Simultaneous voltammetric temperature and humidity sensor

Electrochemical sensors for the detection of gases are inherently attractive due to their high sensitivity and low cost. All electrochemical sensors depend on an electron transfer step, the rate of which is influenced by the local environment. Temperature and humidity are important environmental factors that affect this rate. It is important to monitor changes in temperature and humidity, as they can indirectly influence the measurement of other properties such as the quantification of chemical species.

Oxford researchers have developed an electrochemical oxygen sensor with a built-in voltammetric thermometer, removing the need for thermostated operating conditions. This system will allow more accurate gas sensing over a range of temperatures potentially increasing the commercial applicability of electrochemical sensors. Furthermore, the researchers have developed a method for the direct detection of temperature and humidity at the electrode solution interface. This method is suitable for integration with other voltammetric sensing methods and analytical probes.

Highly sensitive and low-cost electrochemical sensing

Electrochemical or Amperometric sensing of analytes is a growing field with technologies now available for the detection of a range of dissolved gases (CO2, O2, H2S, NOx, SOx). In addition, these sensors have found applications in medicine, with the development of disposable glucose sensors for diabetics. All electrochemical sensors operate using the same principle, which involves an electron transfer event from the dissolved analyte to an electrode, driven by an applied potential. The current that is generated from this electron transfer gives the desired analytical signal. In general, the electrochemical detection methodology is appealing to consumers as it
is highly sensitive and relatively low cost.

Current limitations

One of the disadvantages of current electrochemical sensors include the dependence of the electron transfer step on the local environment. Important factors influencing the sensitivity of the technique include changes in the temperature and humidity. This leads to a requirement for close monitoring and in some cases strict regulation of the operating temperature, adding a degree of complexity and increased the cost to the device. In the limited number of cases where these crucial parameters are monitored, it is typically performed in a device separate from the electrodes monitoring the redox reactions of interest. It is therefore desirable to have an integrated device which can monitor changes in temperature and humidity throughout the operation.

Electrochemical temperature and humidity sensor

Oxford researchers have developed a device, which combines a voltammetric thermometer and an amperometric gas sensor. This technology can provide precise data concerning dissolved gas concentrations and operating temperature simultaneously, thus removing the need for external temperature monitoring and regulation.

Furthermore, the researchers have developed a method for simultaneous temperature and humidity sensing which is suitable for integration into electrochemical sensors and analytical probes.

The key advantages of this technology include:

  • High sensitivity
  • Relatively low cost
  • Simple device architecture
  • No requirement for external temperature and humidity monitoring

This technology could be used to create more robust sensors capable of operating accurately over a wide range of environmental conditions.

Patent protection

This technology is the subject of two patent applications. Oxford University Innovation is seeking external partners who wish to explore the use of this technology for commercial applications.

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