The diphenylcarbazide (DPC) method is a common colorimetric analytical method for determining hexavalent chromium in a solution. Diphenylcarbazide, a chromogenic reagent, is added to the sample. In the presence of hexavalent chromium, diphenylcarbazide reacts to form a deep violet complex that exhibits an absorption peak at a characteristic wavelength. The intensity of the color development is directly proportional to the concentration of hexavalent chromium in the sample. This color change is then measured using photometry or spectrophotometry to quantitatively determine the concentration of hexavalent chromium. The diphenylcarbazide method is a simple, sensitive, and cost-effective way to analyze hexavalent chromium in a variety of samples. It is frequently used in environmental laboratories and industrial facilities for monitoring chromium concentrations.