Destruction of the organic substances by digestion with a sulpho-nitric mixture and conversion of phosphates to orthophosphates. Formation of a phosphomolybdate. Measurement of the intensity of the blue colour at a wavelength of 825 nm. The method applies to contents up to 5 % (m/m).
Life cycle
NOW
PUBLISHED EN ISO 3946:1994 90.93
Standard confirmed Oct 13, 1999
