Determination of the optimum working range from a calibration curve for colorimetric analysis with an "autoanalyzer"

A study has been made of the types and distribution of errors in determining the optimum working range from a calibration curve for automated analysis. Three error equations are derived for the fitting of a linear, quadratic or cubic curve, involving a thorough statistical analysis of the data. The errors from a set of silica and alumina standards, requiring a quadratic and cubic fit respectively, compare favourably with replicate analyses of standard rocks done on a previous occasion.