The standard is suitable for the determination of dis olved (ortho)phosphate and the total content of phosphorus compounds in water with a P content of at least 0.01 mg/l. Note Interference may occur with SiO2 contents of at most 60 times the phosphorus content. Iron and copper do not interfere in levels up to 10 mg/l. Vanadium(V) and chromium (VI) interfere, the interference caused by arsenic (V) can be eliminated by conversion to arsenic(III). Sulfide does not interfere in levels up to 2 mg/l. At higher sulfide contents, the sulfide interference can be eliminated by expelling hydrogen sulphide gas from the acidified sample using nitrogen.
NEN 6479-1981 history
1981NEN 6479-1981 Water - Photometric determination of the content of phosphorus compounds