CHARACTERIZATION OF FINE PARTICLE ASSOCIATED ORGANIC COMPOUNDS: INTERLABORATORY COMPARISON AND DEVELOPMENT OF STANDARD REFERENCE MATERIALS (SRM) Joellen Lewtas, Joellen Lewtas, US EPA, National Exposure Research Laboratory Michele M. Schantz and Stephen A. Wise Michele M. Schantz and Stephen A. Wise, NIST, Analytical Chemistry Division

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

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

SRM 1649 & 1649a, Urban Dust Collected in Washington, DC ( ) Baghouse with no size selective inlet Sieved to <125 microns >160 certified and reference values published >50 publications characterizing SRM 1649

Intercomparison Trials: Reference Materials Trial I (Feb-July, 2001) –SRM 1649a sieved to <63 microns –Extract of sieved SRM 1649a Trial II (Winter 2002) –Interim Reference Material Baltimore PM 2.5 Trial III (Goal: ) –Bulk Baltimore PM 2.5 for new SRM (goal to collect 200g)

Target AnalytesLabs 36 PAH 14 Labs 7 Nitro PAH2 Labs 12 Alkanes & Alkenes6 Labs 13 Hopanes, Colestanes, & Sterols5 Labs 18 Carbonyls & Acids 5 Labs Aldehydes, Ketones, Lactones, etc. 8 Phenols none 8 Phenols none

Participating Laboratories California Air Resources BoardRice Univ. (Houston Supersite) Mike PooreMatt Fraser Desert Research Institute (Fresno SS)UCLA (So. Cal SS/ PM Center) Barbara ZielinskaTony Miguel Florida Int. U. (Baltimore & Pittsburg SS)Univ. of Miami (Atlanta SS) Wolfgang RoggeRod Zika Lovelace Respiratory Research InstituteU.S. EPA-RTP/Univ NC Jake McDonaldMike 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 CarolinaU.S. EPA-ORD-NRMRL John KucklickDean Smith/Mike Hays

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

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

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

Next Inter-Laboratory Trial Trial II (Winter 2002) –New Interim Reference Particles Baltimore PM 2.5Baltimore PM 2.5 Collected in Collected in Calibration Standards Requirement to report Trial I results Expanding Target Analytes where possible

Interlab Trial I: Design Samples Prepared and Shipped by NIST –NIST SRM 1649a: 500 mg particles –Air Particulate I (SRM 1649a sieved to <63 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

+30% CL +95% CL Certified value

75% 50% 25% Assigned value z=+3 z=+2 z=+1 (+25%) assigned value z= -1 z= -2 z= -3

Summary of Accuracy of PAH Data Air Particulate Extract –Eliminating 1 lab with z-scores generally >3 –Remaining labs z-scores: Less than 10% of the data had z-scores > 2 Air Particulate –Eliminating 1 lab with z-scores > 3 –Remaining labs z-scores: Less than 10 % of the data had z-scores >2 7/13 Labs had less than 3% of the z-scores >2

Summary of Accuracy of PAH Data Air Particulate Extract –Eliminating 1 lab with z-scores generally >3 –Remaining labs z-scores: Less than 10% of the data had z-scores > 2 Air Particulate –Eliminating 1 lab with z-scores > 3 –Remaining labs z-scores: Less than 10 % of the data had z-scores >2 7/13 Labs had less than 3% of the z-scores >2