R.J. Magee

Analytical applications of infra-red spectroscopy : The behaviour of the oxinates of niobium, tantalum and associated elements

Abstract The behaviour of the oxinates of niobium, tantalum and associated metals in the infra-red region was studied and a method developed for the determination of niobium and tantalum. Vanadium caused no interference, but other heavy metals, such as molybdenum, manganese and cobalt, which interfered were removed by preliminary treatment when the method was applied to the determination of niobium and tantalum in steels.

Spectrophotometric determination of platinum after extraction of thestannous-chloro complex by high molecular weight amines

Abstract An investigation of the complex formed between platinum(IV) and tin(II) in hydrochloric acid solutions has been carried out, and its extractibility by various long-chain high molecular weight amines (HMWA) in organic solvents examined. The orange coloured platinum(IV)-tin(II) complex is quantitatively extractable from an aqueous phase into an organic phase of a wide range of high molecular weight amines in chloroform or benzene. On the basis of this extractability a method has been developed for the spectrophotometric determination of platinum in the presence of many other elements. Comparison of the absorption spectra of the coloured species in the aqueous and amine phases indicates the presence of the same absorption species in each medium. The extractability of the complex by HMWA suggests that the coloured species is anionic and not cationie as reported by earlier authors.

Some aspects of the polarographic behaviour of technetium and rhenium

The oxidation-reduction behavior of technetium was investigated polarographically by means of ultramicro methods. Rhenium was examined as a control and a guide. The behavior of technetium was found to be similar to that of rhenium more than to that of manganese. (C.J.G.)

Determination of copper in sea water by atomic absorption spectroscopy

Abstract A commercial atomic absorption spectrophotometer is used without modification to establish the most suitable operating conditions for the determination of copper. Using the direct method of spraying aqueous solutions of copper into the flame, the minimum copper which can be determined is about 25 μg/litre. However, this method is not suitable for determining copper in sea water. A method based on the extraction of the copper-ammonium pyrrolidine dithiocarbamate complex into ethyl acetate and spraying of the organic extract into the flame is satisfactory, and it gives a marked increase in sensitivity.

Determination of rhenium and technetium by infrared spectroscopy

Abstract The determination of μg amounts of rhenium, as perrhenate, and technetium, as pertechnetate, by infrared spectroscopy is described. The species are precipitated with tetraphenylarsonium chloride in presence of potassium perchlorate as carrier; the precipitate is filtered, dried, and pressed with potassium bromide into a disc for examination. The tetraphenylarsonium complexes of perrhenate and pertechnetate show strong sharp bands at 10.94 and 11.09 μ respectively.

The anion-exchange separation of technetium, rhenium and manganese

Abstract An anion-exchange method for the separation of technetium, rhenium and manganese is outlined. After sorption on the resin column, manganese is first eluted with hydrochloric acid, rhenium with ammonium thiocyanate in hydrochloric acid, and technetium by means of nitric acid. In the eluates rhenium is determined colorimetrically and technetium radiochemically. As little as 10 μg of technetium in the form of potassium pertechnetate can be separated from 15 mg of manganese as potassium permanganate and 0–8 mg of rhenium in the form of potassium perrhenate.

The separation and identification of manganese, technetium, rhenium, ruthenium and molybdenum on the ultramicroscale

Abstract A scheme is presented for the separation and detection of manganese, technetium, rhenium, ruthenium and molybdenum on the ultramicroscale. A number of comfirmatory tests for these elements on this scale have been investigated and the results are reported. A survey of reagents suitable for the approximate estimation of technetium, rhenium and molybdenum has been carried out and these are combined in a separation scheme for these elements.

Spectrophotometric studies on technetium and rhenium

Abstract The behaviour of technetium and rhenium with three reagents, potassium ferrocyanide, sulphosalicylic acid, and α-picolinic acid is discussed. With the first reagent, technetium and rhenium in the presence of bismuth amalgam or stannous chloride, form coloured solutions which show maximum absorption at widely different wavelengths, thus permitting the spectrophotometric determination of both elements in the presence of one another. As little as 2 μg of technetium can be determined by this method. Sulphosalicylic acid with pertechnetate which has been reduced with stannous chloride produces an orange-red coloration suitable for the determination of the element. The method has the advantage that the element can be determined in the presence of fairly large amounts of rhenium, manganese and molybdenum. When pertechnetate is reduced with ascorbic acid, α-picolinic acid yields a yellow-red solution which provides a sensitive method for the spectrophotometric determination of the element. The types of complex formed with the reagents are discussed.

The analytical chemistry of the pyridine thiocyanates—III: The separation of rhodium, palladium and platinum

Abstract A procedure is described for the separation and subsequent colorimetric determination of rhodium, palladium and platinum through the formation of complex and ammine-type thiocyanates, using solvent extraction. Suggestions are put forward as to the nature of the complexes in solution.

The analytical chemistry of the pyridine thiocyanates—II: The separation of ruthenium and palladium

Abstract A procedure is described for the separation and subsequent colorimetric determination of ruthenium and palladium as complex and ammine-type thiocyanates respectively, using solvent extraction. Suggestions are put forward as to the nature of the ruthenium complex occurring in solution.