The determination of 20–100 μmg. quantities of organic nitrogen

Abstract

Details are given of an ultra-micro method to estimate organic N, consisting of a digestion with sulfuric acid containing selenium as a catalyst, and direct addition of Russell''s reagents after neutralizing the digest. The method is applicable to a range 5 times smaller than any previous method. The standard error of a single determination is not greater than [plus or minus] 6.5% at 50 [mu]mg of N or over, and is [plus or minus] 8% for the range 5-20 [mu]mg of N. The method is readily applicable to the micro scale (1.0-10 [mu]g of N), when no special apparatus is required.