Vacuum and pressure filtration is used for sample preparation in chemistry, life sciences, environmental analysis, and pharmaceutical quality control. The goal is to separate a solid product from a liquid mixture or solvent.
Filtration rates are greatly enhanced by creating a differential pressure across the filter unit by applying either vacuum or pressure. The ultimate differential pressure requirements are generally low. When filtering at 100 mbar, 90% of atmospheric pressure is available to assist the filtration. Improving the vacuum level to 50 mbar (95% vacuum) has little appreciable effect on the differential pressure.
Solid phase extraction (SPE) is a sample preparation technique that is growing in popularity as it offers better yields than traditional liquid-to-liquid methods. A wide range of stationary phase forms is available to ensure rapid processing and automation.