DETERMINATION OF NITROGEN USING A PERMEATION DEVICE

Abstract

The authors present a system to analyze nitrogen, presents as ammonium or nitrate ion, at concentration level of percent. The device can be easily converted into a FIA assembly and, consequently, can be used to improve the analytical frequency at a quality control laboratory. The determination is based on measurement of conductivity and standard addition method. A sample of commercial potassium nitrate, sold as fertilizer, was analyzed with good agreement with AOAC method, either using ammonium chloride or potassium nitrate as standard solutions, showing the robustness of the system. The detection limit, based on standard deviation of the blank, is 65.1 and 69.5 10-6mol L-1 for ammoniacal and nitric nitrogen, respectively.