bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies of open tubular micro capillary liquid chromatography. 1. The development of open tubular micro capillary liquid chromatography
Authors: Hibi K. , Ishii D. , Fujishima I. , Takeuchi T. , Nakanishi T. 
Published: May 2005

AbstractMicro capillary columns were successfully applied to liquid chromatography by employing the principles used in micro high performance liquid chromatography. Fundamental investigations on the use of capillary columns in LC were performed for the various column parameters. Good separations of five aromatic hydrocarbons and four kinds of phthalic esters were obtained on a 62 μm I.D. capillary column, coated with SE‐30.
Computer reconstruction of high resolution gas chromatograms
Authors: Overton E. B. , Steele C. F. , Laseter J. L. 
Published: May 2005

AbstractThis paper describes two programs that are used to plot digital area slice data from glass capillary gas chromatograms. The programs are written in H/P LAB BASIC II, and can be executed on Hewlett‐Packard 3354A Laboratory Data Systems using digital plotting devices. The programs are designed to plot high resolution chromatograms, allow horizontal and vertical scaling, and the plots can be numbered and labelled.
Separation of 28 to 114°C hydrocarbons with glass capillary columns
Authors: Mathews R. G. , Torres J. , Schwartz R. D. 
Published: May 2005

AbstractTechniques have been developed for the rapid separation (about 20 minutes) of the 39 compounds in crude petroleums, or petroleum distillates, which boil between 28 and 114°C. A 300 meter glass column (0.25 mm i.d.) which is etched, coated with a mixture of normal hexadecane and Kel‐F10157 is utilized to perform this separation at room temperature. The separations obtained with this non–polar liquid mixture and the «inert» glass surface are much more rapid than those previously obtained with stainless steel capillary columns.
Studies of correlation between chemical structure and Rf‐value in high performance TLC
Authors: Bidló‐Iglóy Margit 
Published: May 2005

AbstractCorrelation between chemical structure and Rf‐values was studied in the case of aniline and its derivatives using high performance TLC and a U‐chamber. The characteristic group constants referring to each substituent were determined by chromatographing derivatives with one substituent and aniline in toluene and dibutyl ether respectively. On the basis of these constants the RM and Rf values of derivatives with more substituents were calculated. Comparing the calculated and measured values good agreement was found.
Anticircular high performance thin‐layer chromatography
Authors: Kaiser R. E. 
Published: May 2005

AbstractThe principal analytical details for the third of three possible modes in high performance thin‐layer chromatography are given, namely the anticircular mode. Separation is achieved by allowing the mobile phase to enter the plate layer on a precise outer circle line, from where it flows towards the centre with nearly constant speed. This technique is theoretically and practically the fastest of all three possible in HPTLC. It permits maximum sample capacity with a minimum of time, layer and mobile phase consumption. It is therefore the most economical HPTLC technique.A new carrier‐free mobile phase transfer principle is used. The conditions for qualitative and quantitative analysis are good: repeatability, reproducibility and accuracy of routine TLC analyses are superior to those achieved by the classical trough technique. The specially narrow spot‐path in anticircular HPTLC facilitates automated quantitation. Compared with the linear and circular modes, the anticircular mode shows better separation and significantly increased sensitivity at higher Rf‐values. The drawback, however, is that the separation power (expressed by the separation number) is lower compared with the other two modes.
Methods in high resolution gas chromatography. Two‐dimensional techniques
Authors: Bertsch W. 
Published: May 2005

AbstractBasic methodology to effect the separation of complex samples by gas chromatography is discussed from an experimental point of view. Several possibilities are presented which are commonly used to enhance the information content of a gas chromatographic run. These include incorporation of more than one set of retention data, multiple detectors, and special column switching techniques. These and other techniques have sometimes been labeled “multidimensional” in the literature. An attempt is made to define the term “two‐dimensional chromatography”.The review is divided into sections which point out the different directions which have been taken to deconvolute chromatographically unresolved components. Particular emphasis is placed on technology which is capable of dealing with samples of extreme complexity, and instrumentation for trace‐ and ultratrace analysis is dicussed with specific examples. The future of two‐dimensional techniques in gas chromatography is looked into.
HPLC of antibiotics. 1. Streptolydigin and related compounds
Authors: Brodasky Thomas F. 
Published: May 2005

