Hexavalent chromium salts are used in numerous industrial processes. They are also used extensively as corrosion inhibitors in open and closed cooling water systems.
The Diphenylcarbazide Method
References: APHA Standard Methods, 22nd ed., Method 3500-Cr B - 2009. ASTM D 1687-02, Chromium in Water, Test Method A.
With the chromate test method, hexavalent chromium reacts with diphenylcarbazide under acid conditions to form a red-violet color. Results are expressed as ppm (mg/L) CrO4.
Kit comes in a plastic case and contains everything needed to perform 30 tests: Refill, Low and High Range Comparators, Acidifier Solution, 25 mL Sample cup, and instructions.
Range: 0-1 & 1-10 ppm
MDL: 0.05 ppm
Method: Diphenylcarbazide