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Graphene oxidemeasurementspHSensor


New sensor capable of accurate pH measurements. The aim of the invention is to provide a sensor capable of accurately monitoring pH and its variations over time, which is sufficiently cheap to be used for a limited period of time and then discarded; interfaced to a reading system allows the acquisition of data even automatically and / or remotely; versatile for use in different environments and applications. The sensor was used to measure the pH of liquids and exudate samples from a patient with a venous ulcer.

Technical features

The most used pH measuring systems consist of glass membrane electrodes, which make the potential difference measurement, that is established on the two surfaces of a membrane; this type of electrode is robust, versatile and precise, but it cannot be miniaturized nor be considered a disposable device. For less precise but rapid measurements, we resort to the use of “litmus papers”, which need to be read by an operator, and can give inaccurate readings when used with solutions. The purpose of the invention is to provide a sensor that solves the above mentioned technical drawbacks. It is a potentiometric sensor coated with graphene oxide.

The sensor was printed in PET and tested in complex matrices e.g. measurements on plasma and on the port waters of Livorno for 3 weeks. The measurements obtained were superimposable to those detected by a commercial pH meter with the advantages due to the versatility and automaticity of the proposed system. The sensor can be functionalized thanks to the use of enzymes to perform specific detections, e.g. urea.

Possible Applications

  • Environmental sector (waste and water characterization);
  • Industrial processes (preparation of chemical baths for painting and plating);
  • Quality control sector (fermentation processes, cosmetics);
  • Medical field (chronic wounds, gastric juices);
  • Sports field.


  • Not fragile;
  • No need for frequent calibration;
  • Biocompatible materials;
  • Economical and versatile;
  • Automatic.