Wednesday, May 24, 2017

Real-time detection of ppb levels of benzene by gas chromatography/PID

Real-time detection of ppb levels of benzene by gas chromatography/PID




New real-time detection method for benzene at ppb levels using a hand-held GC/PID system with the ability to simultaneously provide real-time data and collect samples for lab verification if necessary.
Scientific/Research Presentation:

#AIHCE, Tuesday June 6, 2017, 11:15am-12:15pm, Seattle, WA, 



F4: Studies in Real Time Detection and Sensor Technology


Authors:
J Driscoll1 , J Maclachlan1

Institutions: 
1PID Analyzers, LLC, Sandwich, MA
Author:
John Driscoll
PID Analyzers, LLC
Co-Author:
Jennifer Maclachlan 
PID Analyzers, LLC
Objective:
Benzene is a known carcinogen and long term exposure to this chemical may result in leukemia. The OSHA permissible exposure limit (PEL) therefore is 1 ppm and the short term exposure limit (STEL) is 5 ppm. EPA has just announced (October 2016) a plan to regulate benzene, at 2.8 ppb, at the fenceline of refineries and chemical plants. It is clear that even low ppb levels of benzene are a health concern so that the measurement of benzene in the workplace at ppb levels should be a concern for industrial hygienists.
Methods:
We have developed a five pound, compact GC/PID system that will utilize a special 10.0 eV/10.2eV lamp to improve the specificity for benzene. We have employed a capillary column to provide a fast, specific, and sensitive method for benzene. As a result, we can detect > 1 % of the PEL. The analysis time for benzene is 1 minute, so, five measurements can be used to determine the STEL. The reproducibility (CV) for benzene at 1 ppm is 1-2% and 4-5% at 1/10th of the PEL.
Results:
A concentrator has been developed that fits on the tip of probe of the analyzer. A valve is selected to determine whether the sample is directed to the GC or the concentrator. The volumetric flow is measured with a calibrated flow sensor in the analyzer and date, time and location are recorded. This adsorbent can returned to the lab for confirmatory analysis of benzene and any other components trapped on the adsorbent.
Conclusions:
Having a simple, effective and accurate real-time method to meet monitoring needs of workers is critical to remain in compliance with the present or new OHSA standards for benzene. This system is designed for multiple users, features a color graphics screen with simple push button operation and remote data collection via Bluetooth.

Hazard Recognition and Evaluation:
Real-Time Detection Systems

Keywords:
Real-Time Detection Systems

Practical Application
How will this help advance the science of IH/OH?
Real-time detection systems help limit worker exposure to chemical hazards. This scientific presentation will discuss the specific hazards and share new tools that will improve the accuracy of detection (without the use of detector tubes) as well as allow operators to collect samples for lab verification while capturing the real-time field analysis data. This equipment is ruggedly designed for a multi-user environment with various levels of technical expertise.




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