Diffusion methods of the separation of fluoride are of very great importance for the determination of fluorine in biological and other materials. They involve liberating fluoride ions by mineral acids and their absorption in trapping solutions of alkali. As diffusion vessels, polyethylene bottles (1, 2), Conway dishes (3, 4), multicell trays (5), polyethylene stoppers (6), special dishes with two square chambers (7), and plastic Petri dishes (S) are used. In most diffusion methods, silicone grease is used to seal diffusion vessels in order to prevent any leakage of fluoride (4, 5, 7, 9,10). Polyethylene bottles and stoppers only need not be sealed; nevertheless, sealing bottles with wax was also recommended (2). Recently, Taves (10) found that fluoride passes into trapping solutions in the form of methylfluorosi lane if silicone grease is used for sealing; the diffusion of hydrogen fluoride was supposed earlier. In the presence of the simpliest silicone, hexamethyldisiloxane, the separation of fluoride is much more rapid. Therefore, a faster diffusion method for the separation of fluoride was proposed (8). Fluoride was liberated by 25% perchloric acid in the presence of a solution of hexa-
Sugar-beet was grown using ammonia solutions and urea as nitrogen fertilisers The influence of fertiliser type and time of application on the amino acid composition and mineral content in sugar-beet roots when harvested is discussed.
IntroductionPULP from sugar-beet roots has high nutritional value and is often used in mixed animal feeds. A knowledge of the amino acid composition and the mineral content is important in evaluating the quality of sugar-beet root pulp for this purpose. Although data on the composition of some animal feeds are available, 132 there is a lack of quantitative information on the composition of sugar-beet roots as influenced by soil types, fertiliser treatment and climatic conditions. The aim of the present study is to find the optimum time of fertiliser application and the type of fertiliser treatment which will give the required amino acid composition and mineral content of sugar-beet roots.
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