It can be a mistake if you do not select a system that is designed for your type and size of samples. Below is a quick step by step guide to help you with the selection process.
Select Condenser Temperature based on the Sample’s Eutectic Point
The difference in temperature between your sample and the condenser is the driving force of lyophilization. It is very important that the condenser be at least 20°C colder than the sample’s eutectic or freezing point. The condenser collects the vapors before they reach the vacuum pump. If the condenser is not cold enough to collect the vapors the vacuum pump can be damaged and samples may not stay frozen during lyophilization
Select Model of Freeze Dryer for your Sample Size
Freeze Dryers have 3 important specifications in regards to size. Make sure the model you select will accommodate the size of sample you intend to lyophilize and the number of samples you need to load at the same time. The Specifications are: Volume that is removed in 24 hours, Amount of ice the condenser will hold before defrosting and Volume the condender can accomodate at one time when loading.
Select Vacuum Pump & PTFE Coatings
If your samples contain solvents, acids or corrosive compounds it is important to ensure your Freeze Dry System is able to accommodate these harsh compounds. A PTFE coated condenser is recommended for acids. A Freeze Dry System requires a vacuum level of 2 x 100- 2 mBar. An Oil Pump works well with aqueous samples but can be damaged if exposed to solvents or harsh chemicals. Scroll or Hybrid pumps are recommended when freeze drying solvents and harsh chemicals.
Select Drying Accessories
A wide variety of drying accessories are available to ensure your samples are processed according to your needs. Common drying accessories are different sized Drying Chambers with flask ports or trays, Manifolds for flask or ampules, and Tray Dryers with or without Stoppering.
Freeze drying samples doesn’t have to be difficult if you do your homework and choose the correct freeze dryer from the start.
For further information, visit www.labconco.com where you will find details on each system as well as instructional videos, or call 800.821.5525.
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