Color spectrometry for determination of P
Nature of complex -- Coordination of molybdate ions with P as the central coordinating ion.
1. H3PO4 + 12 H2MoO4 ? H3P(Mo3O10)4 + 12 H2O
yellow blue
2. Reduce Mo6+ to Mo3+ to form a blue color.
3. Read absorbance (A) at 880 nm wavelength)