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Preshious Rearden, Ph.D.
Senior Applications Chemist
prearden@1stdetect.com
GCC - October 20, 2015

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Air Toxic Monitoring
US EPA Requires Oil Refineries To Monitor Benzene Levels
 Other Hazardous Air Pollutants (HAP) include 1,3-butadiene, toluene, ethylbenzene,
and xylenes
 Method 325 established by the EPA for fenceline monitoring of benzene at petroleum
refineries
• Method sets standards for sampler placement, sample collection, preparation, and
analysis
• Recommends a passive sampling approach
‒ 12 to 24 passive samplers placed at 15 to 30 degree intervals along the perimeter
of each refinery
‒ Sampling cycle: 14 days

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Passive Sampling - Limitations and Challenges
Passive Sampling
 Samples analyzed off-line
 Inability to identify emission source
Miniature Mass Spectrometer As An Alternative
Approach To Passive Sampling

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iONTRAC
Why iONTRAC?
 Program and monitor gas streams in real-time
 Data from unused channels stored for future analysis
 No carrier gases required
 Operator controlled or autonomous unattended operation
 Continuous monitoring
 Out-of-spec product alarms
 Cost Effective
 Miniature ion trap mass spectrometer
 Mass Range: 35 – 500 amu
 Dynamic Range: 2 orders of magnitude
 Gases Monitored: User programmable (up to 8 ions)

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GOAL
To Demonstrate the Feasibility of the iONTRAC to Monitor HAPs
 Monitor benzene and ethylbenzene excursions
 Evaluate the iONTRAC’s performance under ambient conditions

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Ambient Monitoring Technical Approach
 iONTRAC equipped with a preconcentrator utilizing a Carbopack X sorbent
• Sampling Time: 70 s
• Desorption Time: 60 s
 Instrument was placed in parking lot at 1st Detect’s facility in Webster TX
 System challenged with benzene and ethylbenzene at varying distances
 Mixtures of benzene and ethylbenzene analyzed
 Meteorological data recorded with each simulated emission
 Sampling Mode: Continuous
 Sample period: 5 days
• Hold Time: 200 s
• Desorption Temp: 300C

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Experimental Set-up
iONTRAC
Weather Station
180 ft
Excursion

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Baseline Recovery
Benzene
Ethylbenzene
Removed Sample
180 ft Excursion
m/z = 78
m/z = 91
m/z = 106
Intensity(a.u.)Intensity(a.u.)

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Reproducibility
Added BenzeneBenzene
Intensity(a.u.)

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Meteorological Effects
Wind Speed and Direction
3mphWNW
3mphN
3mphS
3mphENE
3mphE
iONTRAC
Sample
BenzeneToward iONTRAC
Away from iONTRAC
Intensity(a.u.)

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VOC Detection
Benzene and Ethylbenzene
Benzene (m/z = 78)
Ethylbezene (m/z = 91)
Ethylbezene (m/z= 106)
100 ft
Intensity(a.u.)

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Detection Levels
Benzene
Benzene and Ethylbenzene Detected at 200 ft
20 ft
Intensity as a Function of Distance
Intensity(a.u.)
Avg.Intensity(a.u.)
Intensity(a.u.)
200 ft

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Summary
 iONTRAC offers continuous real-time monitoring of VOCs in
ambient air with:
• Rapid clear down rates (< 2 min)
• Stable and rapid response time
• Detection VOCs levels to a least 200 ft
• Simultaneous monitoring of multiple VOCs
• Faster detection times than passive sampling (<5 min)

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Future Directions
 Optimize sampling and detection time
 Test additional compounds
 Increase the number of sampling ports on the iONTRAC
 Test units on-site at petroleum refineries
Where Do We Go From Here?

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Acknowledgements
Corey Stedwell, Ph.D.
Daniel DeBord, Ph.D.
Madonna Mamerow, Ph.D.
Parminder Kaur, Ph.D.
James Wylde, Ph.D.
David Rafferty

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Thank You!

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Questions?