ISO 3946:1982 Preview
Starches and derived products -- Determination of total phosphorus content -- Spectrophotometric method
This standard was last reviewed and confirmed in 2013. Therefore this version remains current.
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).