MULTICOMPONENT DETERMINATION OF CHLORINATED HYDROCARBONS USING A REACTION-BASED CHEMICAL SENSOR .2. CHEMICAL SPECIATION USING MULTIVARIATE CURVE RESOLUTION

A new multivariate curve resolution method that can extract analytical information from UV/visible spectroscopic data collected from a react ion-based chemical sensor is proposed. The method is demonstrated with the determination of mixtures of chlorinated hydrocarbons by estimati ng the kinetic and spectral profiles of the chemical species formed in the Fujiwara reaction. The three key aspects of the proposed method a re (1) the initial estimation of the kinetic concentration profiles fr om evolving factor analysis; (2) the implementation of an alternating and constrained least squares method to optimize the determination of both the spectral and concentration profiles of the species present in the reaction, and (3) the development of a quantitative approach base d on the simultaneous analysis of standards and unknowns for the deter mination of the initial concentration of the analytes in the mixtures.