Measurement of sorption kinetics by gravimetric moisture sorption is well known for not being a fast analysis method.
Whereas residual moisture content determination by Karl Fischer titration or water-activity measurements are completed within a relatively short period of time, water vapor sorption may take several days depending on the sorption kinetics of the sample material.
Providing an optimized surface to volume ratio by preparing the sample as a thin layer in a larger dish may at least save some valuable measuring time by avoiding bulk effects. The sorption kinetics of the material itself, however, cannot be changed.
In this Application Note, L-lysine monohydrochloride (L-lysine HCl) was used as model system to demonstrate that speeding up a sorption analysis might lead to risky misinterpretation of results.
Hydration was measured in the Moisture Sorption Analyzer SPSx-1µ.
The measurement time and equilibrium conditions were varied to demonstrate their effects on moisture sorption and analysis results.
