Fundamental Study on the Quantitative Analysis of Sulfide Minerals by Electron Probe Microanalyser (IV)

Comparative examination on the accuracy of quantitative analysis for sulfide minerals by the electron probe microanalyser has been carried out by the authors in these three years. Several results have been already reported in the first three papers of this series. The effect of the standard samples on the accuracy of analysis, and the relations between the accuracy, explained as relative error to the correct value, and an amount of correction (correction coefficient) are discussed in detail in this fourth report. As mutual relations exist cosely between relative errores and amounts of correction, the small amount of correction is desirable if possible. From the results of this examination, reasonable analytical data with acceptable accuracy will be given by using three component sulfide minerals as standard sample and the root mean square value of the relative error is 1.29%, then the error will be expected within 2.0% at the most. On the other hand, two component simple sulfide seems to be insufficient as standard sample, because the root mean square value of the error is so large as 3.43%. Analysis using standard sample which has a similar compsition to analysed specimen could give the most accurate value in the case of sulfide mineral analysis. The calibration curve method is also one of the best method for sulfide mineral because the root mean square value of the error shows fairly small value of 1.14% in our examinations.