Standardless quantitative electron-excited X-ray microanalysis by energy-dispersive spectrometry: What is its proper role?

Electron beam X-ray microanalysis with semiconductor energy-dispersive spec trometry (EDS) performed with standards and calculated matrix corrections c an yield quantitative results with a distribution such that 95% of analyses fall within +/-5% relative for major and minor constituents. Standardless methods substitute calculations for the standard intensities, based either on physical models of X-ray generation and propagation (first principles) o r on mathematical fits to remotely measured standards (fitted standards). E rror distributions have been measured for three different standardless anal ysis procedures with a suite of microanalysis standards including metal all oys, glasses, minerals, ceramics, and stoichiometric compounds. For the fir st-principles standardless procedure, the error distribution placed 95% of analyses within +/-50% relative, whereas for two commercial fitted standard s procedures, the error distributions placed 95% of analyses within +/-25% relative. The implication of these error distributions for the accuracy of analytical results is considered, and recommendations for the use of standa rdless analysis are given.