Direct Acidimetric Analysis of Papaverine in Concentrated Lithium Chloride Solution

Abstract

Hydrochloric acid was used as the titrant for papaverine base in two different media: (a) 18.5% ethanol and 81.5% 8 M lithium chloride solution, and (b) 10% tetrahydrofuran, 5% ethanol, and 85% 8 M lithium chloride solution. Per cents were calculated on a weight to weight basis. All of the titrations were carried out potentiometrically and the end points were determined by the first derivative method. It was found that bromophenol blue indicator could also be used to determine end points in medium a. The mean per cent recovery for the titrations in medium a, with the end points determined by the first derivative method, was 98.85 with a standard deviation of 0.69. In the same medium, using bromophenol blue for end point determination, the recovery was 99.48 with a standard deviation of 0.96. In medium b, the recovery was 100.02 with a standard deviation of 1.27.