Comparison of Total Nitrogen estimation by Kjeldahl Method and CHNS Analyzer in Dry Tropical Grassland

Abstract

The Dumas method (CHNS analyzer) is replacing the traditional Kjeldahl method as the method of choice for N analysis due to advancements in dry combustion nitrogen (N) analyzer technology and the high cost of disposing of hazardous laboratory waste chemicals. As a result, a comparison of the Dumas method (CHNS analyzer) with the Kjeldahl method is critical. Typically, such comparisons were conducted on a small number of distinct samples. The goal of this study was to compare the performance of instruments that use the automated Dumas method (CHNS analyzer) and the Kjeldahl method for N analysis of agricultural materials in a high-throughput laboratory setting. Using both instruments, N concentrations in manure, sewage sludge, plant tissue, plant seeds, and feedstuff fibres were determined. We collected samples for the analysis of organic matter from the horticulture area at the Banaras Hindu University campus in Varanasi, and total Nitrogen (N) was estimated using the Kjeldahl (wet oxidation) and Perkin-Elmer 2.400 Series II-CHN Mode techniques (dry oxidation or combustion). The positive correlation (r = 0.94**) of the Kjeldahl method with N- determination from a CHNS analyzer demonstrates that the method is practical for routinely determining the total nitrogen content of soils