How to determine chromium impurities in silicon dioxide powder

The determination of chromium impurities in silicon micropowder can refer to the determination method of chromium in soil.

Principle: After the silicon dioxide powder containing chromium is digested with acid, the chromium in it is oxidized to hexavalent chromium, and then it is detected by spectrophotometry or atomic absorption spectrophotometry. DPC spectrophotometry is commonly used. Chromium in the sample was oxidized to hexavalent chromium by potassium permanganate in acidic medium, and the hexavalent chromium reacted with diphenyl carbazide (DPC) to generate a purplish red compound, which was determined by spectrophotometry at the wavelength of 540nm.

If the chromium content is low, it needs to be detected by atomic absorption spectrophotometry with higher accuracy. In fact, at present, the use of spectrophotometry has been less, because the big instrument of atomic absorption has been very popular now, and the most commonly used one is atomic absorption spectrophotometry.

See the environmental standard HJ 49 1-2009 Determination of Total Chromium in Soil by Flame Atomic Absorption Spectrophotometry for specific operation methods.