Ammonia nitrogen and albuminoid nitrogen in sewages, soils, and other
materials of high nitrogen content may be satisfactorily determined by
diluting the sample with ammonia-free distilled water and proceeding as
described in the preceding sections, but it is permissible to distill
with steam.[40]
_Procedure._—Use a 200 cc. long-necked Kjeldahl flask connected with a
condenser so that the distillate may drop from the condenser tube
directly into a Nessler tube or a flask. Connect the Kjeldahl flask with
a steam generator by a tube reaching almost to the bottom of the flask.
After the apparatus is freed from ammonia put the sample to be tested
into the flask. Use 10 to 100 cc. of the sample according to its ammonia
content. Pass ammonia-free steam through the liquid in the Kjeldahl
flask and collect the distillate in the usual way. It is usually
convenient to collect the distillate in a 200 cc. flask and to take an
aliquot part of it for Nesslerization. Compare with standards and
calculate the nitrogen content in the usual manner.
This method has the advantage, when the sample is treated with an
alkaline solution of potassium permanganate, of avoiding bumping,
permitting the assay of solid matter, and yielding the ammonia more
rapidly than by the ordinary process of distillation.