This standard specifies the method for determining hexavalent chromium content in plastic materials, with its core approach being "colorimetry." The method involves extracting the sample using simulated sweat or acidic sweat, followed by a specific color reaction between the extracted hexavalent chromium and diphenylcarbazide (also known as diphenylcarbazone) as the chromogenic agent. The absorbance of the solution is then measured at a wavelength of 540 nm using an ultraviolet-visible spectrophotometer or a similar photometer. By comparing the results with a standard curve, the hexavalent chromium content is quantitatively determined. This method provides a unified technical basis for detecting the permissible limits of this harmful substance in plastic products, particularly those that may come into contact with human skin.