Concentrating Heat Sensitive Samples Without Degradation

By Jenny Sprung, Product Manager

Typically, sample concentration or solvent evaporation requires heat to drive the evaporation process. For heat sensitive samples, adding too much heat can damage or modify the structure of  the analyte. The most effective way to safely evaporate solvent from heat sensitive samples is to place the sample in a vacuum atmosphere. At reduced pressure, the evaporation phase change occurs at a lower temperature, allowing the sample to be concentrated without damage from excessive heat.

Common laboratory methods for solvent evaporation or sample concentration are lyophilization (also known as freeze drying), vacuum evaporation, nitrogen blow down and rotary evaporation. Several factors determine the optimal method for concentrating heat sensitive samples — sample volume, sample quantity, required temperature range, and solvent(s) being evaporated. These sample concentration methods and factors will be addressed in the following discussion.