Calculation of the Detection and Determination Limits of Volumetric Methods

Abstrakt

A procedure for calculation of the detection and determination limits of volumetric methods is presented. The calculation is demonstrated on the argentometric determination of chlorides according to Mohr. The procedure is based on recognition of all important steps of the method and their characterization by uncertainties represented by the standard deviations: uncertainty of burette and uncertainty of the volumetric determination. The latter was calculated from a linear regression of the measured volumes vs. concentrations of chlorides. The overall uncertainty was calculated by the method of error propagation. The detection limit was calculated at 0.9 mg.l^-1 and the determination limit at 3.0 mg.l^-1 chlorides.