摘要:

A modified polyamidoamine-starburst dendrimer (PAMAM-SBD), 16-cascade:(1,4-diaminobutane)[4-1,4]:(1,6-diaza-7-oxo-nonyl idene)2:propanoic acid methyl ester (DABD), was synthesized and used as a carrier in electrokinetic capillary chromatography. The utility of DABD is demonstrated with the separation of a mixture of naphthalene derivatives and five neutral aromatic molecules without the need for an organic solvent as a modifier. Separation of a mixture of five neutral aromatic molecules were optimized through dendrimer concentration, pH, and organic modifier. The modified polyamidoamine-starburst dendrimer offered selectivity for polynuclear aromatic hydrocarbons as well as naphthalene based derivatives. However, DABD did not provide as much selectivity for neutral aromatic compounds in the presence of organic modifier.

ISSN:1082-6076    

DOI:10.1080/10826079808005845

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Under each of 38 buffer conditions, six migration parameters of 14 flavonoids were obtained in capillary zone electrophoresis (CZE) and nine parameters in micellar electrokinetic capillary chromatography (MEKC). A total of 183 structural descriptors for each flavonoid were calculated to represent the molecular structures in a quantitative way. The relationship between the structural descriptors and the migration parameters of flavonoids in CZE or MEKC were evaluated by cluster and factor analyses.

ISSN:1082-6076    

DOI:10.1080/10826079808005846

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

ABSTRACT

ISSN:1082-6076    

DOI:10.1080/10826079808005847

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

An analytical method utilizing the HPLC-SEC fingerprints of crude oils derived from UV-DAD and IR detectors is presented. It can determine rapidly and accurately the contribution of different crude oils in pipeline mixtures and in commingled production streams.

ISSN:1082-6076    

DOI:10.1080/10826079808005848

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A simple and sensitive liquid chromatographic method is described for the simultaneous determination of docosanoic, tetracosanoic and hexacosanoic acids as fluorogenic derivatives. These acids, spiked in plasma, were extracted with n-heptane and the resulting extract was derivatized with 4-bromomethyl-7-methoxycoumarin (BrMmC) in dichloromethane using potassium carbonate and 18-crown-6 as catalysts. The derivatives obtained were chromatographed on a reversed-phase C8column with acetonitrile: water (91: 9, v/v) as a mobile phase and 7-methoxy-4-(tricosanoyloxymethyl)-coumarin as an internal standard. The linear ranges for the determination of docosanoic, tetracosanoic, and hexacosanoic acids were over 31-500, 36-580 and 36-580 pmol, respectively. The limit of detection for each acid was about 0.3 pmol per 10 μL injection (S/N=3).

ISSN:1082-6076    

DOI:10.1080/10826079808005849

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A high performance liquid chromatographic assay was developed and validated for a simultaneous determination of adriamycin and its metabolites adriamycinol and adriamycinone as well as daunomycin in plasma. Acetonitrile and trichloroacetic acid were employed in removing proteins and extracting the drugs and metabolites into the supernatant for HPLC. Enhancement of chemical stability of the anthracyclines during sampling procedure was investigated using 0.01 M γ-cyclodextrin. The processed samples were chromatographed using an ODS/TM column (150 × 4.6 mm I.D.) eluted with a mobile phase composed of 35% acetonitrile and 65% (0.1M) monobasic phosphate, containing 0.3% heptafluorobutyric acid, pH 3.

ISSN:1082-6076    

DOI:10.1080/10826079808005850

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Chromatographic behavior of metal complexes with 8-hydroxyquinoline, 5-chloro-8-hydroxyquinoline, and 5,7-chloro-8-hydroxyquinoline in the reversed-phase system has been studied using a variety of organic modifiers. In the acetone modifier system, the capacity factors (k') of the corresponding vanadium(V), nickel(II), and cobalt(III) complexes increased with increasing number of substituted chlorine atoms in the ligands. With acetonitrile-water as the mobile phase, the k' values of the metal 8-hydroxyquinoline complexes decreased with increasing contents of the modifier, depending on the strength of polarity parameters. The k' values, experimentally determined, can be related to the polarity parameters of organic modifiers for tervalent metal ions, but not for monovalent and divalent ions.

ISSN:1082-6076    

DOI:10.1080/10826079808005851

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A novel method for the determination of benzoyl peroxide bleach in wheat flour by using high performance anion exchange chromatography (HPIC) after decomposition to benzoic acid was proposed. Benzoyl peroxide was effectively extracted from wheat flour with absolute ethanol by ultrasonication under neutral condition and converted to benzoic acid in the presence of potassium hydroxide solution. The chromatographic separation of benzoic acid was performed on a Dionex OmniPac PAX-100 separation column and the determination by ultraviolet absorbance detection at 222 nm. Good linearity between the concentration of benzoyl peroxide and peak area response was achieved in the range of 0.12−20 μg/mL. The detection limit (signal-to-noise ratio 3:1) was 19 ng/mL for benzoyl peroxide. The method has been successfully applied for the analysis of real samples, and the average recoveries for various samples ranged from 81 to 92%.

ISSN:1082-6076    

DOI:10.1080/10826079808005852

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A simple, rapid, and sensitive method for determining 10 arylamine compounds in wastewater sample using solid-phase extraction (SPE) and high performance liquid chromatography (HPLC) with UV detection is developed. An SPE procedure is described for extracting and preconcentrating the arylamines on Sep-Pak C18 cartridges with methanol as solvent. A mobile phase gradient of acetonitrile-water was used for the separation and determination of the arylamines.

ISSN:1082-6076    

DOI:10.1080/10826079808005853

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A method based on the combined use of off-column solid phase extraction (SPE) using C18membrane disk and on-column field amplified injection (FAI) was developed to isolate, recover, and concentrate nitrophenols in river water prior to analysis by capillary electrophoresis (CE). The effect of eluent, sample pH, and volume in SPE, sample solvent and injection volume in FAI, and the combination of SPE and FAI was investigated in order to find optimal conditions for overall enrichment. With the use of SPE combined with FAI, extraction time was reduced, most interferences were removed, limit of detection was decreased to 5−10 ppb, and recovery of each nitrophenol was > 80%. Combination of off-column SPE and on-column FAI provides a rapid and selective approach for quantitatively concentrating nitrophenols in river water at ppb level prior to CE analysis.

ISSN:1082-6076    

DOI:10.1080/10826079808005854

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor