Direct photolysis of benzoylecgonine under UV irradiation at 254nm in a continuous flow microcapillary array photoreactor

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2016-01, Vol.283, p.243-250
• Main Authors: Russo, Danilo, Spasiano, Danilo, Vaccaro, Marianna, Andreozzi, Roberto, Li Puma, Gianluca, Reis, Nuno M., Marotta, Raffaele
• Format: Article
• Language: English
• Subjects: Benzoylecgonine; Caffeine; Cocaine metabolite; Direct photolysis; Microcapillary film; Photoreactor
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2015.07.061

•Use of an innovative microcapillary film array photoreactor.•Microfluidics approach for studying the photochemical behavior of illicit drugs.•Estimation of the quantum yield photolysis of benzoylecgonine, a cocaine metabolite.•Estimation of the quantum yield photolysis at 254nm of caffeine. Benzoylecgonine (BE) is the major metabolite of cocaine and a contaminant of emerging concern often detected in sewage treatment plant (STP) effluents and surface waters. In this study, an innovative microcapillary film (MCF) array photoreactor made of fluoropolymer material was used to determine the direct photolysis quantum yield at 254nm of benzoylecgonine. The photolysis quantum yield of BE was found to be (6.22±0.19)⋅10−3molein−1. The proposed methodology was validated by estimating the quantum yield of caffeine (7.48±0.64)⋅10−4molein−1, which was found in agreement with results published in literature. The MCF uses a very small sample volume (in the order of 330μL per meter length of material) and allows extremely rapid photolysis with a short contact time ranging from a fraction of seconds to few minutes. The novel microfluidic-based approach presented in this study is particularly useful for determining the photochemical behavior of highly priced pharmaceuticals, illicit drugs, metabolites and uncommon or regulated substances.