Stock Solution— Dissolve 34 g of monobasic potassium phosphate in about 500 mL of water contained in a 1000-mL volumetric flask. Adjust to pH 7.2 ± 0.1 by the addition of sodium hydroxide TS （about 175 mL）, add water to volume, ａnd mix. Dispense ａnd sterilize. Store under refrigeration.

For use, dilute the Stock Solution with water in the ratio of 1 to 800, ａnd sterilize.