AbstractTwo new acyltetramic acids related to streptolydigin have been isolated from fermentations of Streptomyces lydicus. The principal members of this complex were resolved by TLC on silica gel. However, the methods of detection, permanganate spray or bioautography, were not suitable for both crude fermentation broths and purified extracts. Gas chromatography is unsuitable for the detection of either underivatized or silylated streptolydigins. High performance liquid chromatography (HPLC) particularly on triethylaminoethyl cellulose is rapid and sensitive and is the method of choice for the analysis of both crude and purified samples. Using high performance liquid chromatography, two components were detected in the complex, which are not observed using any of the other chromatographic procedures.
Systematic and statistical errors in quantitative evaluation using TLC and HPTLC. 2. Internal and external standard methods
Authors: Ebel S. , Glaser E. , Rost D. 
Published: May 2005

AbstractThe error propagation is given for routine analysis by in situ evaluation in TLC using the methods with internal or external standard. The internal standard method will need four different measurements of peak height or area, while the external standard method uses only two measurements. Therefore in the latter case the error of the spotting volume will cause errors in the determined concentration. By error propagation it can be shown, that the internal standard method gives better results, if the error in measuring peak height or area is less than the error of the spotting volume.
On‐column injection onto capillary columns. Part 2: Study of sampling conditions; practical recommendations
Authors: Grob K. 
Published: May 2005

AbstractDuring one year continuous use of on‐column injection, the typical advantages described in our first report have fully been confirmed. In addition the analysis of large sample volumes has proved promising. Only minor modifications have been applied to the on‐column injector device. Broad evidence has been gathered showing that full separation efficiency of the capillary columns after on‐column injection is attained only when cold trapping or the solvent effect, as band shortening mechanisms, are working‐ While, under the conditions of on‐column injection, cold trapping is less efficient than with other injection techniques, the opposite holds true for the solvent effect. Compared with splitless injection, the danger of excessive solvent condensation on the column is increased. A working rule is presented for establishing the optimal chromatographic conditions for handling large sample volumes while ensuring full separation efficiency yet avoiding harm to the column.
The influence of the syringe needle on the precision and accuracy of vaporizing GC injections
Authors: Grob K. , Neukom H. P. 
Published: May 2005

AbstractThe discrimination of the high boiling components of a C9 to C44 alkane test mixture in a vaporizing injector (analysed with stream splitting on a capillary column) is mainly due to a selective elution of the sample out of the syringe needle. Different methods of handling the syringe needle are tested. The discrimination is quantitated and correlated with the material left in the needle. The poorest method of injection was found to retain the sample in the needle when the latter is introduced into the vaporizer. The sample should be pulled back into the barrel of the syringe and the needle allowed to warm up in the injector before the sample is transferred into it. The solvent flush technique may be preferred for components sensitive to the hot metal surface of the needle.
Efficiency of composite vs. conically shaped chromatographic columns
Authors: Said A. S. 
Published: May 2005

AbstractThe theory of composite chromatographic columns has been re‐examined and general equations relating their efficiency to those of individual columns were derived. The derivations were based on elementary principles without reference to the principle of variance additivity. Derived also, were general equations for the efficiency of columns with continuously varying diameters, HETP and other properties from which formulae for special cases of practical interest were deduced. An example comparing the efficiencies of two columns, one conical and the other composite was given. The calculations show clearly that the conical column is superior in efficiency for the same total length and total retention volume.
Computer reconstructed gas and liquid chromatograms
Authors: Janssens G. 
Published: May 2005

AbstractThis paper describes a Lab Basic II program which allows the reconstruction of GLC‐chromatograms on a Hewlett‐Packard 2648A graphics terminal, starting from raw data gathered by the HP‐3354A Laboratory Data System. The introduction of a considerable number of automatic parameter selections restricts user's interventions. The program can be run in terminal mode or be recalled as a post‐analysis program when working in autocall mode.
A new approach to the simultaneous multi‐detection technique with electron capture and flame ionization in series
Authors: Poy F. 
Published: May 2005

