Abstract
LONDON Society of Public Analysts, Feb. 3.—N. L. Allport and G. H. Skrimshire: A new method for the determination of lead in organic substances, with special reference to dyestuffs. The organic material is destroyed by wet oxidation and the lead is removed by shaking with a chloroform solution of diphenyl-thiocarbazone. Finally the lead is determined colorimetrically as sulphide. The method is applicable in the presence of large amounts of iron, but bismuth interferes with the method, and special procedures are necessary when appreciable amounts of tin, aluminium, nickel, or cobalt are present.—B. S. Evans: (1) Some analytical applications of sodium hydrosulphide. A rapid and accurate method is described of separating tin from various other metals the sulphides of which are soluble in alkali cyanide. (2) A rapid method of dissolving lead alloys preparatory to the determination of tin and antimony. Lead dissolves rapidly and completely in a mixture of perchloric and phosphoric acids, whilst tin and antimony form insoluble compounds which are apparently of the nature of ‘metastannic’ and ‘metantimonic’ acids.—H. B. Dunnicliff and H. D. Suri: The phloroglucinol method for the determination of mechanical wood pulp in paper. The phloroglucinol method of Cross and Bevan was found to be unreliable in India, and the authors have therefore studied the effect of temperature on the results, the relationship between the volume of standard reagent and the weight of paper for quantitative reactions, the time required, and the mechanism of the reaction.—E. H. Bunce: Investigations relating to milk standards under the Burma Food and Drugs Act. There are no legal standards for milk in Burma, but in the Government Laboratory a minimum of 3 per cent of fat and 8.5 per cent of solids-not-fat is adopted for cow's milk, and a minimum of 5 per cent for fat and 9.0 per cent for solids-not-fat for buffalo's milk. A common fraud is the dilution of buffalo milk with water to imitate cow's milk.
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Societies and Academies. Nature 129, 518–520 (1932). https://doi.org/10.1038/129518b0
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DOI: https://doi.org/10.1038/129518b0