PARAFAC and PLS applied to spectrophotometric determination of tetracycline in pharmaceutical formulation and biological fluids

A simple and rapid analytical procedure was proposed for determination of tetracycline in pharmaceutical formulation, urine and plasma based on chemometrics methods and spectrophotometric measurements. The calibration set was constructed with twenty solutions in concentration range 0.25-13.00 mu g ml(-1) for tetracycline. The procedure was repeated at nine different pH values. Partial least squares (PLS) models were built at each pH and used to determinate a set of synthetic tetracycline solutions. The best model was obtained at pH 8.00 (PLS-PH8). Parallel factor analysis (PARAFAC) model was applied to a three-way array constructed using all the pH data sets and enabled better results. The capabilities of the method for the analysis of real samples were evaluated by determination of tetracycline in pharmaceutical formulations and biological fluids with satisfactory results.