Total unoxidized nitrogen

Recovery of 50 fig, NH3-N by the total unoxidized nitrogen technique was quantitative from waters of all salinities. It would seem, therefore, that the salt that accumulates from highly saline samples when the volume is reduced during digestion has no deleterious eflFect on the technique. 

Replication of the total unoxidized nitrogen technique for unfiltered Bay water samples was generally poor (Table II). Usually, out of ten replicates, there were one or two unusually high values and all efforts to eliminate them failed, including mixing for several minutes in a highspeed Waring blender. 

Since the total unoxidized nitrogen technique gave excellent reproducibility for membrane filtered Bay water, it would seem that the poor reproducibility of the technique for unfiltered samples is because of inhomogeneity caused by uneven distribution of suspended matter. 

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