The two stereo-isomers; quinine and quinidine have been determined in their mixtures in the IR region using chemometric multivariate methods, principal component regression ( PCR) and partial least squares (PLS). A training set of thirty synthetic binary mixture solutions in the possible combinations containing 0.0-4.0 and 4.0-0.0% w/v quinine and quinidine, respectively in chloroform was used to develop the multivariate calibrations. A validation set containing thirty synthetic binary mixtures

more »

... of variable ratios in the range of 0.2-4.0 and 4.0-0.2% w/v for quinine and quinidine, respectively in chloroform was used to validate the developed calibrations. The results of analysis of the validation synthetic mixtures were found to be 100.5؎0.44% (R.S.D.%‫)44.0؍‬ and 100.5؎0.38% (R.S.D.%‫)83.0؍‬ for quinine and 100.1؎0.67% (R.S.D.%‫)76.0؍‬ and 100.1؎0.68% (R.S.D.%‫)86.0؍‬ for quinidine using PCR and PLS models, respectively.