摘要:

A comprehensive analysis of interactive polymer chromatography is presented. Isocratic liquid chromatography of polymers at the critical eluent composition (the transition point where size-exclusion and adsorption interactions completely compensate each other) is currently used to separate functional oligomers and block copolymers. We have extended the concept of this critical elution chromatography to the cases of statistical copolymers as well as porous stationary phases with heterogeneous surfaces (viz., surfaces with both inert and active groups). The theory provides the quantitative condition for statistical copolymer chains to have a single adsorption-desorption transition point. The random copolymers with narrow chemical composition distribution (CCD) always posses such a point. For non-random copolymers this condition includes the comparison between the mean length of chain segments connecting the attractive walls of the pore and the chemical correlation segment characterizing the randomness of the copolymer microstructure or the surface of this pore.

ISSN:1082-6076    

DOI:10.1081/JLC-100102075

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The molecular-statistical theory of polymer solutions in confined media is applied to the conventional chromatographic theory of gradient elution. This approach leads to the prediction of the special mode of interactive polymer chromatography: gradient elution at critical point of adsorption. We demonstrate theoretically and experimentally that under appropriate conditions elution of each compositionally homogeneous fraction of copolymer occurs at the critical mobile phase composition.

ISSN:1082-6076    

DOI:10.1081/JLC-100102076

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The enantioselectivity of the amylose tris(3,5-dimethoxyphenyl carbamate) phase towards some β-blockers was investigated. A sensitive HPLC method was developed for the enantiomers of metoprolol and betaxolol. The validated methods were suitable for the analysis of enantiomeric composition in a variety of pharmaceutical formulations of both drugs.

ISSN:1082-6076    

DOI:10.1081/JLC-100102077

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

ViscumL. is a semi-parasitic genus growing on various host plants, such as trees and shrubs. The plant is known as “Ökse Otu” in Turkey. In our country,ViscumL. is represented by one species and 3 subspecies. These subspecies areV.albumssp.album,V.albumssp.abietis,V.albumssp.austriacum. Comparative investigations were carried on with the active principles, phenylpropanoid glycosides, of the subspecies ofV.album.

ISSN:1082-6076    

DOI:10.1081/JLC-100102078

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

It is shown that an initial scan of a mixture with a gradient elution programme offers a rapid and easy procedure for predicting the isocratic conditions. The experimental design methodology facilitates optimisation of the chromatographic separation of vitamin molecules dependent on the determination of mathematical equations. The specialised cubic equations have been elaborated. Examples are shown of chromatographic separations obtained using mobile phase combinations which were the best compromise of the two selected criteria.

ISSN:1082-6076    

DOI:10.1081/JLC-100102079

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

ISSN:1082-6076    

DOI:10.1081/JLC-100102080

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The separation of mixtures of avidin, streptavidin, and neutravidin were investigated by using combinations of C8phase capillary and some surfactants such as anionic, cationic, zwitterionic, nonionic surfactants, polyvinyl alcohol (PVA), and hydroxyl cellulose (HEC) polymers. The combination of zwittergent 3 – 14 and C8phase capillary gave the best separation of avidin and its relatives. The satisfactory reproducibility of the peak height and the migration time were achieved by this system. The complete separation of the mixture of avidin, streptavidin, neutravidin, and other three basic proteins was achieved with sharp peaks in pH 5, 7 and 9 of running buffers.

ISSN:1082-6076    

DOI:10.1081/JLC-100102081

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A rapid bioanalytical method has been developed for the determination of pemoline in urine, using 4-methyl-primidone as the internal standard. The analyte was isolated from urine with a C18reverse solid-phase extraction column and analysed by high performance liquid chromatography with a photo diode array detector. The method was linear in the studied range of 0.20 to 1.40 μg/ml urine. For the standard curve a weighted (1/x2) linear regression line (y = - 0.006 + 0.976x) was computed and validated (R2= 0.998). The limit of quantitation was 0.04 μg/ml urine. Recovery studies for the accuracy gave a mean percent recovery of 93.9 and a predicted percent recovery in the range of 91.5 to 96.0. The precision, expressed as coefficient of variation, was in the range of 2.03 to 3.67 μg/ml for the intraday and from 1.96 to 4.35 μg/ml for the inter-day. The ANOVA (analysis of variance) tables were also given to validate the day to day reproducibility. Application of the method to clinical samples was demonstrated.

ISSN:1082-6076    

DOI:10.1081/JLC-100102082

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A new procedure to reduce the background noise of multichannel chromatographic data, named SPEAK, has been developed. It is based on the assumption of gaussian elution profiles, but it can also deal with non-gaussian peaks.

ISSN:1082-6076    

DOI:10.1081/JLC-100102083

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor