摘要:

A capillary electrophoresis method has been developed for the analysis of melatonin, which depends on whether tryptamine and serotonin must be determined as well. If only a melatonin analysis is required, a bare capillary with a pH 4.41 buffer separates the analyte from the other two compounds, which are unresolved. If determination of all three species is necessary, a bare capillary with a pH 2.14 buffer is used. For better resolution of tryptamine and serotonin without the analysis of melatonin, a chemically modified capillary surface that lowers the electroosmotic flow is necessary.

ISSN:1082-6076    

DOI:10.1080/10826079808006876

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Fully sulfonated sodium poly(p-styrenesulfonate) (designated as NaPpSS) was prepared from sodium p-styrenesulfonate monomer and the elution characteristics of NaPpSS and commercially available poly(styrenesulfonate) which was prepared by direct sulfonation of polystyrene (designated as NaPSS) were compared using columns packed with glycerylpropyl group-bonded silica gel and poly(styrene sulfonate) gel by changing ionic strengths of the mobile phase. Plots of log [η]M and retention volumes for NaPpSS, NaPSS and pullulan showed that the retention volumes of NaPpSS and NaPSS increased with increasing the ionic strength of the mobile phase, but the extent of changing retention volume was different between these two types of compounds. Early elution of NaPpSS and NaPSS relative to pullulan of the same molecular size is governed by the ion-exclusion effect and NaPpSS eluted earlier than NaPSS of the same molecular size.

ISSN:1082-6076    

DOI:10.1080/10826079808006877

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The size of intracellular 2′-deoxythymidine-5′-triphosphate (dTTP) pools is an important indicator of cytotoxicity in cells exposed to antiviral drugs and mutagens.

ISSN:1082-6076    

DOI:10.1080/10826079808006878

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Resolution can be enhanced and separation time shortened in the capillary zone electrophoresis (CZE) separation of complex mixtures of acidic analytes that differ in pKavalues but have similar electrophoretic mobilities through an electroosmotic flow (EOF) gradient. The EOF gradient is created by a dynamic dilution of Mg2+in the inlet reservoir, which is in the buffer as an EOF modifier, as the electrophoresis proceeds. Initially, the Mg2+buffer enters the capillary by electromigration and produces a low EOF compared to the absence of Mg2+. As the Mg2+in the buffer in the inlet reservoir is diluted dynamically the EOF from the inlet side increases dynamically. Migration times for the fast-moving analytes are increased at a high Mg2+buffer concentration in the initial stages of the separation while the migration times for the slow-moving analytes are shortened by the EOF increase generated as Mg2+is diluted during the gradient. The dynamic gradient, where EOF starts low and increases, influences analyte migration time, resolution, and separation time. The effect of initial Mg2+buffer concentration, the rate of Mg2+dilution, and the time delay in generating the gradient are parameters that can be altered to influence the CZE gradient separation. Several model analyte mixtures are used to illustrate the scope of the EOF gradient conditions.

ISSN:1082-6076    

DOI:10.1080/10826079808006879

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

An unexpected chromatographic behavior of fat globules has led to a simple HPLC assay for glycerin in the complex matrix of fat emulsions intended for intravenous injection. When a combination of a Hamilton PRP-1 (Polymer Reverse-phase) Column, a Biorad Microguard Carbo C Guard Column, and a Biorad HPLC Carbohydrate Analysis Column connected in series in the order listed was used for the separation of glycerin, with water as the mobile phase, the fat globules eluted unretained. The glycerin, which eluted by aqueous size exclusion, was detected and quantitated using a refractive index detector.

