各位大神,EP药典中某原料药含量的方法是这样的:Dissolve 0.250 g in a mixture of 20 mL of dilute hydrochloric acid R and 50 mL of water R. Cool the solution in iced water. Carry out the determination of primary aromatic aminonitrogen (2.5.8), determining the end-point electrometrically.1 mL of 0.1 M sodium nitrite is equivalent to 27.83 mg of C12H14N4O2S.
其中2.5.8:Dissolve the prescribed quantity of the substance to be examined in 50 mL of dilute hydrochloric acid R or in another prescribed solvent and add 3 g of potassium bromide R. Cool in ice-water and titrate by slowly adding 0.1 M sodium nitrite with constant stirring.
检验方法就是将0.250 g溶解在20 mL稀盐酸R和50 mL水R的混合物中。将溶液在冰水中冷却。用电测法测定终点吗,2.5.8里的内容是什么意思?
2.5.8. DETERMINATION OF PRIMARY
AROMATIC AMINO-NITROGEN
Dissolve the prescribed quantity of the substance to be
examined in 50 mL of dilute hydrochloric acid R or in another
prescribed solvent and add 3 g of potassium bromide R. Cool
in ice-water and titrate by slowly adding 0.1 M sodium nitrite
with constant stirring.
Determine the end-point electrometrically or by the use of
the prescribed indicator.EP通则2.5.8里面的内容就这些