A Method for the Direct Determination of Organic Nitrogen by the Kjeldahl Process.

One of the most conspicuous recent advances made in sewage analysis in this country may be said to be the development of a direct process for the determination of the nitrogen as ammonia.1 The greater simplicity of the technique, the greater economy of time effected by the elimination of distillation, and the relatively greater accuracy of the process are salient advantages of the direct method which surely cannot fail to be of moment in the routine work of sewage laboratories. To be able to apply a direct process to the determination of the ammonia formed in the determination of total organic nitrogen by the Kjeldahl process seemed the next step toward greater simplicity and rapidity of execution. During a considerable portion of the work at Columbus a direct process was in daily use for the determination of the nitrogen as ammonia, and a more intimate knowledge was gained of local conditions as to the disturbing factor of turbidity, to which, as we all know, has been chiefly due the indifferent success attending earlier attempts at the direct nesslerization of the acid digestate of the Kjeldahl process. Under such circumstances it was thought that a direct method for determinating nitrogen by the Kjeldahl process might be successfully developed. Working along lines by which a direct process for the determination of the nitrogen as free ammonia was successful under such unusually hard water conditions as prevailed at Columbus, a method was finally obtained by which the disturbing turbidity was completely eliminated. It is our purpose to discuss the several factors which have to do with the turbidity occurring in nesslerized tubes, and further to describe a direct method for determination of nitrogen by the Kjeldahl process, found applicable under Columbus condi-