AbstractIn order to avoid splitting at the column outlet for simultaneous multidetection, a new line of detector heads with the ionization cells coupled in series has been developed.The electron capture plus flame ionization detector (EC+FI‐D) has been evaluated from the point of view of the sensitivity, the linear dynamic range and separation efficiency in a capillary column GC system. The performances of each section are the same as when a single ionization detector head is used.
Gas‐liquid chromatography of serum bile acids using glass capillary columns
Authors: Karlaganis G. , Paumgartner G. , Schwarzenbach R. P. 
Published: May 2005

AbstractThe proposed combination of a rather simple procedure for sample preparation with capillary gas‐liquid chromatography using a barium carbonate/polyethyleneglycol 20,000 column and a Grob‐type on‐column injector permits measurement of bile acids in serum with high separation efficiency, short analysis time and complete separation of bile acids from cholesterol. The method can be adapted to combined capillary gas‐liquid chromatography ‐ mass spectrometry.
Precision of an automated all‐glass capillary gas chromatography system with an electron capture detector for the trace analysis of estrogens
Authors: Kern H. , Brander B. 
Published: May 2005

AbstractSubnanogram detection of steroids has become increasingly important today. One applicable method for gas chromatographic determination of subnanogram quantities of estrogens as halogenated derivatives is electron capture detection. HFB‐derivatives of 7 different estrogens were automatically injected onto a prolonged narrow bore wall‐coated glass capillary column. Normal split injection could not be used for this trace analysis because of too much loss of sample. Only small amounts of sample were available from which double analysis had to be performed.Cross‐contamination of the automatic sampling system as well as precision of retention times and peak areas were determined.The type of injection described showed better quantitative results compared to the splitless injection technique.All details of the system used together with the results are this discussed in this paper.
Faster GC analyses performed by flow programming in short capillary columns
Authors: Nygren S. 
Published: May 2005

AbstractThe technique of programming the carrier gas flow rate in gas chromatography, especially in connection with the use of capillary columns shorter than 10 m can significantly accelerate GC analyses. Equations for calculation of the parameters of the exponential flow function and retention data are described. The effects of flow programming in a short capillary column are shown in a few chromatograms. Different programming rates are tested and compared with temperature programming.
High‐temperature (GC)2/MS investigations
Authors: Dielmann G. , Meier S. , Rapp U. 
Published: May 2005

AbstractThe analysis of low volatile compounds by (GC)2/MS using high‐temperature stable glass‐capillary columns and a commercially available GC/quadrupole MS instrument is described.It will be shown that no special modifications or procedures are required in analyzing organic compounds exceeding carbon numbers of 50. The application to industrially and naturally occuring high boiling mixtures will be discussed.
An investigation of glasses for capillary chromatography
Authors: Dandeneau Raymond D. , Zerenner E. H. 
Published: May 2005

AbstractAn investigation was conducted of various glasses, other than soda lime or borosilicate, for use in glass capillary gas chromatography. The work has uncovered some unique chromatographic qualities in the use of potash soda lead and fused silica glasses as materials for making glass capillary columns. The fused silica proved to be an ideal material for capillary column construction, being inherently more inert than glass containing metal oxides. It has been shown that through the use of thin wall capillary tubing of high flexibility many of the mechanical problems associated with glass capillary columns, such as fragility and column straightening, can be avoided.
Identification and quantitation of trace amounts of barbiturates with glass capillary gas chromatography
Authors: Dünges W. , Langlais R. , Schlenkermann R. 
Published: May 2005

