Determination of total nitrogen in plant digests using a traacs 800 autoanalyzer

Abstract

Abstract A method is described, using a Traacs 800 AutoAnalyzer®, for the routine determination of total nitrogen in plant tissues. Nitrate in the plant sample was reduced with salicylic acid in an acid predigestion method. Then the total nitrogen was converted to ammonium sulphate in a Technicon BD40 Block digestor with concentrated hydrogen peroxide and a catalyst. Two methods, the Traacs 800 AutoAnalyzer® and the AutoAnalyzer (AA I) distillation method, were used to determine total ammonium content. The differences between the Traacs 800 and the AA I distillation methods ranged from ‐5.27% to 6.75% in ammonium content; the two methods were very closely correlated (r2 = 0.9934). The Traacs 800 can analyze plant total N up to 8.0%. Since the Traacs 800 system is three times faster than the AA I distillation method, handling 120 samples per hour, and possesses data processing capability, it is the preferred method.