internal surface without introducing porosity.
Automated analysis of volatile halogenated hydrocarbons in rainwater and ambient air by purge and trap capillary gas chromatography
Authors: Fujita Masahiko , Jung Wontae T. , Tatematu Hiroko , Sohn Donghun H. , Maeda Tsuneaki 
Published: May 2005

AbstractAn automated system employing a purge and trap technique with capillary gas chromatography and electron‐capture detection (ECD) has been developed for the analysis of trace levels of volatile halogenated hydrocarbons and applied to the determination of the compounds in environmental samples such as rainwater and ambient air. The operation of the method, its application to environmental samples, and the results obtained are described. Use of the system ensured good chromatographic resolution and high accuracy, even with trace levels of the compounds.
Supercritical fluid solid chromatography using novel porous glassy carbon. Evaluation of retention mechanisms
Authors: Engel Tina M. , Olesik Susan V. 
Published: May 2005

AbstractThe use of a porous glassy carbon (PGC) material as a packed‐column SFC stationary phase has been previously demonstrated [1]. The material is further characterized in terms of its retention characteristics. The effects of variations in mobile phase composition, pressure, and temperature conditions are evaluated. Variation of temperature and pressure yielded expected results, specifically, decreased solute capacity factors with increased mobile phase density. The choice of supercritical fluid mobile phase allows the most notable control of solute retention; this was evaluated by adding low percentages of organic modifiers of varying molecular weights to the supercritical carbon dioxide mobile phase. PGC‐SFC provides reversed phase characteristics similar to those found for PGC‐HPLC. Porous glassy carbon has selectivity characteristics previously unavailable in supercritical fluid chromatography. Use of porous glassy carbon in supercritical fluid chromatography may provide distinct advantages in difficult analytical separations, allowing separations of molecules with only slight structural differences.
Microcolumn liquid chromatography of polycyclic aromatic hydrocarbons and some isomeric compounds on cyclodextrin stationary phases
Authors: Malik Abdul , Jinno Kiyokatsu 
Published: May 2005

AbstractPreparative‐grade bonded β‐ and γ‐cyclodextrin stationary phases were used as the packing material of liquid chromato‐graphic analytical microcolumns. Although the resulting columns are characterized by relatively low efficiency, the high selectivity of the cyclodextrin phases nevertheless allows their successful use for the separation of different classes of isomeric compounds that are difficult to resolve on conventional LC stationary phases. Examples of baseline (or almost baseline) separations of a number of isomeric compounds, including isomeric polycyclic aromatic hydrocarbons, are presented to demonstrate the analytical potential of such columns. Retention behavior of the separated isomers is discussed based on the structure of the solute molecule and the possibility of its inclusion into the molecular cavity of cyclodextrin stationary phases.
The thermal immobilization of hydroxy‐terminated silicone phases in high‐temperature‐silylated glass capillaries. A study of reaction mechanisms
Authors: Welsch Thomas , Teichmann Ute 
Published: May 2005

AbstractDifferently pretreated glass capillaries were coated with hydroxy‐terminated methyl or methyl‐phenyl polysiloxane gum phases and cured at 340–360°C for several hours. The volatile reaction products formed during the baking procedure were analyzed and the retention behavior of various polar test compounds were investigated both before and after the heat treatment. The findings were used to establish a reaction scheme which explains crosslinking and surface bonding of hydroxy‐terminated silicone phases in high‐temperature‐silylated glass capillaries. The principle has been extended to the immobilization of common endcapped silicone phases by mixing them with hydroxy‐terminated phases.
Analysis of low molecular weight constituents of polypropylene and other polymeric materials using on‐line SFE‐SFC
Authors: Cotton Nicholas J. , Bartle Keith D. , Clifford Anthony A. , Ashraf Sameena , Moulder Robert , Dowle Christopher J. 
Published: May 2005

AbstractAdditives and oligomers from polymers were quantitatively extracted and separated using on‐line SFE and capillary SFC. Conditions were found which extracted the additives selectively and separated them from the co‐extracted oligomers.
Comparison of micro‐LC and capillary zone electrophoresis for the analysis of thiols
Authors: Ling B. Lin , Baeyens W. R. G. , Dewaele C. 
Published: May 2005

AbstractMicro‐LC and capillary zone electrophoresis (CZE) are two of the most rapidly developing, miniaturized separation techniques in analytical science. In the present paper, both techniques were comparatively evaluated for the determination of several important thiols derivatized with the fluorogenic reagent SBD‐F. Different parameters, such as selectivity, sensitivity, analysis time and efficiency, influence of column length, CZE buffer concentration, and voltage were thus analyzed and discussed. Both techniques are recommended for the analysis of thiols in biological samples.
Fluorescence detection with an immersed flow cell in capillary electrophoresis
Authors: Kurosu Yasuyuki , Sasaki Toru , Saito Muneo 
Published: May 2005

AbstractAn immersed flowcell has been developed for fluorescence detection in capillary electrophoresis (CE) by modifying an ordinary HPLC spectrofluorimetric detector flowcell. The minimum detectability obtained for riboflavine was about 4 fmol. The use of the flowcell to measure a fluorescence spectrum by the stopped‐flow method of shutting down the DC high voltage during a wavelength scan, has also been achieved successfully.
High performance separations of nucleic acids using capillary electrophoresis and high‐performance liquid chromatography
Authors: Baba Yoshinobu , Tsuhako Mitsutomo , Enomoto Shigeru , Chin A. Michael , Dubrow Robert S. 
Published: May 2005

