Photoionization detectors are light, portable instruments that are invaluable for assessing potential chemical hazards onsite.
Most chemical analysis is conducted in a laboratory setting. Forensic samples from a crime scene are sent “to the lab.” Urine samples from Olympic athletes are sent “to the lab.” Even soil samples from a homeowner’s backyard that might have a leaky underground oil tank are generally sent “to the lab” for evaluation. In many cases, this is the most practical system since analytical instruments tend to be large, expensive, and sensitive to the bumps and jolts associated with travel. However, when hazards need to be evaluated swiftly or when air and gas samples need to be analyzed another approach is needed. Photoionization detectors (PIDs) are a way of taking the chemistry laboratory to the samples.
PIDs can detect organic gases and vapors, and are small enough and rugged enough to be portable. Best of all, they provide data almost immediately. They are commonly used to determine indoor air quality, to measure the vapors of accelerants in arson investigations, and in ensuring safe handling of hazardous materials. They have been a particularly valuable tool in assessing environmental contamination and remediation efforts.
In the late 1970’s, the introduction of Superfund Cleanup regulations established new safety standards for personnel working at industrial cleanup sites. HNU Systems, a company that patented and built the first commercially available hand-held PID, was selected to work with the Environmental Protection Agency’s (EPA) rapid response team to help train individuals to deal with chemical spills due to transportation issues. Using the HNU PID, teams could determine when there was sufficient risk from volatile organic chemicals such that personnel needed to use a hazmat suit and self-contained breathing apparatus. Portable, hand-held PIDs allowed workers to quickly identify potentially dangerous conditions, so they could take action to reduce hazards.
Back in the laboratory, the PID technology, which does not destroy samples, was also used in tandem with gas chromatography to analyze samples from Superfund sites, which further facilitated cleanup and remediation efforts.
In May 2011, at a Chemistry of Industrial Hygiene International Year of Chemistry event, EPA contractor Dave Dahlstrom summarized the impact of the handheld PID in honoring John “Jack” Driscoll, the original developer. Dahlstrom said, “I want to thank you personally for saving thousands of lives.”
A report of the Chemistry of Industrial Hygiene event is available at http://analyzersource.blogspot.com/2011/05/chemistry-of-industrial-hygiene.html
This topic was submitted by Jennifer Maclachlan, Managing Director, PID Analyzers, LLC and member of the American Chemical Society.