US EPA Method 7198: Chromium, Hexavalent (Differential Pulse Polarography)
This method is used to determine the concentration of hexavalent chromium [Cr(VI)] in natural and waste waters and in EP extracts. The method can quantitate chromium in concentrations of up to 1.0 mg/L to 5.0 mg/L, depending on the mercury drop size. Higher concentrations can be determined by dilution.