Standard Mercury Solution— Prepare from Mercury Stock Solution as directed under Method I. Each mL of the Standard Mercury Solution contains the equivalent of 1 µg of mercury.
Standard Preparation— Pipet 2.0 mL of Standard Mercury Solution into a 100-mL beaker, and add 35 mL of water, 3 mL of sulfuric acid, and 1 mL of potassium permanganate solution. Cover the beaker with a watch glass, boil for a few seconds, and cool.