Freeze drying and freeze substitution combined with low temperature-embedding. Preparation techniques for microprobe analysis of biological soft tissues.

An X-ray microanalytical and morphological investigation was carried out on rapidly frozen freeze-dried or freeze-substituted tissues. A comparison was made between different embedding and polymerisation procedures following freeze substitution and freeze drying. The investigation also included an analysis of specimens which had been infiltrated, embedded and polymerised by ultraviolet irradiation at low temperatures with Lowicryl-HM20. The method of freeze drying, followed by embedding and polymerisation at low temperatures in vacuo was found to give satisfactory results, comparable with more tedious and hazardous freeze substitution technique.