Non-linear calibration in single point flow titration of protolytes - A comparison of model options by using Delta Test

The complete description of the non-linear absorbance/concentration relatio nship obtained for systems used in single point photometric flow injection titrations of acids and bases is presented. The applicability of different models for fitting calibration data, as well as the more frequently used da ta processing options, are investigated under normal and restraining condit ions by using experimental and simulated data sets. Theoretical and empiric al models are examined in order to choose the simplest and the more efficie nt ones to provide good recoveries. The comparison among models is based on a novel statistical criterion (Delta Test) for contrasting the prediction efficiency by detecting systematic errors in estimated concentrations. (C) 2000 Elsevier Science B.V. All rights reserved.