ISSN:1082-6076    

DOI:10.1080/10826079808006880

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Safflower oil and soybean oil, which are the major constituents of fat emulsions for intravenous use, are both complex mixtures of triglycerides. Separation of triglycerides from the other ingredients of IV fat emulsion and their elution together as a single peak have been achieved through the use of a highly retentive Polymer Reverse Phase (PRP) column in tandem with a strong mobile phase. Quantitation is performed against a standard preparation of soybean oil using refractive index detection. The procedure is based on the use of the composite response from a known amount of one complex mixture of triglycerides to quantitate another complex mixture of triglycerides, which may even differ from the former in composition. A validation strategy for this unique situation has been developed and implemented.

ISSN:1082-6076    

DOI:10.1080/10826079808006881

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A quercitrin rich vegetal flavonoid sample was fractionated using a new hydrodynamic CCC apparatus based on the Ito scheme IV design. The Kromaton CCC apparatus has two spools with a tube coiling allowing work with two different apparatus volumes. The small “analytical” volume was 94 mL and the large “preparative” volume was 1.07 L. The fractionation of the flavonoid sample was done using the two machine volumes. The bi phasic liquid system was a non chlorinated solvent system, butanone/water. UV detection was possible at 330 nm. In one run, 330 mg of the flavonoid sample could be fractionated by the CCC machine in six peaks that were collected in nine fractions.

ISSN:1082-6076    

DOI:10.1080/10826079808006882

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The preparation of amylopection tris(phenylcarbamate) (ATP) chiral stationary phases(CSPs) coated on a small-particle (5μm, 120Å) spherical silica support, according to a process that is reported, is presented. A new chiral tetrahedral cluster (μ3-Se)RuCoW(CO)8C5H4C(O)CH32which was synthesized by the thermal reaction of the precursor (μ3-Se)RuCo2(CO)91with the functionally substituted cyclopentadienyl tricarbonyl metal complex anions [W(CO)3C5H4C(O)CH3]−is resolved on the amylopectin tris (phenylcarbamate) chiral stationary phases.

ISSN:1082-6076    

DOI:10.1080/10826079808006883

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A sensitive method for determining the total amount of sialic acid, glucosamine, and galactosamine in blood serum and glycoconjugates using reversed phase high performance liquid chromatography is described. Sialic acids present in glycoconjugates are released by acidic hydrolysis with 2 M TFA at 80°C for 2 h, whereas hexosamines are released following hydrolysis with 6 M HCl at 100°C for 8 h. The sialic acids released under these conditions are identified as a decarboxylated and deacylated product bearing a primary amino group (amino-product). Following removal of neutral monosaccharides and amino acids by ion-exchange chromatography on Dowex 50x8, the obtained amino-product and hexosamines are converted to Tosyl-derivatives. The obtained derivatives of amino-product, glucosamine, and galactosamine, are completely separated and determined on a Supelcosil LC-18 column by means of isocratic elution using a mobile phase of water-acetonitrile (85:15, v/v) and detection at 231 nm. The method shows a linearity range up to 25 nmol of sialic acids and hexosamines, has a detection limit ranging from 6 to 12 pmol, and is highly accurate when compared with literature values. The present method has the advantage of permitting determination of total sialic acid, glucosamine, and galactosamine in glycoconjugates and blood serum using the same HPLC conditions.

ISSN:1082-6076    

DOI:10.1080/10826079808006884

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A rapid, specific, and sensitive high performance liquid chromatographic method for the simultaneous analysis of eleven tricyclic imipramine-derived drugs has been developed by using a Lichrosorb RP Select B column, an isocratic system at ambient temperature, and UV detection at 230 nm. The influence of acetonitrile and methanol content, the molarity of sodium acetate, and the effect of adding counter-ion in the mobile phase have been investigated. Excellent separation of a mixture of the eleven compounds was accomplished within 30 minutes. The method was applied to pharmaceutical dosage forms containing a single active ingredient; any of the other compounds can be used as internal standard since these drugs are structural analogues and are generally not found simultaneously. Satisfactory results were obtained both for the recovery and the coefficient of variation.

ISSN:1082-6076    

DOI:10.1080/10826079808006885

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor