|Range||MDL||Method||Kit Catalog No.||Refill Catalog No.|
|5-50 ppm||5.0 ppm||Iodometric||K-9705|
Thiosulfate is an excellent reducing agent. It is used primarily as an antichlor, or chlorine-removing agent, in various chemical processes, including the bleaching of pulp, paper, and textiles.
Reference: APHA Standard Methods, 23rd ed., Method 4500-SO32- B- 2000.
CHEMetrics’ method employs the iodometric chemistry. Thiosulfate is titrated with iodide-iodate titrant in acid solution using a starch indicator. Although sulfite usually titrates as thiosulfate, the sample is pre-treated to inhibit sulfite interferences. The kit contains a sulfamic acid solution which can be used to prevent nitrite interference. Results are expressed as ppm (mg/L) S203.