Seveus L
Scan Electron Microsc. 1980(4):161-70.
X-ray microanalysis allows "in situ" studies on ;the elemental composition of the cell and its compartments. The reliability of the results is almost entirely determined by the preparation method. Two criteria for a reliable preparation method have been formulated: (1) it must preserve the ultrastructure to permit identification of cellular compartments, (2) it must retain the elements in their in vivo location. We investigated cryoultramicrotomy and confirmed its validity as a preparation method for X-ray microanalysis of diffusible elements. The method is only truly reliable, however, under the following conditions: (1) the tissue must be frozen rapidly, (2) the sections must be cut in the ice crystal free surface layer, (3) the sections must be cut at low temperature (e.g. a specimen temperature of -140 degrees C, a knife temperature of -100 to -120 degrees C and a cryochamber temperature under -100 degrees C, and pressed onto the grid and freeze-dried at a temperature of -100 degrees C).
X射线微量分析可对细胞及其各部分的元素组成进行“原位”研究。结果的可靠性几乎完全取决于制备方法。已制定了可靠制备方法的两个标准：（1）它必须保留超微结构以允许识别细胞各部分，（2）它必须将元素保留在其体内位置。我们研究了低温超薄切片术，并证实了其作为可扩散元素X射线微量分析制备方法的有效性。然而，该方法仅在以下条件下才真正可靠：（1）组织必须快速冷冻，（2）切片必须在无冰晶的表面层切割，（3）切片必须在低温下切割（例如，标本温度为-140摄氏度，刀温为-100至-120摄氏度，冷冻室温度低于-100摄氏度），并压在网格上，在-100摄氏度下冷冻干燥。
