Analysis of emerging pollutants in environmental waters by using photoinduced fluorescence combined with U-PLS/RBL second order multivariate algorithm

HURTADO-SANCHEZ, MARÍA C.; LOZANO, VALERIA A.; RODRÍGUEZ-CÁCERES, MARÍA I.; ESCANDAR, GRACIELA M.; DURÁN-MERÁS, ISABEL

Santiago de Compostela

Congreso; XX Reunión de la Sociedad Española de Química; 2015

Over the past few years, drugs have been considered emerging pollutants due to theircontinuous input and persistence in the aquatic ecosystem even at low concentrations. Theyhave been detected worldwide in environmental matrices, indicating their ineffective removalfrom water and wastewater using conventional treatment methods. For that reason, the numberof analytical methods for their analysis has been increasing in the last decades. Usually, most ofthe analytical methodology employed for the determination of emerging pollutant inenvironmental waters is based on chromatographic separations connected to detection withmass spectrometry (LC-MS) [1], which is a very powerful tool due to their selectivity andsensitivity. However, LC-MS requires a sophisticated and expensive instruments that,unfortunately, are not available in many analytical laboratories. For this reason, in the presentresearch work we propose a novel, quick and easy method based on the acquisition offluorescent signals and their treatment with second-order algorithm. Following this methodology,three emerging pollutants, representative of different groups of therapeutic drugs, wereinvestigated: the anticonvulsant carbamazepine (CBZ), the antibacterial fluoroquinoloneofloxacin (OFL), and the non-steroidal anti-inflammatory piroxicam (PX).CBZ is one of the most frequently detected drugs in environmental waters all over the world,and not present native fluorescence [2]. For that reason, the determination has been carried outby measuring excitation-emission photoinduced fluorescence matrices of the products formedupon ultraviolet light irradiation, in acidic media. In this conditions all target compounds havebeen transformed into fluorescent photoproducts. The selectivity of the method is achievedthrough the use of unfolded partial least squares algorithm (U-PLS). The proposed method wasvalidated in absence and presence of potential interferences. In the last case, the algorithm UPLSwas coupled to the routine RBL to achieve the second order advantage, which permitsquantitating analytes in test mixtures in the presence of interferences which have not beenincluded in the calibration phase. Finally, CBZ, OFL and PX were analysed in real waters from Argentina, including river (Paraná River), underground water (Funes City and Santa Rosa City) and tap water (Venado Tuerto City). They were prepared by spiking them with the analytes at two different concentrations level between 0.08 and 14 ng/mL. The samples were initially filtered to remove the impurities in suspension and, to improve the sensitivity of the proposed method, most samples were subjected to solid-phase extraction (SPE) with C18 disks. The recoveries obtained were comprised between 83-119 %, and the detection limits in preconcentrated real waters samples (1:125) ranged from0.04 to 0.3 ng/mL.References[1] V. Leendert, H. V. Langenhove, K. Demeestere. Trend. Anal. Chem. 67 (2015) 192.[2] V. A. Lozano, G. M. Escandar. Anal. Chim. Acta 782 (2013) 37.