CHARACTERIZATION OF FINE PARTICLE ASSOCIATED ORGANIC COMPOUNDS:

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CHARACTERIZATION OF FINE PARTICLE ASSOCIATED
ORGANIC COMPOUNDS

• INTERLABORATORY COMPARISON AND DEVELOPMENT OF
  STANDARD REFERENCE MATERIALS (SRM)

Joellen Lewtas, US EPA, National Exposure
Research Laboratory Michele M. Schantz and
Stephen A. Wise, NIST, Analytical Chemistry
Division
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PM2.5 Organic Speciation Working Group

• EPA PM Supersites Related Sites
• EPA PM Centers
• National Labs other Research Centers
• Regional and State Laboratories
• NIST, ORNL/NARSTO

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GOAL

• Improve the Characterization and Quantification
  of Organic Compounds Associated with PM2.5
  (Aerosols)
• Standard Reference Materials
• Inter-Laboratory Trials
• Common Analysis of Key Analytes

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SRM 1649 1649a, Urban Dust

• Collected in Washington, DC (1976-77)
• Baghouse with no size selective inlet
• Sieved to lt125 microns
• gt160 certified and reference values published
• gt50 publications characterizing SRM 1649

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Intercomparison Trials Reference Materials

• Trial I (Feb-July, 2001)
• SRM 1649a sieved to lt63 microns
• Extract of sieved SRM 1649a
• Trial II (Winter 2002)
• Interim Reference Material Baltimore PM2.5
• Trial III (Goal 2003-2004)
• Bulk Baltimore PM2.5 for new SRM (goal to collect
  200g)

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Target Analytes Labs 36 PAH 14 Labs 7
Nitro PAH 2 Labs 12 Alkanes Alkenes 6
Labs 13 Hopanes, Colestanes, Sterols 5
Labs 18 Carbonyls Acids 5 Labs Aldehydes,
Ketones, Lactones, etc. 8 Phenols none
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Participating Laboratories
California Air Resources Board Rice Univ.
(Houston Supersite) Mike Poore Matt
Fraser Desert Research Institute (Fresno
SS) UCLA (So. Cal SS/ PM Center) Barbara
Zielinska Tony Miguel Florida Int. U.
(Baltimore Pittsburg SS) Univ. of Miami
(Atlanta SS) Wolfgang Rogge Rod Zika Lovelace
Respiratory Research Institute U.S. EPA-RTP/Univ
NC Jake McDonald Mike Tolocka John
Volckens Environmental Technology Center
Univ.Washington (Seattle PM Center) Gary
Poole/Chung Chiu Chris Simpson NIST-Maryland
U.S. EPA-Region 10 Michele Schantz Steve
Reimer NIST-South Carolina U.S.
EPA-ORD-NRMRL John Kucklick Dean Smith/Mike
Hays
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Range of Analysis Methods

• Extraction solvents including
• Dichloromethane
• Benzene
• Isopropanol
• Hexane
• Acetone
• Acetonitrile
• Ethylacetate
• Hydroxytoluene
• Phenol
• Extraction techniques including
• sonication
• soxhlet
• microwave-assisted
• pressurized fluid extraction

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Range of Analysis Methods, continued

• Extraction times ranging from 15 minutes to 20
  hours
• Extract clean-up including
• filtering
• concentration by blowdown or evaporation
• solid-phase extraction
• solvent exchange
• HPLC fractionation
• Analysis Techniques
• GC/MS - Electron Ionization
• GC/MS Negative Chemical Ionization
• HPLC
• Standards
• Internal versus external
• Calibration from 3 to 10 points

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Results

• Good data return and agreement for many PAH
• - Surprisingly, agreement better for SRM1649a
• than for the extract
• Poor data return for more exotic compounds
• - Not sufficient information for a consensus
  value

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Next Inter-Laboratory Trial

• Trial II (Winter 2002)
• New Interim Reference Particles
• Baltimore PM2.5
• Collected in 2000-2001
• Calibration Standards
• Requirement to report Trial I results
• Expanding Target Analytes where possible

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Interlab Trial I Design

• Samples Prepared and Shipped by NIST
• NIST SRM 1649a 500 mg particles
• Air Particulate I (SRM 1649a sieved to lt63
  microns) 500 mg particles
• Air Particulate Extract I (Extract of sieved SRM
  1649a) 5 ampoules of 1.2 ml each
• Extracted by Pressurized Fluid Extraction using
  Dichloromethane
• Labs Requested to analyze each of 3 replicate
  samples and to concurrently analyze the NIST SRM
  1649a Urban Dust

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30 CL 95 CL Certified value
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z3 z2 z1 (25) assigned value z -1
z -2 z -3
75 50 25 Assigned value
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Summary of Accuracy of PAH Data

• Air Particulate Extract
• Eliminating 1 lab with z-scores generally gt3
• Remaining labs z-scores
• Less than 10 of the data had z-scores gt 2
• Air Particulate
• Eliminating 1 lab with z-scores gt 3
• Remaining labs z-scores
• Less than 10 of the data had z-scores gt2
• 7/13 Labs had less than 3 of the z-scores gt2

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Summary of Accuracy of PAH Data

• Air Particulate Extract
• Eliminating 1 lab with z-scores generally gt3
• Remaining labs z-scores
• Less than 10 of the data had z-scores gt 2
• Air Particulate
• Eliminating 1 lab with z-scores gt 3
• Remaining labs z-scores
• Less than 10 of the data had z-scores gt2
• 7/13 Labs had less than 3 of the z-scores gt2