AbstractPre‐chromatographic reactions are no longer a necessary evil. Equipment such as the microrefluxer now allows reproducible 7‐μl‐reactions to be carried out in a short time. Thus multiple derivatisations can be used together with glass capillary GC for routine identifications. The method has been succesfully applied to barbiturates. Retention data of their methyl‐, allyl‐ and benzyl‐derivatives are given.Quantitative blood level determinations are briefly discussed.
Study of open‐tubular micro‐capillary liquid chromatography
Authors: Ishii D. , Tsuda T. , Hibi K. , Takeuchi T. , Nakanishi T. 
Published: May 2005

AbstractCapillary columns in gas chromatography, first proposed by Golay [1,2], have become well established [3] which have extremely high column efficiencies and separabilities. Everyone could imagine it to be a great tool if such a kind of high efficiency column could be established in liquid chromatography (LC). Microcapillary liquid chromatography (MCLC) may be one way of achieving high‐efficiency in terms of theoretical plates. Few papers were published in this field before 1976 [4–6], but more recently, after 1977 [7–15], this field has become one of topical interest in liquid chromatography. Temporarily there are two microcapillary liquid chromatography, that is: „open‐tubular”︁ [7,8,10–15] and „packed”︁ [9] MCLC. In this presentation we focus on open‐tubular microcapillary liquid chromatography and a review contemporary developments of ours and others.
The use of glass capillary columns for the analysis of polar natural products
Authors: König W. A. , Günther W. 
Published: May 2005

AbstractTwo published procedures for glass capillary column production are applied to produce capillaries for chromatography of polar natural compounds. Soda lime glass capillaries, after leaching with aqueous HCL, are either treated with colloidal silicic acid or with barium carbonate and coated with either Silar 7CP or SE 52. A test mixture as well as polar carbohydrate and peptide mixtures are chromatographed on the different columns and their chromatographic properties are evaluated. Combined capillary gas chromatography‐electron impact and chemical ionization mass spectrometry are used for identification of the peptide sequence.
Gas chromatographic conditions for the linearity of the relationship between σT,t and tR in open tubes
Authors: Smuts T. W. , Buys T. S. , de Clerk K. , du Toit T. G. 
Published: May 2005

AbstractThe linearity of the relationship between σT,t2 and (1 + k)2 is studied with the view of using it for the evaluation of GC equipment. Based on appropriate analytical expressions it is concluded that in general this relationship is not linear and that practical procedures for column evaluation should be developed that take this non‐linearity into account.
Chromatographic peak broadening with a lab‐made splitter: Reproducibility and accuracy studies
Authors: Watanabe Chuichi , Tomita Hiroshi , Sato Kunitaka 
Published: May 2005

AbstractSample inlet splitters are used in capillary column gas chromatography. We have investigated the sample band broadening in the splitter and studied reproducibility and accuracy in quantitative analysis using a simple lab‐made splitter. It was found that the results were dependent upon the operating conditions such as split ratio, splitter temperature, glass wool plug, injected sample volume and solvent.
On the estimation of extra‐column contributions to band broadening through measurements on an authentic chromatogram
Authors: Nilsson O. 
Published: May 2005

AbstractThe time constant, τ, is determined from the tail of an authentic HPLC peak through a plot of In U versus time, t, according to the relation

expected at low recorder deflexions, U. The value obtained, τ = 2.43 s, is one order of magnitude larger than an ordinary recorder time constant, which is quite normal for LC detectors. It agrees with the value, τ = 2.44 s, needed theoretically to distort a Gaussian‐shaped peak so as to obtain the experiment‐ally found second moment, σ2 = 11.13 s,2 and the experimental difference between first moment t and peak retention time tmax, t – tmax = 0.78 s. The determination is therefore regarded as a demonstration of the variance addition rule

where σ is the second moment of the non‐distorted peak. The column contribution version

is also considered. This equation was appliied earlier to an estimation of extra‐column contributions to band broadening with the aid of the “abt” concept. An explicitly k‐(capacity ratio)‐dependent expression for the mass exchange contribution, σ is derived from Golay's equation for capillary columns, but the validity of the Golay equation is under discussion.
Ion pairing high‐performance liquid chromatography of catecholamines
Authors: Heady Judith E. , Agee Karl D. 
Published: May 2005

