Experimental studies of uncertainties associated with chromatographic techniques

The paper describes experiments for the evaluation of uncertainties associa ted with a number of chromatographic parameters. Studies of the analysis of vitamins by HPLC illustrate the estimation of the uncertainties associated with experimental "input" parameters such as the detector wavelength, colu mn temperature and mobile phase flow-rate. Experimental design techniques, which allow the efficient study a number of parameters simultaneously, are described. Multiple linear regression was used to fit response surfaces to the data. The resulting equations were used in the estimation of the uncert ainties. Three approaches to uncertainty calculation were compared - Kragte n's spreadsheet, symmetric spreadsheet and algebraic differentiation. In ca ses where non-linearity in the model was significant, agreement between the uncertainty estimates was poor as the spreadsheet approaches do not includ e second-order uncertainty terms. (C) 2001 LGC (Teddington) Ltd. Published by Elsevier Science B.V. All rights reserved.