Photo Ionization Detection (PID)
| Category |
Chemical |
| Type |
Analytical |
| Ease of Use |
 |
| Determination Capability |
 |
How it works
PIDs are used to determine the presence of chemicals that can be ionized when subjected to a UV source. This detector is commonly used to detect organic chemicals in air since most organics have some ionization potential (IP) by UV. Different UV lamps are available from 11.7eV to 10.2eV. The higher energy UV can detect most organic chemicals while the lower energy lamps are more selective to organics with double bonds and aromatic rings like Toluene. PIDs do not separate chemicals, therefore they are typically used as an initial screening tool to determine if any organic chemicals are present in the air.
Limitations
The challenges for PIDs are that they can’t differentiate between hazardous and non-hazardous organic vapors and the user must ensure they chose the correct lamp to make sure they can detect the chemicals of concern.