Acronym : CFph

Project’s leader (in FEMTO-ST) : B.Gauthier-Manuel

Partnership : Satt-Sayens and  FEMTO-ST

Abstract :

Liquid pH measurement is of considerable importance in many areas.
In addition to the medical field (pharma/biotech) for which pH changes in body fluids may be the cause (or consequence) of a malfunction, the main areas in which accurate pH measurement is crucial are the agri-food industry, the chemical industry and the environment. This measure is a marker of the state of the media studied in terms of quality control, process control, monitoring of certain properties, detection of contamination to name a few. The classic technique is to use a potentiometric method (glass electrode) which requires the simultaneous use of a reference electrode and requires periodic calibration. A Ion Selective Field Effect Transistor (ISFET). It is a A field effect transistor whose gate pin, in silicon nitride, aluminium oxide or tantalum, is sensitive to changes in H+ ion concentration. This technology also requires a reference electrode. It is currently in sharp decline due to aging of the reference electrode too expensive to replace. We propose in this project the realization of an industrializable prototype of measurement of original pH without optical calibration. This method pattented, is based on the measurement of the variation of the fluorescence spectrum of grafted molecules at the end of a fiber optic as a function of pH. A mathematical method using all the points of the fluorescence spectrum and not only its maximum intensity allows the measurement of the pH seen by these molecules without resorting to prior calibration. Given the size of the sensor (200µm optical fiber) it will be possible to measure the pH in small volumes of about ten nano liters.

Funding agency : SATT-Sayens

Grant or funding obtained : 260 k€

Start and end dates : 02/2020 – 02/2022