Vanadium is precipitated from the strip solution, forming insoluble high-quality ammonium
metavanadate (AMV).
Phosphorus concentration was determined by
metavanadate colourimetry, and potassium concentration was determined by flame photometry.
Various methods have been reported in the literature which includes [BF.sub.3]-Si[O.sub.2] [8], (1-butyl-3-methyl imidazolium hydrogen sulphate [bmim]HS[O.sub.4]) [9], Ammonium
metavanadate [10], pyridinium-based ionic liquid [11], ionic liquid [12] and alum [13].
Vanadium also exists in extracellular fluids in the form of
metavanadate (+5 oxidation state).
Ammonium
metavanadate: An effective catalyst for synthesis of [alpha]-hydroxyphosphonates.
In order to prepare metal solution, 5 mmol of ammonium
metavanadate (NH4VO3) was dissolved in 30 mL of distilled water with constant stirring by a magnetic stirrer over a period of 5-6 h.
The most effective (and/or toxic) was sodium
metavanadate (NaV[O.sub.3]), whereas vanadyl sulfate showed a relatively mild action.
The synthesis was performed with a 0.468 g (4 mmol) mixture of ammonium
metavanadate in 18 mL of distilled water in an Erlenmeyer flask with magnetic stirring and heated at 70[degrees]C until it was dissolved.
Calcium and phosphorus concentrations were determined by ethylenediaminetetraacetic acid titration and the ammonium
metavanadate colorimetric method, respectively, and both are presented on the basis of dry-defatted weight [14].