Answer to Question #159972 in General Chemistry for jahanvi

Question

As coming to the structure of Norepinephrine bitartrate it contains an Amine group (PKA value 8.85 which is a weak base) and two phenol groups (PKA value one at 9.50 and one at 12.65 which are weakly acidic). Overall it is an ionizable drug. But as per the rule of PH selection, the ph value should be at least 2 units above or two units below the PKA value. So the PH can be either in the range of 6.8 or 8.8 (if we consider the PKA value of Amine). But why we use a strong acidic ph range (3 to 5) to analyze Norepinephrine bitartrate in HPLC.

Answer 1

Because Hydrolysis of this salt would result in a pH <7.