Pressure Resistant pH Meter

A novel device for measurement of pH over a wide range of pressures and in electrically noisy environments

The Need

A pH Meter is an electrical device that is used to measure the concentration of hydrogen ions in a given solution. This solution is often liquid, but can also be used to measure the pH of semi-solid substances. The resulting data indicates whether the solution is acidic or basic, but this discovery is under the limitation of being performed under a subdued environment. Products currently on the market are able to deliver accurate readings under this pretense, but without it they often deliver faulty and unreliable readings. Alternative methods call for constant attention from the user to maintain a controlled environment to prevent chemicals from contaminating the process and therefore the results. An inefficiency like this in the process raises questions about how to sustain consistent readings for situations where the environment is less than ideal. This hole in the market has created an opportunity for a product that is capable of producing equal or greater results in situations that previously had a wider range of outcomes.

The Technology

Researchers at The Ohio State University, led by Dr. Sudhir Sastry, developed a device that delivers improved pH sensitivity at extreme pressures and optimizes the increasingly valuable high pressure pasteurization processes (HPP). The pH of a system is determined using electrical conductivity measurements across a selectively-permeable membrane allowing only the passage of hydrogen ions. This type of sensing, which allows variable voltage in its input, has many advantages over traditional products when applied to industrial processes requiring harsh conditions. The resulting output will then give the user more accurate readings by optimizing the signal intensity. To date, this device has been developed, constructed and tested as a prototype with successful results.

Commercial Applications

  • pH measurement systems
  • Food science
  • High pressure processing (HPP) of food or biomaterials
  • Agriculture sensors


  • pH sensing during high pressure processing can inactivate microorganisms in foods and biomaterials at low temperatures and improve production quality and throughput
  • Variable voltage input allows for optimization of output signal intensity for more accurate readings

Loading icon