Simultaneous determination of naproxen, salicylic acid and acetylsalicylicacid by spectrofluorimetry using partial least-squares (PLS) multivariate calibration

Determination of naproxen, salicylic acid and acetylsalicylic acid has been carried out in mixtures of up to three components by recording emission fl uorescence spectra between 300 and 520 nm with an excitation wavelength of 290 nm. The excitation-emission spectra of these compounds are strongly ove rlapped, which does not permit their direct determination without previous separation by conventional methodologies. Here, a method is proposed for th e determination of these chemicals by the use of a full-spectrum multivaria te calibration method, partial least-squares (PLS). The experimental calibr ation matrix was designed with 18 samples. The concentrations were varied b etween 0.1 and 1.0 mu g ml(-1) for naproxen, 0.5 and 5.0 mu g ml(-1) for sa licylic acid and from 2.0 to 12.0 mu g ml(-1) for acetylsalicylic acid. The cross-validation method was used to select the number of factors. To check the accuracy of the proposed method, the optimized model, obtained using P LS-I, was applied to the determination of these compounds in pharmaceutical s and human serum samples previously spiked with different amounts of each chemical. (C) 1999 Elsevier Science B.V. All rights reserved.