摘要:

Palladium(II) forms 1:1 and 1:4 complexes with allyl thiourea. The molar composition of the complexes was determined by molar-ratio and continuous variation methods and confirmed by means of elemental analysis of the compounds isolated from solution.

ISSN:0003-2719    

DOI:10.1080/00032718408059843

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The polarographic behavior of some organic dyes such as nitro-benzo-triazol, amino-nitro-benzo-triazol, benzo-triazol azo thionaphthene carboxylic acid and 5-methyl imidazol 2-methyl benzo-triazol in aqueous buffered media has been studied. The results reveal that the reduction reactions occurred irreversibly under diffusion-control. The reduction mechanism of nitro-benzo-triazol and amino-nitro-benzo-triazol involve the consumption of six electrons in the form of one wave in acid and two waves in alkaline media. The electro-reduction of benzo-triazol azo thionsphthene carboxylic acid consumes four electrons. The mechanism proposed for that compound indicates that the triazol centre forms a radical as an intermediate state in alkaline medium. The reduction process of 5-methyl imidazole 2-methyl benzo-triazol contains two consumed electronic in acid media while four electrons are consumed in alkaline media.

ISSN:0003-2719    

DOI:10.1080/00032718408059844

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The overall formation constants of the Cd (Trimethylene-diamine) system were determined by differential pulse polarography at 25°C and at μ = 1 (NaNO3). The percentage distribution of cadmium present in various forms as a function of ligand concentration was calculated.

ISSN:0003-2719    

DOI:10.1080/00032718408059845

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The toxicological literature often mentions that chromium(VI), present and added to cements for technical reasons, induce dermatosis. Good analytical techniques are not available. The D.P.P. method proposed here for the microdetermination of chromium (VI) in cements is fast and selective. The cation is solubilized by stirring the cement with distilled water. After filtration, the solution is submitted to differential pulse polarography. Generally, samples analysed contain between 1 and 12 mg of chromium (VI) per kg of cement. The potential peak is -0.19 V v.s. S.C.E. for the pure chromium (VI) solution and is shifted toward between -0.25 and -0.30 V v.s. S.C.E. when chromium (VI) is extracted from real cement samples The detection limit is 0.3 ppm.

ISSN:0003-2719    

DOI:10.1080/00032718408059846

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The electrochemical reduction of piroxicam has been investigated on a mercury pool in acidic and alcaline media.

ISSN:0003-2719    

DOI:10.1080/00032718408059847

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

An aerosol deposition technique for sample introduction for the determination of manganese by electrothermal atomization atomic absorption spectrometry is described and evaluated. A calibration between deposit time and injected volume of sample can be constructed. The analytical charecteristic concentration can be increased significantly by increasing the deposition time for samples of low matrix concentration.

ISSN:0003-2719    

DOI:10.1080/00032718408059848

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

A sensitive and selective method for the extraction and spectrophotometric determination of Zr(IV) with N-p-chlorophenyl-3,4-,5-trimethoxycinnamohydroxamic acid (PTCHA) has been developed. The binary complex of Zr(IV)-PTCHA is extracted from 2–6 M HCl into chloroform, having a maximum absorbance at 385 nm; molar absorptivity 2.1 × 1041 mol−1cm−1. A ternary complex with xylenol orange (Zr-PTCHA-XO) have been studied in chloroform-ethanol media, which absorbs at 540 nm; molar absorptivity 4.3 × 1041 mol−1cm−1. The present method is applied for the analysis of zirconium in standard samples.

ISSN:0003-2719    

DOI:10.1080/00032718408059849

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Traces of copper(II) can be quantitatively extracted from aqueous thiocyanate solutions into 2-benzoylpyridine-2-pyridyl-hydrazone (BPPH) or 2,2′-dipyridyl-2-pyridylhydrazone (DPPH) chloroform solution. Optimal conditions given for the extraction are based on a critical study of the relevant factors such as the effect of the pH, thiocyanate and reagent concentration. Very small amounts of copper can be recovered from large sample volumes and determined directly.

ISSN:0003-2719    

DOI:10.1080/00032718408059850

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Pentafluorophenyldimethylsilyl chloride (flophemesyl chloride, F1) is a well known derivatization reagent for improved electron capture detection (ECD) in gas chromatography (GC)(GC-ECD), but it has never been utilized for improved detectability and sensitivity in GC-photoionization detection (GC-PID). We have now utilized a wide variety of flophemesyl alcohol derivatives in order to show a new approach for realizing greatly reduced minimum detection limits (MDL) of virtually all alcohol derivatives in GC-PID analysis. This particular derivatization approach is inexpensive and easy to apply, leading to quantitative or near 100% conversion of the starting alcohols to the expected flophemesyl ethers (silyl ethers). Detection limits can be lowered by 2–3 orders of magnitude for such derivatives when compared with the starting alcohols, along with calibration plots that are linear over 5–7 orders of magnitude. Specific GC conditions have been developed for many flophemesyl derivatives, in all cases using packed columns. Both ECD and PID relative response factors (RRFs) and normalized RRFs have been determined, and such ratios can now be used for improved analyte identification from complex sample matrices, where appropriate.

ISSN:0003-2719    

DOI:10.1080/00032718408059851

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

A method was proposed in which the retention indexes (RI) defined on the n-alkane scale were measured by using 1-phenylalkane homologous series as reference compounds. Good agreement was observed between the RI values obtained with this method and those determined using n-alkanes as the reference. An attempt was made to predict the RIs based on the additivity for the constitutive atomic groups. The RIs were estimated with considerable accuracy by using increments of substituents themselves and positional increments between substituents. It was possible to distinguish methylnitroaniline isomers by comparison of the calculated RI values with the observed values.

ISSN:0003-2719    

DOI:10.1080/00032718408059852

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor