An automated method for the simultaneous determination of nitrogen and phosphorus in plant material, sludge and soil

This paper describes the semi-automated method which involves controlled digestion with sulfuric acid of up to 40 samples in a thermostatically regulated heating block, followed by automatic calorimetric analysis of the digest solutions for both ammonia and orthophosphate concentrations. Nitrogen and phosphorus are determined in concentration ranges of 0-2. 25 percent and 0-0. 75 percent respectively.