Nonaqueous titration of sulfates of quinine and quinidine using barium acetate.

ABSTRACT

A nonaqueous titrimetric method is proposed for determining the diastereomeric sulfates of quinine and quinidine. The sulfuric acid content of the alkaloid salts is precipitated, in the form of barium sulfate, with acetous barium acetate solution before the liberated alkaloid is titrated; the necessary calculations are provided. A favorable characteristic of the proposed procedure is the accuracy, speed, and ease of performance. The mean percent recoveries (p = 0.05) obtained with the proposed method for the sulfates of quinine and quinidine were 98.84 +/- 1.00 and 99.74 +/- 1.27, respectively, compared with 100.73 +/- 1.44 and 100.82 +/- 1.16, respectively, when the BP 1968 procedure was applied.