General equation for determining the dissociation constants of polyprotic acids and bases from additive properties Part III. Calculation of errors

A weighted least squares method is used to calculate the dissociation constants of polyprotic acids and bases from measurement of additive properties, and to evaluate the effect of the errors of measurement on these constants. The method is based on the theory of statistical adjustment of data, which was originally described in detail by Deming [W.E. Deming, Statistical Adjustment of Data, Wiley, London, 1943]. The advantage of the theory is that it makes the propagation of errors of measurements of all variables explicit and easy to analyze. The theory is presented in this paper in a general form by adapting the formalism of Wentworth [W.E. Wentworth, J. Chem. Educ. 42 (1965) 96], and then applied to the measurements of additive properties. Illustrative examples from spectrophotometry and reversed-phase high-performance liquid chromatography are presented. (C) 2000 Elsevier Science B.V. All rights reserved.