Advances in Photometric Fluoride Measurements in Effluent Fuel Cell Water

The increasing focus on per- and polyfluoroalkyl substances (PFAS) by regulatory bodies, such as the EU's plan to ban PFAS products [1], has brought the topic into the public view. It is therefore important to have a reliable and suitable measurement method for the detection of fluoride in effluent fuel cell water.
This study is an improvement of the method from our previous work, in which we demonstrated an approach to detect fluoride in effluent fuel cell water, using a photometer [2].
Here we demonstrate, that by varying the reagent (SPADNS2) concentration, an increase in detection range or an improved sensitivity is possible. direct correlation between the reagent amount, detection sensitivity and linear range is measureable.
Through the variation of the reagent concentration, a direct correlation between the reagent amount, detection sensitivity and linear range is measureable. For a total sample volume of 1000 µL, varying the reagent amount between 50 and 200 µL changes the linear range to 0.5 mg L-1 and 5 mg L-1 respectively. This adjustment also has an impact on the sensitivity of the method, a reagent amount of 50 µL shows a 10-fold greater sensitivity (1.99 intensity / concentration) compared to 200 µL, where it is reduced to 0.20.
We have demonstrated the versatility of the photometric method in terms of adaptability for different concentration ranges. By adjusting the reagent amount to specific concentrations, and through the ability to readily change calibrations on the system, the method becomes suitable for a broader range of measurements.

This research is performed under the HyLife project (K-Project HyTechonomy, FFG grant number 882510) which is supported by the Austrian Research Promotion Agency (FFG).
[1] European Chemicals Agency, ECHA, 22/03/2023
[2] M. Heidinger, E. Kuhnert, K. Mayer, D. Sandu, V. Hacker, and M. Bodner, “Photometric Method to Determine Membrane Degradation in Polymer Electrolyte Fuel Cells,” Energies 2023, Vol. 16, Page 1957, vol. 16, no. 4, p. 1957, Feb. 2023, doi: 10.3390/EN16041957.