Flow injection and multivariate calibration techniques for process analysis
The role of process analytical chemistry is summarised in chapter one with particular emphasis on a multidisciplinary approach and the instrumental requirements for on-plant analysis. These concepts are extended to process FIA, highlighting its potential for simultaneous multicomponent determinations. The development of an automated FIA monitor for the on-line determination of sulphite in potassium chloride brine is covered in the second chapter. Reaction stability is demonstrated and the results of on-plant validation and on-line trials are presented. The next chapter deals with the concepts of multivariate calibration. Direct multicomponent analysis, principal components regression and partial least squares regression are critically examined in practical spectroscopic terms and statistical terms. The relative predictive abilities of these techniques are compared in chapter four for the resolution of a multicomponent UV-visible spectrophotometric data set. Chapter five describes the development of an automated FIA-diode array system for the simultaneous determination of phosphate and chlorine. The implications of combining reaction chemistries and the influence of a number of calibration parameters are considered in detail. Finally, the jackknife is presented as a means of dimensionality estimation' and bias correction in PLS modelling. Data sets from the literature are analysed and the results compared with those obtaining using commercial software.