Analytical Chemistry of Periodates

Perchlorates can be determined gravimetrically by fusion with ammonium chloride in a platinum crucible, extracting the chloride formed with water and precipitating AgCl as before. 

However, analysis of periodates is more important and is therefore discussed below. The procedure is similar to that described for iodates and a mixture of the two can be analysed. 

In a buffered alkaline solution, periodate oxidises iodide to iodine and it is reduced to iodate. On the other hand, in acid solution, iodate oxidises iodide to iodine, which can be titrated against standardised Na2S203 solution. 

---