S.L. 437.82 Art. 5to 1 050 i.u. acid (4.7) and to 4,5 with with water and dilution with

STANDARD SOLUTIONS

Weigh out a quantity of standard zinc bacitracin (4.11) corresponding (according to the activity indicated). Add 5 ml of 0,1 M hydrochloric leave to stand for 15 minutes. Add 30 ml of water, adjust the pH phosphate buffer (4.5) (about 4 ml), make up to a volume of 50 ml mix well (1 ml = 21 i.u.). From this solution prepare by successive phosphate buffer (4.5) the following solutions: s8 0,42 i.u./ml s4 0,21 i.u./ml s2 0,105 i.u./ml s1 0,0525 i.u./ml