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Download fileOpen-Source Portable Device for the Determination of Fluoride in Drinking Water
journal contribution
posted on 2021-01-08, 10:29 authored by Eugenio H. Otal, Manuela Leticia Kim, Steffen Dietrich, Ryogo Takada, Shinji Nakaya, Mutsumi KimuraThe
prolonged exposure to fluorides results in the development
of several diseases, from dental fluorosis to crippling deformities
of the spine and major joints. The population exposed to high fluoride
concentration is located in developing countries where the assurance
of water quality is difficult to perform. Addressing this challenge,
an open-source system for the determination of fluoride in natural
water was developed using the equilibrium between the red Fe–SCN
complex and the colorless Fe–F. The reaction develops in cotton
substrates to reduce the manipulation of liquid reagents and reduce
the errors by nontrained operators. The system was optimized by image
analysis and implemented in an open-source Arduino-based device and
data was acquired through the serial port of a cell phone, which is
also used as a power source, avoiding the use of a battery and reducing
production costs. The device showed a detection limit of 0.7 mg L–1 and a linear range of up to 8 mg L–1. This extended detection limit makes the device useful for the application
in regions where the fluoride concentration in drinking water is far
higher than the United Nations limit (1.5 mg L–1), e.g., the United Republic of Tanzania, where the upper limit of
F– was extended to 4 mg L–1 or
in USA, where the Environmental Protection Agency established the
Maximum Contaminant Level of F– in drinking water
at 4 mg L–1. The method was tested with natural
waters from the Arusha region in the northeast of Tanzania and validated
against the results from ion chromatography showing a good correlation.
The developed device exhibits chemical stability of 5 days, allowing
it to be manufactured and distributed in local areas and, also, modified
according to the requirements of the water composition due to Industry
4.0 concepts used in the design.