Total nitrogen determination in plant material by means of the indophenol-blue method.

Abstract

[123.17.02]The indophenol blue method for the determination of NH3 in digests of plant material is modified by the introduction of a dilution step, which is necessary because of the sensitivity of the method, and the use of a phosphate buffer to suppress pH influence caused by slight variations in the acid content of the digests. EDTA is used to prevent the precipitation of hydroxides and phosphates in the alkaline region. The method is quick and simple since no heating is required for colour development. The straight calibration curve obtained permits direct automatic registration of the results. (Abstract retrieved from CAB Abstracts by CABI’s permission)