Thiosulfate Test Kits

Visual Kits

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, 22nd ed., Method 4500-SO3 2- 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.