Application of thymine-based copolymers in the quantification of organic pollutants in water by sensitized fluorescence

Abstract

Bio-inspired copolymers based on thymine can interact with certain organic molecules and therefore they can be used as organized media or as optical sensors for analytical determinations. Particularly, the thymine-based copolymers have a high affinity for benzo(a)pyrene (BaP) and pyrene (Pyr), two main persistent organic pollutants in water. In the present work, such interaction is applied for the development of a simple analytical method based on fluorescence enhancement of BaP and Pyr. Since BaP and Pyr fluorescence spectra are strongly overlapped, a multivariate analysis of the data is proposed. The selectivity of the method was achieved through a parallel factors analysis (PARAFAC) of excitation-emission fluorescence matrices. The method performance was tested by simultaneous determination of BaP and Pyr in water samples, without pre-concentration steps or full chromatographic resolution. Studies of recovery for both analytes added to tap and surface waters were done, obtaining results in the order of 87–115%. The analysis was performed in the presence of additional species whose signals overlap with those of the analytes. In all cases, the calculated analytical figures of merit were compared with those obtained by the reference chromatographic method. In addition, a comparison of our method with the reference one is made based on the calculation of their respective eco-scales. The quality of the achieved results indicates that a second-order advantage was reached, while our method represents a greener alternative than the reference chromatographic methodology.