摘要:

An infrared detector for High Pressure Liquid Chromatography has been developed. The infrared source is a helium-neon laser which emits at 3.39 microns. Flow-injection analysis of all classes of lipids is performed using 100% chloroform as a solvent. HPLC separation of triglycerides, cholesterol esters and cholesterol is done using a silica-based column. Detection limits for the triglycerides and cholesterol esters are determined with the absorptivities calculated from the calibration curves of these compounds.

ISSN:0003-2719    

DOI:10.1080/00032718808082019

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Dibenzo-18-crown-6-potassiwn ferricyanide and dibenzo-18-crown-6-potassium ferrocyanide complexes are separated on a C18reversed phase column and determined by combined liquid chromatography-flame atomic absorption spectrometry in μg/ml range with a precision of 3.37–3.63%.

ISSN:0003-2719    

DOI:10.1080/00032718808082020

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The presence of the Down syndrome (DS) protein in the sera of individuals is associated with a higher than average risk of parenting a child with Down syndrome. The protein has been determined to be a lipoprotein and is presumably a variant of β-lipoprotein.

ISSN:0003-2719    

DOI:10.1080/00032718808082021

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A simple and sensitive procedure for the simultaneous determination of cephacetrile and ceftezole in a mixture is presented.

ISSN:0003-2719    

DOI:10.1080/00032718808082022

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Results are presented on the development of a new procedure for the preconcentration and analysis of the eleven phenolic compounds covered by the E.P.A. 604 method. This new procedure is applied to synthetic sea water samples, previously adjusted to pH 2, using stearylamine and hexadecyltrimethylammonium bromide as surfactants and concentrating the pollutants in a small volume of di-isopropyl-ether. Experimental conditions have been optimized by means of a procedure previously published by the authors, that makes use of the simplex algorithm. Under the final conditions established recoveries for the investigated compounds range within 80–95 %, except for phenol, only 60 % of which is recovered.

ISSN:0003-2719    

DOI:10.1080/00032718808082023

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The possibilities of determining benzidine, 3, 3′ -dimethyl-benzidine, 1-naphtylamine and 2,4-diaminotoluene with coulo-metrically generated bromine were studied. Conditions have been found for an indirect determination of 3,3′-dimethylben-zidine and 2,4-diaminotoluene based on the reaction with excess bromine. With 3,3 -dimethylbenzidine, the unreacted bromine is reduced with excess arsenic (III) that is back-titrated with coulometrically generated bromine. With 2,4-diamino-toluene, the excess bromine is titrated with copper (I) that is coulometrically generated in the same base electrolyte after changing the polarity of the generating electrode. Analytical use of the reactions of benzidine and 1-naphtylamine with bromine is prevented by non-stoichiometric courses of the reactions.

ISSN:0003-2719    

DOI:10.1080/00032718808082024

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A simple method is described for the determination of residual organic acids, used as catalyst neutralizers, in alkylphenolethoxylates. The detection limit is 12 ppm. Method validation data is included. Commercially produced surfactants were analyzed and found to contain acetate in the range 600 ppm to 2300 ppm.

ISSN:0003-2719    

DOI:10.1080/00032718808082025

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The solubility of silver nitrate in the chromatographic support solvents, glycerin, ethylene glycol and 1,3-propanediol has been determined at 25°C, in the absence and presence of 5% water. The solubilities are reported as mole fractions, molality and molarity of silver nitrate. The solubilities in the solvents increase in the order: 1,3-propanediol < ethylene glycol < glycerin. These solubility data allow estimation of the amount of silver nitrate on the column support.

ISSN:0003-2719    

DOI:10.1080/00032718808082026

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

An extraction study of 36 cations with SAIH into isoamyl alcohol in the presence of EDTA, ascorbic acid and IN HC104showed that only Mo(VI) gave a stable yellow colored complex extractable into the organic phase. This effect was used for the selective extractive spectrophotometric determination of Mo(VI) in the presence of other tested cations.

ISSN:0003-2719    

DOI:10.1080/00032718808082027

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A hollow cathode discharge has been applied to the determination of Nd, Ho, Er, Tm and Y in solutions using copper cathodes and argon as a carrier gas. The solutions were evaporated to dryness in the cathodes without a pretreatment. Absolute detection limits for the elements studied here were found to be lower in the copper cathode by about one order than those obtained in previous studies in graphite hollow cathodes.

ISSN:0003-2719    

DOI:10.1080/00032718808082028

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor