Van Slyke determination

Van Slyke determinations for primary amino groups were unsuccessful. 

Problem 36.15 The reaction of primary aliphatic amines with nitrous acid gives a quantitative yield of nitrogen gas, and is the basis of the Van Slyke determination of amino nitrogen. What volume of nitrogen gas at S.T.P. would be liberated from 0.001 mole of (a) leucine, (b) lysine, (c) proline — ... 

Van Slyke determination. Treatment of primary aliphatic amines and a-amino acids with nitrous acid and volumetric determination of evolved nitrogen. 

A pentapeptide on complete hydrolysis yields 3 moles of glycine, 1 mole of alanine, and 1 mole of phenylalanine. Among the products of partial hydrolysis are found H Ala GlyOH and H Gly Ala OH. What structures are possible for this substance on the basis of its giving no nitrogen in the Van Slyke determination ... 

The improved methods introduced in the years 1940 to 1945 created new possibilities in this field. The Van Slyke method for quantitative determination of amino acids, based on the measurement of the volume of carbon dioxide evolved in the course of the reaction between amino acids and ninhydrin (V2), was much more reliable than the older methods. At the same time the microbiological methods designed for amino acid determinations (D3, S6) made possible the detection of very small concentrations of these compounds. The application of these... 

VI. Van Slyke, D. D., and Kirk, E., Comparison of gasometric, colorimetric, and titrimetric determinations of amino nitrogen in blood and urine. J. Biol. Chem. 102, 651-682 (1933). 

In 1927, Van Slyke devised a micromethod using urease. Instead of determining ammonia released by alkali from ammonium carbonate, carbon dioxide was liberated after acidification. This was successfully... 

A common biological determination is for amino-acid nitrogen. This determination is made by the van Slyke method, in which the amino groups (-NH2) in protein material react with HN02 to produce N ga< volume of which is measured. A 0.530 g sample of a biological material containing glycine,... 

V6. Van Slyke, D. D., MacFadyen, D. A., and Hamilton, P. H., The gasometric determination of amino acids in urine by the ninhydrin-carbon dioxide method.. Biol. Chem. 150, 251-258 (1943). 

The method may be run with either plasma or serum. The recommended rate is forty determinations per hour, which utilizes about 0.3 ml of sample. It has been shown35 that the method has given thoroughly adequate correlation with the results of the manometric Van Slyke technique. 

Seligson, D., An automatic pipetting device and its application in the clinical laboratory. Am. J. Clin. Pathol. 28, 200-207 (1957) see also Seligson, D., and Marino, J., Automatic pipetting attachment for the Van Slyke manometric apparatus for C02 determination. Clin. Chem. 4, 120-126 (1958). 

Van Slyke, D. D. (1911). A method for quantitative determination of aliphatic amino groups. 

Up to this time, little attention had been paid to the possibility of phosphoamide links because, in 1910, Levene and Jacobs had shown that the (three) primary amino groups (of the purines and the cytosine) are presumably not substituted in the nucleic acid since they can be determined by van Slyke s method. However, in 1936, Bredereck hydrolyzed ribosenucleic acid (Boehringer) by boiling an aqueous solution of the substance, and isolated a very small amount of material which was described as amorphous, monobasic, and readily hydrolyzed to guanine and uridylic acid. He therefore decided it was a guanine-uridylic acid and assigned it the following structure. 

The molar buffer capacity as defined by van Slyke is determined only by the ratio acid/salt, and is independent of the total concentration of either component. C. Morton has proposed a measure of buffer capacity in terms of the dilution effect. He defined capacity /3 as... 

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