title: Two different strategies for the fluorimetric determination of piroxicam in serum.
abstract: Two different spectrofluorimetric methods for the determination of piroxicam (PX) in serum are presented and discussed. One of them is based on the use of three-way fluorescence data and multivariate calibration performed with parallel factor analysis (PARAFAC) and self-weighted alternating trilinear decomposition (SWATLD). This methodology exploits the so-called second-order advantage of the three-way data, allowing to obtain the concentration of the studied analyte in the presence of any number of uncalibrated (serum) components. The method was developed following two different procedures: internal standard addition and external calibration with standard solutions, which were compared and discussed. The second approach investigated is based on the combination of solid-phase extraction (SPE) and room temperature fluorimetry. Both methods here presented yield satisfactory results. The concentration range in which PX could be determined in serum was 1-10 microg ml(-1). The limits of quantification for the experimental solutions using the chemometric approach were 0.09 microg ml(-1) for the standard addition mode and 0.12 microg ml(-1) using external calibration (both for PARAFAC and SWATLD algorithms). In the solid-surface fluorimetric method, the calibration graph was linear up to 0.22 microg ml(-1) and the limit of quantification was 0.02 microg ml(-1).
authors.affiliation: Departamento de Quimica Analitica, Facultad de Ciencias Bioquimicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, Rosario, Argentina.
authors.forename: J A
authors.initials: JA
authors.lastname: Arancibia
authors.forename: G M
authors.initials: GM
authors.lastname: Escandar