What is azeotropic distillation?
In pharmaceutical analysis, azeotropic distillation is one of the techniques used for water determine. Toluene and xylene is the most common water-immiscible solvents for azeotropic distillation to determine water in biological samples. Water distills with the solvent and separates form the immiscible solvent after condensation. Then water is measured by volume. Azeotropic distillation provides a better and accurate measurement of total water content than drying for two main reasons. The first one is that water can be completely removed from the sample using this method. In addition, the results are not affected by volatile impurities other than water in the sample.[1]
What is azeotropic distillation applied to?
When azeotropic distillation was developed, this technique was considered to be the most accurate for the determination of moisture in products. Consequently, this method has been employed as a referee technique to establish conditions for moisture measurement by simplified methods used for control analysis.
[1] Handbook on bioethanol: Production and Utilization, Charles Wyman, 1996.
