title: Improved precision of quantitating calcium in biological electron probe analysis.
abstract: We describe the use of direct multiple least-squares fitting of (unfiltered) biological X-ray spectra. Test of this method on computer-generated spectra and experimental specimens shows that, for the average biological specimen, direct fitting improves the precision of Ca measurements by an approximate factor of 1.6 for a given electron dose. The influence of non-statistical, instrumental sources of measurement errors is considered, and we show a simple method for reducing the effect of these sources of error in the directly fitted spectra.
authors.affiliation: Department of Molecular Physiology and Biological Physics, University of Virginia, P. O. Box 800736, Charlottesville, VA 22908-0736, USA. rh4c@virginia.edu
authors.forename: R
authors.initials: R
authors.lastname: Ho
authors.forename: Z
authors.initials: Z
authors.lastname: Jia
authors.forename: A P
authors.initials: AP
authors.lastname: Somlyo
authors.forename: Z
authors.initials: Z
authors.lastname: Shao
mesh_terms: D000818:Animals; D002118:Calcium / Q000032:analysis*; D004577:Electron Probe Microanalysis / Q000379:methods*; D006801:Humans; D013048:Specimen Handling
chemical_list: D002118:Calcium