Persulfate Test Kits

Visual Kits

Range MDL Method Kit Catalog No. Refill Catalog No.
0-5.6 & 7-70 ppm as Na₂S₂O₈ 0.35 ppm Ferric Thiocyanate K-7870 R-7870



Persulfate is a strong oxidizer that is commonly used for clarifying swimming pools and spas and for the destruction of a broad range of soil and groundwater contaminants. Sodium persulfate is frequently used for environmental applications.


The Ferric Thiocyanate Method

Reference: D.F. Boltz and J.A. Howell, eds. Colorimetric Determination of Nonmetals, 2nd Ed., Vol. 8, p. 304 (1978).


CHEMetrics' persulfate test kit employs the ferric thiocyanate method. In an acidic solution, persulfate osidizes ferrous iron. The resulting ferric ion reacts with ammonium thiocyanate to form ferric thiocyanate, a red-orange colored complex, in direct proportion to the persulfate concentration. Chlorine does not interfere with this chemistry. Ferric iron, hydrogen peroxide, and ozone will interfere. Results are expressed in ppm (mg/L) sodium persulfate (Na2S2O8).