SmartFluo goes FDOM: Advancement of the DIY fluorometer approach towards UV excitation

Water quality environmental parameters in the highly sensible and varying coastal regions concern societal relevant sectors such as aquaculture, fishing and tourism. Therefore, proper water quality and consequentially regular monitoring covering large spatial areas is of interest not only for scientist but also for stakeholders and citizens. So far insufficiently sampled water quality parameters, requiring cost intensive laboratory analysis, can be addressed through measuring inherent optical properties as a proxy. A more sufficient and distributed monitoring can be achieved through the involvement of citizens enabling a "Citizens' observatory for coast and ocean optical monitoring" (CITCLOPS; European Union funded project). Implementing low-cost tools based on mobile-devices for measuring water quality parameters such as fluorescence compounds of colored dissolved organic matter (FDOM) is targeted to encourage and involve citizens. Quinine-sulfate dilution series, a FDOM related water constituent, was investigated with a do-it-yourself (DIY) fluorometer connected to the smartphone while performance was controlled by a benchtop luminescence spectrometer. This approach delivered a high coefficient of determination (R-2 = 0.99), therefore providing a novel extension of recently developed low-cost tools for monitoring water quality.