Developing A Vacuum Concentration Protocol

Efficient removal of solvents by vacuum concentration is a routine step for many analytical and isolation protocols. For the most part, protocols simply involve spinning the sample while applying a vacuum. The vacuum concentrator reduces the atmospheric pressure which in turn lowers the boiling point of the solution. The centrifugal force keeps the sample from boiling out of the tube, which is a phenomenon generally referred to as "bumping." However, some solutes are negatively affected by both temperature and solute concentration changes that occur during processing. For optimum yield and preservation of biological activity (when applicable), these parameters should be considered for each new solute and solvent combination.

Solute Properties and Guidelines for Concentration
The ease by which a solute can be concentrated is dependent upon the characteristics of the solute and solvent. A rugged molecule, such as DNA, is easily concentrated when in aqueous solution. It can be heated and concentrated to dryness and will still function properly when introduced into a cell. The characteristics of the solvent being vaporized have a major impact on the process as well. Volatile solvents are much easier to remove. However, the ease by which solvent is removed from a sample is secondary when compared to the resulting quality of the concentrated solute product.