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The use of thin specimens for X‐ray microanalysis in biology
Author(s) -
Hall T. A.,
Anderson H. Clarke,
Appleton T.
Publication year - 1973
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.1365-2818.1973.tb04670.x
Subject(s) - microanalysis , computation , thin section , biological materials , microscope , microscopy , matrix (chemical analysis) , materials science , computer science , mineralogy , biological system , physics , optics , chemistry , biology , algorithm , composite material , organic chemistry
SUMMARY The quantitative X‐ray microanalysis of ultrathin biological sections is exemplified by a recent study of the distribution of calcium in mineralizing cartilage and bone. The determination of calcium mass‐fraction in one microarea of a vesicle within a section of rabbit epiphyseal plate cartilage is presented in detail in order to display all steps of the processing of the data. Mass fractions are obtained from an equation which is approximate but which is adequately accurate for most cases of interest, specifically for ultrathin biological sections where the analysed area consists predominantly of organic matrix. We shall examine the physical assumptions behind the computation, and the extent to which these assumptions have been verified in the analytical microscope. The purpose of this paper is to describe in detail the scheme of data collection and processing, which has now been in use for some years in the Cavendish Laboratory, for the measurement of local elemental mass fractions in thin biological specimens in instruments like the EMMA. After an outline of the physical theory we shall describe the handling of the data by means of working through an example of an actual measurement, and finally we shall add some comments, mainly precautions and reservations.