GB/T 15555.4-1995 standard specifies the determination method of hexavalent chromium in solid waste leaching solution, using diphenylcarbazide Spectrophotometric method, spectrophotometry. It is suitable for the determination of the sample is 50 mL, using a 30 mm optical path Colorimetric dish, the detection limit is 0.004 mg/L; when using a 10 mm optical path Colorimetric dish, the upper limit of the determination is 1.0 mg/L. The standard describes in detail the influence of interfering substances such as colored turbid liquids, oxidation reduction substances and organic matter on the determination, as well as the interference of molybdenum, mercury, vanadium and other elements and treatment methods. The determination principle is that hexavalent chromium reacts with diphenylcarbazide under acidic conditions to form a purple-red complex. The measurement is carried out by Spectrophotometric method, spectra-trophotometry at a Maximum absorption wavelength of 540 nm. All reagents used must meet the analytical purity requirements of national or professional standards.