US EPA Method 7197: Chromium, Hexavalent (Chelation/Extraction)
Method 7197 is approved for determining the concentration of dissolved hexavalent chromium [Cr(VI)] in Extraction Procedure (EP) toxicity characteristic extracts and ground waters. This method may also be applicable to certain domestic and industrial wastes, provided that no interfering substances are present. Method 7197 may be used to analyze samples containing from 1.0 to 25 µg of Cr(VI) per liter.