Improvement of quantitation of biological X-ray microanalysis.

Absolute measurements of elemental concentrations within thin biological samples are often made by reference to a series of standards which resemble the samples in chemical and physical properties and the linear relationship between (p-b)/c and concentration. This principle requires that the chemical and physical properties of the matrix remain constant throughout a series of standards with different elemental contents and throughout different regions of the samples. Some of the changes undergone by specimens during X-ray microanalysis, e.g. loss of elements or organic mass loss, are also influenced by the composition of the matrix. A simple empirical modification to the linear (p-b)/c versus concentration relationship is presented to account for some of these effects and therefore improve quantitation of analyses.