| 摘要 |
Phosphites may be determined in solution in the presence of hypophosphites by mixing with an acidic solution containing a non-oxidising, non-reducing acid and an oxi-anion with a central metal atom capable of forming a heteropoly acid with phosphites, adding a reducing agent which reacts more readily with hypophosphite than with phosphite, whereby a coloured solution is formed, and measuring the colour intensity. Sufficient acid to prevent hypophosphite interference should be present. Specified anions are tungstate, chromate, vanadate and, as exemplified, molybdate. Specified reducing agents are ascorbic acid, isoascrobic acid, hydroquinone and p-methylaminophonol sulphate. The acid solution is generally above 4N, and sulphuric acid is specified. |
