Low-Temperature Specimen Preparation

Low-temperature specimen preparation is not to be considered solely in the context of hydrated biological systems, although much of what will be discussed here will be directed toward these types of samples. Low temperatures are an essential prerequiste for studying naturally frozen materials such as snow and ice and frozen foods such as ice cream (Fig. 14.1). The technology is central to the preparation of aqueous systems such as paints, suspensions, emulsions, solutions, soils, clays, muds, and cements; of any nonaqueous liquid systems such as oils and organic liquids; and even of gases, vapors, and volatile materials. In addition, as has been shown in Chapter 12, low temperatures may play an important part in the preparation of plastics, polymers, and elastomers. The common physical parameter of these diverse samples is that they all can be solidified, provided the temperature is below their melting point. Once solidified they can then be further manipulated for subsequent examination and analysis in electron beam instruments.