Optimisation using a surface response methodology of a system with drift: Application to a flow analysis system with electrochemical detection

摘要: The aim of this work is to optimise the multivariate signal obtained by means a continuous flow system with electrochemical detection when three phenolic compounds (2,4-dimethylphenol, phenol and 4-nitrophenol) are analysed. Firstly, an experiment carried out according central composite design for factors percentage methanol pH carrier solution, taking as response net analyte (NAS) each analyte. analysis has drift that be taken into account optimising analytical signal. To do so, between two individual experiments, reference inserted in experimental conditions corresponding centre design. This allows one directly correct linear correction factor variation NAS previous sample subsequent one. However, detailed data suggests interaction analysis, which confirmed second experiment. As consequence, correcting voltammograms subtracting contribution principal component related proposed, separately analytes blank solutions, next estimating NAS. Using corrected design, significant quadratic models high explained variance studied compound obtained. In addition, optimum found common desired all analysed using desirability function, being at 1.8% 5.9.