Practical Considerations on Indirect Calibration in Analytical Chemistry

Abstract

Indirect or methodological calibration in chemical analysis is outlined. The establishment of calibration curves is introduced and discussed. Linear calibration is presented and considered in three scenarios commonly faced in chemical analysis: external calibration (EC) when there are no matrix effects in the sample analysis; standard addition calibration (SAC) when these effects are present and internal standard calibration (ISC) in cases of intrinsic variability of the analytical signal or possible losses of the analyte in stages prior to the measurement. In each kind of calibration, the uncertainty and confidence interval for the determined analyte concentration are given.

A Practical Way to ISO/GUM Measurement Uncertainty for Analytical Assays Including In-House Validation Data

“…Generally, in routine analysis, analytical determinations involve instrumental method where indirect calibration is applied. Common scenarios include external calibration, standard addition calibration (in case of matrix effects) and internal standard calibration (when intrinsic analytical signal variations appear or analyte losses may occur owing to sample preparation procedures [11]).…”