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Lyophilization, Concentration or Evaporation — Which is better for my Process? Lyophilization, vacuum concentration and vortex evaporation have many similarities but they are different processes, which lead to different outcomes. Deciding on what process is best for your sample can be an intimidating task. Lyophilization is used for multiple processes including long-term storage and sample preparation. Lyophilization dries the sample using sublimation — the conversion of water from the solid state (ice) directly to the gaseous state (water vapor) without going through the liquid state. Three steps are required in the lyophilization process: pre-freezing, primary drying and secondary drying. Each step is important, and needs to be complete for freeze drying to be successful. The eutectic temperature, or freezing point, of the sample must be known before starting the freeze Above: FreeZone -105˚C Freeze Dry System dry process. In order to freeze dry properly, the freeze dry collector must be 15˚ – 20˚ Celsius colder than the sample’s eutectic temperature. For example, water has a freezing point of 0° C. A freeze dryer with a collector of -15° C to -20° C or lower is required. If the sample is Acetonitrile, a -84˚C cascade freeze dryer is recommended. If the sample contains alcohols a -105˚C freeze dryer is needed. During primary drying, 92-93% of the moisture is removed from the sample. Labconco’s FreeZone® Freeze Dry Systems are available in collector sizes from 1 liter to 18 liters. FreeZone Systems are available in benchtop and console models and with collector temperatures of -50° C, -84° C and -105° C. Freeze drying can be a lengthy process taking anywhere from 12 hours to a week. Because of this, using a vacuum concentrator might be a better option. Vacuum concentration is a sample preparation process using centrifugal force, heat and vacuum to remove moisture from a sample. Vacuum concentration dries the sample using evaporation — the conversion of liquid to vapor. A cold trap is used in line to protect the vacuum pump and capture the solvent during the process. Vacuum concentrators take the sample to 99% dryness in a relatively short amount of time and can typically run any solvent regardless of freezing or boiling point. Labconco offers a full range of CentriVap® Vacuum Concentrators, including the exclusive Refrigerated CentriVap for heat sensitive samples such as RNA or proteins. Above: Refrigerated CentriVap Vacuum Concentrator Vortex evaporation also removes liquid to concentrate a sample for sample preparation. Unlike a vacuum concentrator, a vortex evaporator uses vortex motion instead of centrifugal motion. Because of the vortex motion, the analyte is washed down the sidewalls of the glassware increasing the recovery of the analytes being tested. Labconco offers two types of RapidVap® Evaporation Systems: one uses vacuum and one uses nitrogen blow down to speed evaporation. Sample sizes can be as small as 1 ml up to 450 mls per sample tube. Above: RapidVap Vacuum Evaporation System The Chart below will help with choosing the right process for your samples. FreeZone Micro liters to 6L Micro plates, micro centrifuge tubes, test tubes, flasks, serum bottles, bulk 12 hours – week Freeze Dryer, drying chamber, vacuum pump CentriVap Micro liters to 25mls Micro plates, micro centrifuge tubes, test tubes RapidVap 4.5mls – 450mls Test tubes, 170 ml & 600 ml tubes 25 minutes to 6 hours Concentrator, rotor, pump Accessories Glassware, adapters Pump type required Rotary Vane, Hybrid Applications Aqueous, protein, peptide, vegetation, environmental, HPLC, Pharmaceutical Cold Trap, CentriZap, glassware, secondary traps, additional rotors Rotary Vane, Diaphragm, Hybrid Peptides, DNA, Proteins, oligonucleotides, pharmaceutical 25 minutes to 6 hours Evaporator, Block, pump for Vacuum System, N2 regulator for N2 system Glassware, secondary traps, racks, additional blocks Diaphragm Sample Volume Range Sample Tube Size Processing Time Range Components Required Environmental, EPA, toxicology, biological, microbiology, food chemistry,