Ph control for analyte detection

A sensor device, comprising:

• a substrate,
• a flow path defined on the substrate adapted to receive a liquid;
• a set of electrodes, wherein the set of electrodes comprises:
• a pair of pH generation electrodes, wherein the pair of pH generation electrodes include a pH generation working electrode and a pH generation counter electrode;
• a reference electrode;
• and
• a pH sensing electrode;
• a controller;
• and
• a detection electrode placed, as part of said set of electrodes, between the pH generation electrodes, such as to be subjected to a change in pH of said portion of the liquid, as caused by the pH generation electrodes, said detection electrode being otherwise able to produce, together with the reference electrode, a signal indicative of the presence of chemical species in said liquid portion,
• wherein:
• the set of electrodes is arranged along the flow path, the pH sensing electrode arranged so as to be subjected to a change in pH of a portion of the liquid on the flow path;
• and
• the controller is configured to apply a voltage across said pH generation electrodes based on a signal obtained via the pH sensing electrode and the reference electrode, so as modify a pH of the liquid at the pH generation working electrode and the pH generation counter electrode;
• and
• the controller is further configured to receive a signal obtained via the detection electrode and the reference electrode to detect said chemical species.