MULTICOMPONENT DETERMINATION OF CHLORINATED HYDROCARBONS USING A REACTION-BASED CHEMICAL SENSOR .1. MULTIVARIATE CALIBRATION OF FUJIWARA REACTION-PRODUCTS

Multicomponent analysis for 1,1,1-trichloroethane, trichloroethylene, and chloroform is demonstrated by partial least squares modeling of ab sorbance data collected from the Fujiwara reaction of these analytes o ver time. Optimal calibration times are determined for each analyte de pendent upon its reaction rate. This is the simplest example of trying to use the selectivity gained from a second data dimension or order. Problems associated with first-order calibration are demonstrated when interferences unaccounted for in the calibration model are present. D etermination of 1,1,1-trichloroethane in the presence of the other two species is also demonstrated using the generalized rank annihilation method and trilinear decomposition for second-order calibration. A sub sequent paper describes an approach using multivariate curve resolutio n to extract the analytical information from the spectral and temporal profiles of analytes in the Fujiwara reaction.