摘要:

Catecholamines can be determined coulometrically at constant-current electrolysis of 30 milliamperes in concentration corresponding to 1×10−9to 1×10−6equivalents per second of electrolysis time. Iodine - reagent is generated electrically and its amount is evaluated from a knowledge of the current and the generating time. This procedure is compared with the potentiometric method using a redox electrode.

ISSN:0003-2719    

DOI:10.1080/00032719308017443

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The single sweep oscillopolarographic behaviour of Rhodamine B in sulphuric acid medium was investigated. A novel, sensitive and selective catalytic method with oscillopolarography monitoring for the determination of ultratrace amounts of ruthenium was described, based on the catalytic effect of Ru(III) on the slow redox reaction occuring between Rhodamine B and potassium periodate in sulphuric acid medium at 25 °C. Single sweep oscillopolarography is used to monitor the changes in concentration of Rhodamine B by means of the second derivative wave at -0.55 V vs. SCE. The determination range from 8.2×10−10to 2.5×10−8M Ru was obtained by the initial rate procedure. Influence of 30 foreign ions was considered. Ru in ore samples was analysed by this method, with satisfactory results.

ISSN:0003-2719    

DOI:10.1080/00032719308017444

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Modifications of the AOAC thiamin and riboflavin methods allow effective and simple determination of both vitamins from aliquots of the digested sample of vegetable foods. Study of the minimum amount required for a complete hydrolysis of the vitamers corresponding to each vitamin have been carried out. A critical study of thiocrome formation which was later used in the spectrofluorimetric determination of thiamin was done. In order to separate riboflavin from the digested sample, a new liquid chromatographic method based on adsorption in florisil is proposed. The aforementionated methods were applied to different samples of several vegetable foods.

ISSN:0003-2719    

DOI:10.1080/00032719308017445

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A method is presented for the determination of copper, lead, iron, cadmium, cobalt and nickel in dialysis solution at μg/1 level by atomic absorption spectrometry after preconcentration. The preconcentration is based on chelate formation of the investigated metals with ammonium pyrrolydine dithiocarbamate and on retention of the chelates on Amberlite XAD-4 in a short column. The relative standard deviations for the determinations were found to be lower than 0.08.

ISSN:0003-2719    

DOI:10.1080/00032719308017446

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Adding additional components to supercritical carbon dioxide in supercritical fluid chromatography can extend or significantly alter the fluid solvating properties. Polar samples which are difficult to be analyzed with pure supercritical CO2because of their high polarity can be separated by adding polar modifiers to supercritical CO2. In this paper, a new mixing device using a teflon high capacity filter for adding polar modifiers to carbon dioxide mobile phase is introduced. This new mixing device could keep the amount of modifier in the mobile phase constant for a much longer time than a saturator column. The amount of water or methanol dissolved in supercritical CO2was measured by amperometric microsensor which is made of thin film of perfluorosulfonate ionomer(PFSI).

ISSN:0003-2719    

DOI:10.1080/00032719308017447

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A new fast dichromate method of water COD determination is proposed according to which a water sample premixed with a solution of dichromate in concentrated (95%) sulfuric acid is passed by pressure or vacuum through a glass column with a quartz packing heated up to 150–170°C during 3–5 min. The oxidation level of ϵ-caprolactam and adipic acid is 2–2.5 times more and the time of waste water analysis more than 30 times shortened as compared with the standard “reflux” and “semimicrotube” methods.

ISSN:0003-2719    

DOI:10.1080/00032719308017448

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

This work suggests a new algorithm for the elemental analysis, which permits taking into account both the multiplicative and additive matrix effects, a matrix composition being unknown. The use of this algorithm in the development of analysis techniques at any set of objects may appear to be successful at arbitrarily selected measurement conditions. The basis of the algorithm consists of a combination of pattern recognition and standard addition technique (PRSA). The main concept of PRSA is to predict a function approximating satisfactorily a calibration dependence for a specific object and then to determine an unknown concentration using a nonlinear addition technique, all the aforementioned being based on easily obtained information on an analyzed object and measurement conditions. The abilities of the proposed algorithm were demonstrated by the example of strontium determination by the flame atomic absorption spectrometry in superconducting systems.

ISSN:0003-2719    

DOI:10.1080/00032719308017449

出版商:Taylor & Francis Group    

年代:1993

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:10.1080/00032719308017432

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor