Standards for quantitative energy dispersive X-ray microanalysis of biological cryosections: validation and application to studies of myocardium.

The preparation of a comprehensive set of gelatin-glycerol-salt standards for quantitation of diffusible ions in ultrathin cryosectioned tissue is described. This set of standards serves two basic functions. The first is to calibrate the X-ray analytical system so that peak-to-continuum ratios obtained from test specimens may be converted to elemental concentrations. The second is to provide a known set of elemental concentrations which can be used to check the performance of the preparative and analytical steps involved in thin section biological X-ray microanalysis. The application of these standards and techniques for cryoultramicrotomy and analysis of myocardial tissue also is described.