Freeze drying is a common used solution for long-term storage but can also be used as a sample prep step. In order to choose the right commercial freeze dryer, you need to consider a few things.
Total Amount of Moisture You Need to Remove
If you need to process 6L of total liquid, then you need a unit that can handle this. A larger one is always a good choice because at least 50% extra volume is recommended. Some accessories will only work with a unit that is 6L or larger, regardless of the size of the sample, so you need to make sure you are getting a unit that is big enough for your needs.
Types of Samples You Are Processing
Each component of the sample you are processing is important, so you need to think of the all the solutes or solvents that will be part of the samples. In order to have proper freeze drying, it requires a temperature differential of 15 to 30 degrees between the collector chamber and the sample’s freezing point. If samples are acidic, it can cause damages to the stainless steel coils. In this case, a PTFE coating is recommended to prevent any holes and rust in the collector. You can see some common freezing points of popular solvents and recommend collector temperatures online so you can make the right decision for your commercial freeze dryer.
Formats of Samples
Your accessories will need to match with the format of your samples. If your samples are in vials, then you need a clear chamber or tray dyer. If you are using bulk trays for your samples, then a bulk tray dryer or stoppering tray dryer can give you maximum capacity. For tubes and flasks, a port type drying chamber may be a necessity. Depending on the number of flasks used, there are different models available.
Is Transport or Long-term Storage Necessary?
Stoppering under vacuum can be necessary for transport or long-term storage. For large quantities that need to be processed, then you may need a stoppering tray dryer. A mini stoppering chamber with a port type freeze dryer can be used for small quantities. You want to make sure the unit can do all the steps of the freeze dry process, which includes a secondary dry.
Is a Vacuum Pump Required?
If a vacuum pump is necessary, then the pump will need to be selected based on the sample type. For standard aqueous samples, then a rotary vane pump will be sufficient. For solvents or acids, then it is recommended to get a hybrid type pump. You also need to make sure that the pump will meet the minimum specifications that are required for the lyophilizer.
