The Essential Performance Characteristic of Calibration

The method s standard deviation (DIN 32645, DIN 38402 T51) represents the key parameter of performance. It is calculated by dividing the residual standard deviation by the sensitivity of the method and it essentially determines the maximum precision for evaluation of analytical results. The standard deviation of a method provides the scale to estimate the accuracy of a method early on the basis of its calibration characteristics. 

Due to the software that is widely available for evaluating calibration characteristics, calibration formulas are not explicitly written out here. Instead, we refer to plots of the calibration function and especially of the residuals, which provide a suitable basis for discussion by transparently showing the expected range of possible but still reliable results. More so than the confidence range of the calibration fimction, the prediction interval enables an evaluation of the precision and trueness. For this reason, we included the prediction limits in the residuals plot in a manner first published in Ref. [1]. 

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