Chemometrics-assisted photoinduced fluorimetry for the determination of the antiepileptic carbamazepine in environmental waters

LOZANO, VALERIA A.; ESCANDAR, GRACIELA M.

Budapest

Congreso; XIII Chemometric in Analytical Chemistry; 2012

A new photochemically-induced fluorescence system combined with second-order chemometric analysis for the determination of the anticonvulsant carbamazepine (CBZ) is presented. CBZ is a widely used drug for the treatment of epilepsy and psychiatric diseases, and is included in the group of emerging contaminant present in the aquatic environment [1]. This pharmaceutical pollutant is of particular concern because of its important health effect at low concentrations [2]. CBZ is not fluorescent in solution but can be converted into a fluorescent compound through a photochemical reaction in concentrated hydrochloric acid. The determination is carried out by measuring excitation-emission fluorescence matrices of the photoproduct formed upon ultraviolet light irradiation in a laboratory-constructed reactor constituted by two simple 4 W germicidal tubes. Experimental conditions related with both the reaction medium and the geometry of the photoreactor are optimized. The developed approach enabled the determination of CBZ at trace levels without the necessity of applying separation steps, and in the presence of uncalibrated interferences (e.g., other pharmaceuticals such as piroxicam, ibuprofen, salycilate, diclofenac and salbutamol) which display photoinduced fluorescence and may be potentially present in the investigated samples. Thus, algorithms which achieve the second-order advantage are applied, namely parallel factor analysis (PARAFAC), unfolded partial least-squares coupled to residual bilinearization (U-PLS/RBL), and multivariate curve resolution-alternating least squares (MCR-ALS). The study is employed for the discussion of the scopes and yields of each applied second-order chemometric tools.            An approach for the determination of CBZ and its main metabolite (10,11-epoxide CBZ), which also possesses pharmacological activity, is suggested. The quality of the proposed method is probed through the determination of the studied emerging pollutant in both environmental and drinking water samples.  Acknowledgement: The authors gratefully acknowledge the Universidad Nacional de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas (Project PIP 1950) and Agencia Nacional de Promoción Científica y Tecnológica (Project 2010?0084) for financially supporting this work.            References: [1] S.D. Richardson, T.A. Ternes, Anal. Chem., 83, 4614 (2011). [2] M. Schriks, M.B. Heringa, M.M.E. van der Kooi, P. de Voogt, A. van Wezel, Water Res., 44, 461 (2010).