Abstarct: A new simple and sensitive kinetic spectrophotometric method for determination of ascorbic acid is proposed. Method is baxsed on the inhibition effect of ascorbic acid on the sodium bromat-methyl red system in acetic media. The inducton period of reaction is proportional to the ascorbic acid concentraton. The decolorization of methyl red by the reaction products was used to monitor the reaction spectrophotometrically at 514 nm. Under optimum condition ascorbic acid can be determined in the rang of 0.2-3.8 µgml-1 with a 3δ detection limit of 0.1 µgml-1 the relative standard deviation for ten replicate determinations of 1.6,2.6,3.6µgml-1 are 1.55,0.96,2.8 % respectively.this method has been successfully used to the determinastion of ascorbic acid content in tablets and spiked water sample. In this project a simple and sensitive spectrophotometric method for simultaneous determination of copper(II) and cobalt(II) is proposed. Method is baxsed on complex formation of copper(II) and cobalt(II) with 4-(2-pyridylazo)resorcinol. All effective parameters on sensitivity of the method were optimized. Calibration(24 samples) and prediction(10 samples) data sets were prepared by measuring the absorbance of binary mixtures of Cu(II) and Co(II) in the concentration ranges of 0.0-1.6 µgml-1 and 0.1-2.2µgml-1 for Cu(II) and Co(II) respectively. The results obtained by applying PLS method baxsed on the SVD was used for multivariate modeling MCR approach was used for preprocessing of absorbance data. The obtained results by applying PLS with and without MCR were statistically compared. The 3δ detection limits were 0.0318 and 0.050 for copper(II) and cobalt(II) respectively. The relative standard deviations for six replicate determinations of 1.3 and 1.0 µgml-1copper(II) and cobalt(II) were 1.83and 1.86 respectively. The method has been applied to the simultaneous determination of copper(II) and cobalt(II) in alloy and tap water sample with satisfactory results. (Recovery 100.4 -103.0% for copper(II) and 96.0-106.4% for cobalt(II)).