Division 3.15 Concentrated solution of tryptophan (3.2), c = 2,5 μmol/ml:

In a 500 ml volumetric flask dissolve 0,2553 g tryptophan (3.2) in hydrochloric acid (3.13) and make up to the mark with hydrochloric acid (3.13). Store at - 18 ^oC for a maximum of 4 weeks.