Estimation of NH₄-N, NO₂-N, NO₃-N and Total N Using the Chemifold III with Same Set of Tubes and Modifications in Apparatus for Degassing

A modified method for estimation of nitrite and nitrate is being proposed using flow injection analyser (FIAstar Tecator). It can be integrated with ease along with the estimation of ammonium and total Kjeldahl nitrogen on the same chemifold with the same set of tubes. The minimum detectable concentration of nitrate, (5 mg kg⁻¹), by the proposed method was same as that of standard method but the maximum detectable limit was ten times higher. Satisfactory degassing of the reagents was also achieved using ordinary filter paper in the modified apparatus instead of polymer filter disc. By using the proposed modification, the use of different chemifolds and polymer disc can be dispenced. This would remarkably reduce the basic as well as operational cost of the equipment.