Calibration of transmission electron microscopic mass determination using objects with known mass distribution

Abstract
SUMMARY: An improved calibration procedure is described for dry mass determination methods, that are based on microdensitometry of transmission electron micrographs. Polystyrene latex spheres, that are supposed to have a homogeneous mass distribution, are used for the calibration procedure. By computer fitting of the theoretically expected mass distribution to the distribution measured in a line through the centre of a sphere, a mass calibration factor is obtained. The number of measurements required for a predetermined calibration accuracy can be decreased considerably as compared to other calibration methods. Accurate calibration and reproducible adjustment of the electron optical magnification are required.