Abstract: The multicomponent spectrophotometric determination of the organic mixture system containing phenolic compounds was investigated.For these ill-conditioned systems with very similar spectral characteristics, both ordinary least squares regression and Kalman Filtering methods are not able to give satisfactory results.We used the ridge regression method newly developed in statistical literature to treat these ill-conditioned systems.The results obtained are evidently superior to those obtained by ordinary least squares or Kalman methods.

Key words: Ridge regression, Ill-conditioned analytical system, Chemometrics, Biased estimation, Multicomponent spectrophotometric Determination