title: SmartFluo: A Method and Affordable Adapter to Measure Chlorophyll a Fluorescence with Smartphones.
abstract: In order to increase the monitoring capabilities of inland and coastal waters, there is a need for new, affordable, sensitive and mobile instruments that could be operated semi-automatically in the field. This paper presents a prototype device to measure chlorophyllafluorescence: the SmartFluo. The device is a combination of a smartphone offering an intuitive operation interface and an adapter implying a cuvette holder, as well as a suitable illumination source. SmartFluo is based on stimulated fluorescence of water constituents such as chlorophylla. The red band of the digital smartphone camera is sensitive enough to detect quantitatively the characteristic red fluorescence emission. The adapter contains a light source, a strong light emitting diode and additional filters to enhance the signal-to-noise ratio and to suppress the impact of scattering. A novel algorithm utilizing the red band of the camera is provided. Laboratory experiments of the SmartFluo show a linear correlation (R 2 = 0.98) to the chlorophyllaconcentrations measured by reference instruments, such as a high-performance benchtop laboratory fluorometer (LS 55, PerkinElmer).
authors.affiliation: Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University Oldenburg, Schleusenstrasse 1, 26382 Wilhelmshaven, Germany. anna.friedrichs@uol.de.
authors.forename: Anna
authors.initials: A
authors.lastname: Friedrichs
authors.affiliation: Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University Oldenburg, Schleusenstrasse 1, 26382 Wilhelmshaven, Germany. jbusch@mpi-bremen.de.|Life Sciences and Chemistry, Jacobs University, Campus Ring 1, 28759 Bremen, Germany. jbusch@mpi-bremen.de.
authors.forename: Julia Anke
authors.initials: JA
authors.lastname: Busch
authors.affiliation: Institute for Environmental Studies, VU University Amsterdam, De Boelelaan 1087, 1081 HV Amsterdam, The Netherlands. h.j.vander.woerd@vu.nl.
authors.forename: Hendrik Jan
authors.initials: HJ
authors.lastname: van der Woerd
authors.affiliation: Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University Oldenburg, Schleusenstrasse 1, 26382 Wilhelmshaven, Germany. oliver.zielinski@uol.de.
authors.forename: Oliver
authors.initials: O
authors.lastname: Zielinski
keywords: 3D printing; LED; affordable sensors; citizen science; marine environment; open laboratory ware