Preconcentration and flow-injection multivariate determination of priority pollutant chlorophenols

A combined flow-injection analysis and multivariate calibration method is developed for the simultaneous determination of priority pollutant chlorophenols (2-chlorophenol, 4-chloro-3-methylphenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol and pentachlorophenol) in water. Chlorophenols were preconcentrated in an XAD-4 adsorbent resin. The ion pairs formed with tetrabutylammonium at pH 9.1 were extracted in chloroform and detected in a diode-array spectrophotometer in the wavelength range 200–430 nm. Three multivariate calibration methods, classical least squares (CLS), Kalman filter and partial least squares were used for comparative purposes. Comparison of the standard error of prediction shows significant differences for the determination of 2,4,6-trichlorophenol only, the best results being obtained by the CLS method.