May 10,1924 
Nitrate and Ammonia in Nitrogenous Materials 
529 
are to be determined, it is preferable to use the larger amounts of water and rea¬ 
gents specified and collect more distillate. 
The principal change from Strowd’s method is that the reduction is allowed to 
proceed for several hours before the solution is heated and the time of preliminary 
heating is increased. Some arrangement like the Bunsen valve permits the dis¬ 
tilling apparatus to be utilized in the meantime for other purposes. The other 
modifications which prescribe a larger amount of alloy, a longer period of prelimi - 
nary heating and larger volume of distillate, provide better conditions when rela¬ 
tively large amounts of nitrate are to be determined. The writer is of the opinion 
that the preliminary reduction before heating is the most important change made 
in Strowd’s procedure, however, as excellent results have been obtained on some 
samples of moderate nitrate content by otherwise conforming to his directions. 
Experiments have been made with the modified procedure to test the following 
points: (1) A possible loss of ammonia in the preliminary reduction; (2) its 
efficiency compared with the regular Strowd method for the reduction of re¬ 
latively large amounts of pure nitrate; (3) the recovery of added nitrate in the 
presence of tobacco; (4) a comparison of the two procedures for nitrate in 
Tobacco; (5) a comparison of the modified Strowd and the Ulsch-Street methods 
for nitrate in fertilizers and (6) a comparison of the nitrogen obtained in the 
control determinations by the modified Strowd and Ulsch-Street methods with 
that found by the official magnesium oxid method for ammoniacal nitrogen in 
fertilizers. 
Blank determinations were made and deducted in reporting the results in the 
tables on all of the above work. 
LOSS OF AMMONIA IN THE PRELIMINARY REDUCTION 
For this work either Baker’s analyzed ammonium sulphate or Eimer and 
Amend’s tested ammonium chlorid were used. They were assumed to be pure, 
were practically moisture-free but no analyses were made to verify their com¬ 
position inasmuch as they were to be used for a comparative study of the two 
methods for ammonia recovery. As the results obtained on both salts were 
•equally close to the theoretical, no distinction is made in their discussion. For 
the determination, separate weighings of 0.4 gm. of the former salt or 0.3 gm. 
of the latter were used. These amounts are theoretically equivalent to 0.0848 
gm. and 0.0785 gm. of nitrogen, respectively, representing more nitrate than 
would ordinarily be present in a determination. Control determinations were 
made by the modified method in which either the ammonium salt or Devarda 
alloy were omitted. When the ammonia salt was omitted the results were 
negligible, with or without the alloy. The recovery of ammonia from ammonium 
salts in the absence of the alloy is shown in Table I, C and E. 
Determinations were also made by the modified method, connecting the 
flasks with the condenser instead of the Bunsen valve during the 24-hour 
digestion at room temperature. These are indicated in Table I, D and E. 
At the writer’s request, duplicate determinations were made in the same manner 
by H. D. Spears, of this station, and his results were within the range given 
.and are included in the averages under these headings in Table I. 
The results by the modified method indicate a slightly better recovery of the 
ammonia by the use of the Bunsen valve compared with those where the flask 
was connected at once with the condenser as shown in B and D. Neither are as 
good, however, as those found by the Strowd method. In the determinations 
where the alloy was not used as shown in C and E, the results were just the 
reverse, in fact the average of those in E or with the condenser are better than 
those found by the Strowd method. 
