INVESTIGATIONS ON THE SOLUBILITY OF MOLYBDATOPHOSPHATES .2. COMPARISON OF THE SOLUBILITIES OF VARIOUS MOLYBDATOPHOSPHATES RECOMMENDED FOR THE DETERMINATION OF PHOSPHATE

Phosphorus-32 has been used to evaluate the solubility of the molybdatophosphates of a number of protonated organic nitrogen bases under the conditions prevalent during gravimetric determination of phosphate. The values were measured in acid medium (HCl) in the presence and absence of citrate and were found to be in the order of magnitude of 10-6 to 10-9 mole/l. The degree of precipitation is usually >99.99% for phosphate quantities between 2 and 50 mg. The amount of phosphate remaining in solution after precipitation was not found to influence either the accuracy or the precision of the determination, although the values tended to show a fairly large degree of scattering. © 1979 Springer-Verlag.