TOTAL PHOSPHOROUS QUANTITY DETERMINATION METHOD

摘要

The disclosed method determines the total phosphorous quantity in test water safely and in a short time period by breaking down phosphorous compounds included in test water and converting to phosphate ions, and then determining the quantity of phosphate ions in the test water. In the method, first sulfuric acid and alkali metal salts of peroxodisulfuric acid are added to test water, and the mixture is heated for a prescribed time period at a temperature from 65˚C to boiling temperature. A colour former formed from an aqueous solution is added to the test water, said aqueous solution containing at least one hydroxyl group-containing compound selected from the hydroxyl group-containing compound group consisting of hydroxyl carboxylic acids and alditol, a vanadium compound having a vanadium valence of 3-5, a non-reducing oligosaccharide capable of generating a 5 carbon aldose, a 6 carbon aldose or a 6 carbon ketose by means of decomposition, and a 7-molybdic acid 6-ammonium, and after heating the test water to at least 65˚C for a prescribed time period, the light absorbance of the test water for an arbitrary wavelength occurring in the range of 600-950nm is measured.