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 absorbance data collected from the Fujiwara reaction of these analytes over time. Optimal calibration times are determined for each analyte dependent 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. Determination 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 subsequent paper describes an approach using multivariate curve resolution to extract the analytical information from the spectral and temporal profiles of analytes in the Fujiwara reaction.