AbstractCatecholamine standards have been separated by ion pairing reversed‐phase high‐performance liquid chromatography (HPLC). A trace substance was separable from four standards when low concentrations of methanol were used in the elution buffer. This method has allowed separation of an unknown uterine catecholamine, partially purified on a boronate affinity gel column, from the standards: norepinephrine, epinephrine, normetanephrine and metanephrine.
On the applicability of the “abt” concept
Authors: Nilsson O. 
Published: May 2005

AbstractKaiser's “abt” concept rests on the experimental establishment of a linear relation between band width at half height, b0.5, and capacity ratio, k, according to

His column specification quantity, hreal, is dependent on the square of the slope a, obtained from a linear regression analysis based on this relation. It is shown in the present paper that an improvement of the experimental conditions leading to a lower extra‐column contribution to band broadening, b, introduces a tendency towards a negative curvature in the plot at low k values. The mean slope increases, and an uncritical linear regression would yield an hreal‐value which is higher than before and which would be in the opposite direction to the requirements of a reliable column specification. Generally the linear regression analysis has to be moved to higher k regions in cases of curvature, especially as it is also shown that hreal is an estimation of the traditional HETP value, H∞, that would be obtained when k approaches infinity. This theoretically expected relation

is a strong motivation for the use of hreal as a column specification, since the b0.5‐value associated with H∞ is expected to be practically independent of b.
Simple conversion of two standard gas chromatographs to all‐glass capillary systems
Authors: Severson R. F. , Arrendale R. F. , Chortyk O. T. 
Published: May 2005

AbstractTwo regular GC instruments were modified with injection port liners, split‐mode injection systems, pressure regulators, effluent traps and needle valves to produce an all‐glass GC‐2 system. This simple and inexpensive system allows the quantitative analyses of phenols, hydrocarbons, acids, sterols, terpenoids, and alkaloids with excellent reproducibility and linear response. Even more impressive was its ability to analyze a C45‐terpenoid alcohol, solanesol, as its TMS‐derivative (M.W. 702).
Effects of solute‐solvent and solvent‐solvent association in liquid adsorption chromatography with binary mobile phase
Authors: Jaroniec M. , Piotrowska J. 
Published: May 2005

AbstractAnalytical equations for the capacity ratio in liquid adsorption chromatography with a binary mobile phase, involving solute‐solvent and solvent‐solvent association in the mobile and surface phases, have been derived. Very simple equations have been obtained for higher values of mole fraction of the more efficient eluting solvent.
High efficiency HPLC with long packed columns
Authors: Dewaele C. , Verzele M. 
Published: May 2005

AbstractCoupling several 25 cm × 2 mm ID analytical columns together is a simple and easy way to achieve high resolution HPLC (20,000–50,000 plates). How to do this with commercially available instruments, injectors and detectors is described in the paper.An attractive feature of the long narrow column approach is that the same HPLC set‐up can be used for both fast‐low and slow‐high efficiency separations.High efficiency is essential for really complex natural mixtures, e.g. the hop and beer bitter acids. Some examples are shown.
Stability of the FID sensitivity during an analysis in capillary GC
Authors: Grob K. 
Published: May 2005

AbstractThe sensitivity of an FID may change when the carrier gas flow rate changes during a chromatographic run. Sample parts which are eluted at reduced FID sensitivity produce a reduced peak area, hence are discriminated as compared to other components. Sensitivity changes were studied for hydrogen as carrier gas. For the detector tested, differences in the carrier gas flow rates of 1 ml/min shifted the FID sensitivity by 1 to 5% (depending on the fuel gas supply). Thus the stability of the sensitivity is no longer ensured as soon as the carrier gas flow rate is changed manually or by an automatic programmer during an analysis. Sensitivity drifts may also occur during temperature programmed runs with a pressure regulated carrier gas supply since the gas flow through the capillary drops with increasing temperature. Such shifts in the response became noticeable as soon as relatively high carrier gas flow rates combined with long range temperature programmes were used. The typical patterns of such discriminations are shown, closing with a discussion on the possibilities for minimizing such undesired effects.