Premium
Preparation of Biological Material For X‐Ray Microanalysis of Diffusible Elements
Author(s) -
Barnard Tudor,
Sevéus Lahja
Publication year - 1978
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/j.1365-2818.1978.tb00078.x
Subject(s) - diffusion , ice crystals , chemistry , microanalysis , evaporation , crystal (programming language) , x ray , analytical chemistry (journal) , crystallography , optics , chromatography , meteorology , physics , organic chemistry , computer science , thermodynamics , programming language
SUMMARY The appearance of ultrathin, dry‐cut cryosections of brown adipose tissue and liver was found to be strongly dependent upon adequate freeze‐drying. If freeze‐drying was inadequate, diffusion of substances could be demonstrated and freezing damage was not apparent. Diffusion was manifested as an electron dense film over structural features such as triglyceride droplet profiles and the edges of the section; when this film was thick, X‐ray signals for P, S, Cl, K and Ca could be detected from it, in different proportions to those found in the section. The frequency and intensity of diffusion were lowered by decreasing the temperature in the cryochamber from about 200 K ± 5 K to 163 K ±5 K by forced evaporation of liquid N 2 using an extra heater. The lowest incidence of diffusion was obtained in conjunction with this device, by leaving the sections in the cryochamber for at least 2 h during drying, either over a drying agent or under moderate vacuum. Such sections showed a narrow zone (A) at the edge that lacked obvious ice‐crystal damage, a thicker zone (B) of moderate ice‐crystal damage and the bulk of the interior (zone C) severely damaged by freezing. Qualitatively different, reproducible X‐ray spectra could be obtained from ultrastructural features even in areas showing some signs of diffusion.