An Improved Gasometric Apparatus for Estimation of Amino Nitrogen

The first apparatus for the quantitative determination of amino nitrogen was devised by Sachsse and Kormann. 1 It consisted essentially of a cylinder for deaminizing the aliphatic amine and a buret for purifying and measuring the nitrogen. Mallet 2 described minor modifications in the form of the apparatus. Brown and Millar 3 proposed an elaborate set-up for carrying out the amino nitrogen determination. Van Slyke 4 devised an apparatus giving satisfactory accuracy yet requiring only relatively simple manipulations. Klein 5 described an all glass deamination chamber to replace the bottle and tubes first used by Van Slyke. Later, Van Slyke 6 not only made use of this feature but also added a motor shaking mechanism which, together with the gas buret and Hempel pipet, was mounted in the form familiar today to the many users of his amino nitrogen apparatus. A little later Van Slyke 7 devised his micro apparatus which, except for size, is similar to the larger form. Kupelwieser and Singer 8 and Koch 9 modified the deaminizing chamber to prevent possible losses of nitrogen. Van Slyke 10 published a description of his manometric apparatus and Folley 11 made a new design of the gasometric apparatus. Here a continuous all glass system eliminates the use of rubber connections through which there is a possibility of nitrogen leakage.

The new design of the amino nitrogen apparatus presented here is believed to be more satisfactory than previous forms. We have recognized the inherent deficiencies and the empirical nature of the determination. Quantitative accuracy in the determination of some amino acids is possible only when the temperature, the rate of shaking the deaminizing chamber, the time allowed for deamination, the value for the blank, and other factors are under precise control.