AbstractHigh resolution separations of nucleic acids have been performed using high performance capillary electrophoresis (HPCE) and high performance liquid chromatography (HPLC). Electropherograms showing HPCE separations of single and double stranded DNA are presented and compared with HPLC separations. Single base resolution of poly(dA) oligonucleotides in the size range of 12 to 60‐mers was achieved in 35 min using HPCE. Plate numbers for HPCE are in the hundreds of thousands and reproducibility is about 1–2 % (RSD). In comparison with HPLC separations, the resolution of nucleic acids obtained using HPCE is much better than that using HPLC, while reproducibility of HPCE is comparable with that of HPLC.
Optimization of supercritical fluid chromatographic separation of nitroaromatics by the overlapping resolution mapping scheme
Authors: Ong Chye P. , Chin Kiat P. , Lee Hian K. , Li Sam F. Y. 
Published: May 2005

AbstractThe use of an interpretative optimization method to predict optimum conditions for the supercritical fluid chromatographic separation of nitroaromatics is demonstrated. The scheme utilizes the overlapping resolution mapping (ORM) procedure for multivariate prediction of the pressure gradient and temperature in order to separate eight nitroaromatics. Using the ORM scheme, only seven experiments were conducted before a global optimum was revealed. All the peaks were satisfactorily separated using experimental conditions derived from the scheme.
Preparation and evaluation of phenylpropyl‐treated porous glasses for high performance liquid chromatography
Authors: Okamoto Mitsuyoshi , Nobuhara Kazunori , Jinno Kiyokatsu 
Published: May 2005

AbstractThe retention and selectivity behavior of some aromatic hydrocarbons and alkylbenzenes on phenyl‐ or phenylpropyl‐modified glasses have been studied by high performance liquid chromatography. From elemental analysis data for carbon, the maximum number of accessible phenyl or phenylpropyl surface groups per 100 Å2 of glass (mean pore diameter, 157 Å; specific surface area, 213 m2/g) in the phenyl and phenylpropyl modified glasses were calculated to be 1.93 and 1.97, respectively. Using 60:40 methanol‐water mixtures as eluents, the aromatic hydrocarbons or alkylbenzenes were separated on the glasses studied, but with different degrees of resolution.
Optimization of a high speed countercurrent chromatograph for analytical separations
Authors: Oka Hisao , Ikai Yoshitomo , Kawamura Norihisa , Yamada Masuo , Hayakawa Junko , Harada Ken‐Ichi , Nagase Kazuko , Murata Hideaki , Suzuki Makoto , Ito Yoichiro 
Published: May 2005

AbstractThe analytical capability of the high speed countercurrent chromatograph model 4000 (HSCCC‐4000) has been improved by optimizing the dimensions of the multilayer coiled column. Using a two‐phase solvent system of n‐hexane – ethyl acetate – methanol – water (1:1:1:1) and a set of indole auxins as test samples, a series of studies was conducted to evaluate performance of coiled columns with i.d.s ranging from 0.1 to 0.55 mm. The studies on the stationary phase retention indicated that multilayer coils of 0.55 mm and 0.30 mm i.d. provide satisfactory retention of the stationary phase while the 0.10 mm i.d. column fails to yield reproducible retention. The best partition efficiencies were obtained from the 0.30 mm i.d. multilayer coil with a 6 ml capacity which produced theoretical plate numbers ranging from 5500 to 10500 with a resolution factor of 2.30. The feasibility of interfacing the HSCCC‐4000 with a mass spectrometer is briefly discussed.
Unusual peak defocusing in capillary GC on hexakis(2,6‐diO‐pentyl‐3‐O‐acetyl)‐α‐cyclodextrin stationary phase
Authors: Schmarr Hans‐Georg , Maas Birgit , Mosandl Armin , Bihler Stephan , Neukom Hans‐Peter , Grob Konrad 
Published: May 2005

AbstractAn unusual peak defocusing effect influencing chromatographic performance over a limited range of elution temperatures is described for hexakis(2,6‐di‐O‐pentyl‐3‐O‐acetyl)‐α‐cyclodextrin stationary phase. Since this phenomenon is likely to be dependent on minor details of the cyclodextrin molecule, full assignment of the 1H‐ and 13C‐NMR‐spectra are given.
Capillary gas chromatography of lower aliphatic C2C5 aldehydes in the free form as a group of pungent odorants in air
Authors: Hoshika Yasuyuki , Muto Giichi 
Published: May 2005

AbstractThe capillary gas chromatography of the C2‐C5 lower aliphatic aldehydes (e.g.,acetaldehyde, propionaldehyde, n‐ and i‐butyraldehydes, n‐ and i‐valeraldehydes) which, in the free form in air, have unpleasant odors and low threshold odor values, has been studied using cold‐trap preconcentration with liquid oxygen. The capillary column outlet was connected to enable simultaneous detection by FID, ECD, FPD AND FTD (SID).