Diethylammonium Phosphate Buffer Solution pH 6.0

Dilute 68 mL of phosphoric acid R to 500 mL with water R. To 25 mL of this solution add 450 mL of water R and 6 mL of diethylamine R, adjust to pH 6 ± 0.05 (2.2.3), if necessary, using diethylamine R or phosphoric acid R and dilute to 500.0 mL with water R.