Robert A. Chalmers

Analytical applications of β-heteropoly acids : This influlsnce of complexing agents on selective formation

Abstract An explanation is given of the apparently paradoxical behaviour of heteropoly acids in the presence of organic complexing agents such as tartaric acid, and methods for selective formation of particular heteropoly acids are suggested. Sensitive and rapid methods for the determination of silicate and phosphate in the presence of each other are described.

Analytical applications of β-heteropoly acids : Part I. Determination of arsenic, germanium and silicon

Abstract The existence of two forms of several heteropolymolybdates, differing in structure and stability, was confirmed. The unstable β-forms were stabilised by addition of comparatively large amounts of polar organic solvents, especially acetone, presumably because the solvent displaces water from the surface of the heteropoly anion and so inhibits any reorganisation of the structure of the anion. The organic solvent also intensifies the colour. The methods are rapid, sensitive, precise and accurate. Various applications are described.

A method for the determination of phosphorus in organic compounds

Abstract The sample is decomposed by heating with nitric and sulphuric acids, the nitric acid is completely removed, and phosphomolybdic acid is formed under carefully controlled conditions of acidity and reduced to molybdenum blue by means of ferrous ammonium sulphate. The colour intensity is measured spectrophotometrically.

Systematic analysis by solvent extraction methods : Part I. Qualitative analysis

Abstract Methods are suggested for the systematic separation and determination of 12 metals by a combination of solvent-extraction and spectrophotometric methods.

Space-age analysis☆

A survey is given of present-day analysis, from an editorial point of view, and suggests that though techniques have changed in order to meet the challenges of modern technological advances and materials, the fundamental character of analytical research and its publication has not.

Development and publication of new gravimetric methods of analysis.

A review is made of the factors affecting the accuracy of gravimetric methods, and which need to be investigated in the development of new methods. Recommendations are made for writing up such investigations for publication.

Secondary standards : Acetylacetonates

Abstract The preparation of several acetylacetonates is described, the novel feature being that the organic reagent is added in substoichiometric amount. Several of the compounds are obtainable 99.9% pure or better, and are proposed as secondary standards for the metals they contain or for elementary analysis. These are the copper(II), chromium (III), zinc, cadmium, magnesium, thorium, cobalt(III), iron(II) and calcium compounds. Cobalt (II) and nickel dipyridine acetylacetonates are also proposed. Aluminium and beryllium acetylacetonates are suitable as routine test materials.

The stability constants of TAR and PAR complexes.

A discussion is given of the problem of ascribing dissociation constants in the hypothetical situation in which the protons of the hydroxy groups of TAR and PAR dissociate in the reverse of the normal order, and it is suggested that the o-hydroxy group should be regarded as intrinsically as acidic as the p-hydroxy group, and that the change in pK due to the internal hydrogen bonding is probably less than one unit.

Development and publication of new titrimetric methods.

Requirements are laid down for the development of titrimetric methods and for writing up the work for publication. The general principles of various types of titration reaction are discussed, and special attention is paid to the parameters which influence chemical reactions.

On the invention of conductimetric titration

In contrast to the earlier statement of one of the authors according to which conductimetric titration was invented by Küster and Grüters in 1903, it is shown that Ostwald made use of this analytical method as early as the nineties of the past century. Prior to Ostwalds work, however, papers appeared in which conductimetric curves were shown, with statements about their different characteristics in the case of reaction between weak and strong acids and bases. The first of these seems to be due to Kohlrausch [together with one of his co-workers, Kreichgauer (1885)]. It does not seem to have occurred to them, however, to use this phenomenon for the purposes of analytical chemistry, namely for titrimetry.