High-vacuum condensation drying of proteins from the frozen state

Abstract

1. Methods are described for the preservation by desiccation from the frozen state of large volumes of protein, both in bulk and in ampoules.2. The principle is one of high-vacuum condensation drying, utilizing liquid air for quantities up to 250 c.c. or refrigerator evaporator coils for quantities up to 5 l. Desiccators, not manifolds, are used throughout.3. Use is made of an accurate automatic control of heat to the frozen material. By recording this heat input a visual record is obtained indicating when the end-point of desiccation has been reached, and, furthermore, it is possible to calculate from this record the approximate percentage dryness of the material at any period of desiccation.4. The control of the apparatus is such that within stated limits the conditions of desiccation can be altered at will.5. In this form of apparatus obstruction to the flow of water vapour is so small that plugged containers may be used, thus preventing contamination of the material while it is being dried.6. In its final form the apparatus is entirely automatic and the running costs are extremely low.7. Suggestions are made for designing forms of apparatus to meet many requirements.