Comparison of Various Methods for Water Activity Determination

• Published in: Chemical engineering & technology Vol. 29; no. 11; pp. 1311 - 1315
• Main Authors: Dette, S. S., Ulrich, J.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01-11-2006; WILEY‐VCH Verlag; Wiley-VCH
• Subjects: Applied sciences; Chemical engineering; Determination; Exact sciences and technology; Solvents; Water activity; Relative humidity; Test method; Heat of fusion; Hardness; Density
• ISSN: 0930-7516; 1521-4125
• DOI: 10.1002/ceat.200600104

The water activities at the transition point of ten inorganic hydrates were determined by different techniques. The techniques used were compared and evaluated aiming to identify which one is the most efficient. It could be shown that measuring the relative humidity is an easy, accurate, direct, and low‐priced method and as such more efficient than other methods tested (measuring the density, hardness, and heat of fusion).
The objective of this work was to find an efficient method for determining the water activity at the transition point of hydrate crystals. Different methods for the determination of water activity were studied in terms of their potential, and the advantages and disadvantages are discussed.