Determination of Ammonia in the Blood

The estimation of ammonia in the blood is a difficult matter not. only because ammonia is present in very minute quantities, but also because it is rapidly split off from some labile components of shed blood. The removal of the ammonia by means of an air current is subject to a source of error in as much as the amount of ammonia recovered may vary with the rapid&y of the aeration and the temperature.’ Besides, the color produced by Nesslerization is too weak to be compared in the calorimeter unless the apparatus is specially adjusted for the purpose,2 while the microtitration of Barnett? requires considerable manipulation which makes the method somewhat cumbersome. The method which we developecJrd:,:b?’ ‘Xts laboratory (with the % view of future application to the study o, some problems) seeks to avoid these disadvantages. In the first place, t.he blood proteins are precipitated as soon as the blood is taken to prevent the splitting off of ammonia. Secondly, the ammonia in the blood filtrate is absorbed with the aid of permutit? which, of course, does away with the necessity of driving off the ammonia by aeration. Furthermore, by the addition of a measured quantity of ammonia to the filtrate, it is possible to examine the color produced by the Nesslerization without changing the calorimeter. Before this procedure was adopted for the determination of ammonia in the blood, we performed many tests wi,th solutions of albumin in Ringer’s solut.ion to which st,andard ammonium sulfate