Basic biological X-ray microanalysis

As more scanning and transmission electron microscopes become equipped with x-ray detectors, increasing numbers of scientists and technicians will be trying to obtain elemental data using the myriad of specimen preparation methods and quantitative procedures that have been developed over the past 28 years. This paper is an introduction to the basic concepts of biological x-ray microanalysis for new investigators in this field. The general principles of specimen x-ray emission, x-ray nomenclature and specimen preparation techniques for x-ray microanalysis are explained with specific examples. A simplified approach to estimating the x-ray excitation volume in a biological bulk or sectioned matrix is given. Some of the common detector and microscope artifacts are described and illustrated. Included in this paper is a short discussion of the effective use of controls and standards and references for some of the current methods for making ones own standards.