摘要:

This paper introduces a kinetic method based on the oxidizing action of vanadate ion on 1,8-diamino-4,5-dihydroxyanthraquinone-2,7-disulfonic acid. The reaction between these two species is monitored spectrophoto-metrically at 602 nm. The kinetic parameters of such a reaction are also reported. The calibration graph has two linear segments in the ranges 2.5–4.5 and 7.3–50 μg/mL of vanadium, respectively. The interferences of foreign ions in the determination have been studied and the proposed method has been applied to the determination of non-volatile vanadium in two crude oils.

ISSN:0003-2719    

DOI:10.1080/00032718808071931

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A sensitive and precise method for the determination of microgram amounts of zinc (II) has been developed. The ion associate of the anionic zinc (II)-thiocyanate complex with malachite green (MG) can be floated with the aid of small nitrogen bubbles, then dissolved in toluene. The formation of the ion associate takes place over a wide pH range (3-7). The method permits the determination of zinc (II) in the range 0–1.1 jig/ml and can be applied to samples of drinking water with good results.

ISSN:0003-2719    

DOI:10.1080/00032718808071932

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The determination of primary structure of proteins is still an important and challenging task. The Edman reaction, using phenyl isothiocyanate as the N-terminal labelling agent and making available the N-terminal amino acids as PTH-derivative, lies at the core of all modern sequencing strategies. TLC, however, can be considered to have several advantages over other methods of chromatography because it is sensitive, simpler, and inexpensive, and allows the elution of compounds for subsequent use. The present paper reports the TLC separation and identification of PTH-amino acids in a fifteen component mixture. TLC plates (20×20cm × 0.5mm) were prepared by spreading slurries of silica, gel impregnated with sulphate, acetate, phosphate and chloride of zinc; and sulphates of Mg, Mn, Fe and Co. The chromatograms were developed in pre-equilibrated, rectangular glass chambers using several binary and ternary solvent systems. The spots were located by exposing the chromatograms to iodine vapour. The PTH-aminoacids being weak bases, combine with proton and finally form pairs with available anions (like Cl-, SO4.-, CH3COO-) and the solubility and adsorption of the ion pair affects the chromatographic behaviour. The methods are reproducible, simple, require less time and offer resolution of several difficult combinations. The spots are very compact and Rfcan be measured very correctly, for identification purpose, in comparison to iodine-azide method where bleached spots with diffused boundaries on a light brown background are located. Attempts were also made to determine the partition coefficients and correlate them with hRfvalues.

ISSN:0003-2719    

DOI:10.1080/00032718808071933

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A three-electrode, high pressure liquid chromatographic column was developed for electrochromatography. The application of a potential to a carbonaceous stationary phase/working electrode affects the retention of various solutes. Carbon tetrachloride, methylene chloride, toluene, phenol, and pyridine were test solutes. Capacity factors for these solutes were measured as a function of applied potential. Acetonitrile, containing various supporting electrolytes, was the mobile phase.

ISSN:0003-2719    

DOI:10.1080/00032718808071934

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

ISSN:0003-2719    

DOI:10.1080/00032718808071935

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0003-2719    

DOI:10.1080/00032718808071920

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor