Monitoring of Volatile Organic Compounds (VOCs) is required for a number of gas analysis applications, such as:
- Indoor Air Quality (IAQ)
- Industrial Fugitive Emissions
- HazMat Events
- Environmental Pollution
VOC analyzers for those applications are typically based on the Photoionization Detector (PID) principle, which allows for a quick, portable and inexpensive measurement of total VOCs. A number of commercial PID-based instrument are available on the market now (RAE Systems, PhotoVac and others). They are relatively portable (hand – held), comparatively inexpensive ($1000 to $4000) and low-maintenance instruments.
For a number of applications it is required to simultaneously monitor other gases besides VOCs: e.g. CO, O2, H2S, etc. All those gases can be measured by a set of small, inexpensive electrochemical or catalytic sensors that may be combined in a portable, “multi-gas” instrument.
Photoionization detectors, however, due to their relative complexity, could not be built in the form factor of electrochemical sensor - until now. Therefore, for VOC measurement, a separate PID instrument was required, which adds to complexity, bulk and the cost of monitoring. Development of a PID “plug-in” sensor would result in the possibility of a “total analytical solution” in one portable package. Availability of a subminiature PID sensor would also help to address applications, where the small size and low power consumption are critical requirements. Use of hi-tech materials, electronics and technologies would not only help to miniaturize the instrument, but also to reduce the cost and make it a true mass-production device, which would help to expand the application tremendously and penetrate such markets as the Residential Indoor Air Quality monitoring.
2. Project’s Scope
The goal of this project was to develop a miniature, standalone PID sensor in the form factor of an electrochemical sensor (City Technologies 4P Series). The PID sensor must be compatible – geometrically and electrically - with portable multisensor instruments, existing on the market. Another objective was for the sensor to be competitive performance wise with other PIDs on the market.