Maintenance Tip: Freeze Dryers / Lyophilizers
To get the longest life out of your freeze dryer, experts recommend keeping up with basic oil changes on the vacuum pumps, neutralizing the stainless steel from acids, and cleaning the collectors as you would on a refrigerator. Most freeze dryers will last a long time with the proper care, however, if a major component such as a condenser breaks, it may be time to replace the unit.
Will the size or volume of samples to be lyophilized affect which style of freeze dryer should be used?
Yes. Two main configurations exist. Benchtop, which come in a variety of configurations and styles, are ideal for small volumes of samples which need to be accessed easily. Floor standing models, on the other hand, are beneficial for large scale freeze drying capabilities, such as large amounts of samples or bigger samples.
How does sample type affect which type of freeze dryer is ideal?
In order to properly freeze dry samples, a differential of 15-20°C between the eutectic temperature (freezing point) of the sample and the lyophilizer is needed. Most biological samples are sufficiently frozen by a standard system reaching -50°C. For samples such as HPLC preparations in acetonitrile, which has a eutectic point of approximately -42°C, a much lower temperature will need to be achieved. A cascade-type collector which can reach down to -84°C will be able to accommodate this. It should be noted that with many lab professionals switching to methanol for these processes due to its availability and affordability, an ultra-low temperature lyophilizer, able to hit as low as -105°C may be required due to methanol having a eutectic point of -97.6°C.
How does the volume of liquid to be removed affect the type of freeze dryer needed?
Different sample types hold differing amounts of water. A tissue sample may hold a small amount of liquid, whereas a food product may hold a much higher level of liquid. Using a lyophilizer that does not have sufficient capacity (for example freeze drying 6L of liquid in a 5L freeze dryer) can have detrimental effects on the system. This can result in damage to the system (increased collector temperature) and poor vacuum. Knowing the typical amount of liquid to be removed beforehand is therefore critical in purchasing the right system.
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