NEMI Method Summary

Method Summary Information

Method Number: 602 Media: WATER
Revision: 40 CFR Part 136, Appendix A (Current Edition)
Method Source: U.S. EPA Engineering and Analysis Division
Subcategory: ORGANIC Analytes in this method
Official Name: Purgeable Aromatics
Descriptive Name Purgeable Aromatics via GC with Photoionization Detector (PID)
Source Info: 4303 USEPA Headquarters
Ariel Rios Building
1200 Pennsylvania Avenue, N. W.
Washington, DC 20460
Citation: EPA Method Guidance CD-ROM (includes MCAWW Methods, and most current EPA Methods)
158718 Byte file
Brief Method
Summary:
 A sample is purged with an inert gas transforming the aromatics to the vapor phase which is collected on an absorbent trap at ambient temperature. After the sample is purged, the trap is then heated, backflushed, and desorbed with the inert gas onto a chromatographic column. The gas chromatograph is temperature programmed to separate the aromatics which are then detected by a photoionization detector. Method 624 can be used for GC/MS confirmation of compound match or interference.
Scope And
Application:
 This method determines target compounds potentially found in municipal and industrial discharges.
Applicable
Conc Range:
 MDL to 1000xMDL (ug/L).
Interferences: (A) Impurities in gas and plumbing: Impurities in the inert gas and organic plumbing system of the purge and trap concentrator tend to be the main cause of interference in the analytical system. The use of non-Teflon tubing and fittings should be avoided.
(B) Contamination during collection: Samples can become contaminated by diffusion of volatile organic compounds across the septum seal during collection and storage. Use Field Blanks to verify possible contamination.
(C) Carryover: Contamination by carry-over in the analytical system can occur, especially in samples that are extremely concentrated. Frequent bakeout and cleaning of the purging system can help prevent carry-over.
QC Requirements: Initial demonstration of laboratory capability and the periodic analysis of laboratory reagent blanks, fortified blanks, and other laboratory solutions as a continuing check on performance.
Sample Handling: Sample should be placed in a 25mL or larger glass vial; screw cap with a hole in the center for a Teflon-faced silicone septum. The sample should not have a headspace and should be kept refrigerated until analysis. If the sample is believed to contain free or combined chlorine, add 10mg/40mL of sodium thiosulfate upon collection and shake vigorously for one minute. Adjust the pH of the sample to that of about 2 with (1+1) HCl while stirring.
Max Holding Time:
 14 days
Sample Prep Met None.
Relative Cost: $201 to $400
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