Laserfiche WebLink
TECHNICAL MEMORANDUM <br /> TO: DOHS-ELAP FROM: Dr. Blayne Hartman <br /> ATTN: Mr. Richard Spinner & Staff DATE: March 3, 1992 <br /> TOTAL # OF PAGES: 3 <br /> SUBJECT: BTEX Analysis by Liquid-Liquid Extraction <br /> TEG conducted a series of tests to compare the accuracy of BTEX analysis of waters by liquid- <br /> liquid extraction.versus standard purge & trap methodology. The motive for conducting these <br /> tests was to test whether alternative methods besides purge & trap are suitable so that many of the <br /> problems of purge & trap methodology (poor purge efficiency, instrument blanks, carry-over, <br /> trap break-through) can be eliminated. <br /> PROCEDURE <br /> 33 ml of water were extracted with 1 ml of freon-113 in a closed vial by shaking vigorously for 5 <br /> minutes. 3 ul of the freon was injected into a gas chromatograph equipped with a PID>. <br /> TESTS <br /> Two types of tests were conducted. First, two test samples provided by the EPA were run by <br /> TEG's CA-DOHS certified mobile laboratory in Seattle. These results are attached along with <br /> the cover letter commending our laboratory for the excellent results. <br /> In a second test, TEG's Leucadia laboratory spiked a water sample and performed a liquid-liquid <br /> extraction as described above. Both the solvent and headspace concentrations were measured to <br /> test whether the volatiles partition into the water, solvent, or vial headspace. The results were as <br /> follows: <br /> Mass in water after spike: 12000 ng <br /> Mass in solvent after extraction: 10956 ng (91.3%) <br /> Mass in headspace: 164 ng (1.4%) <br /> Mass remaining in water: 880 ng (7.3%) <br /> CONCLUSIONS <br /> These 2 independent tests document that liquid-liquid extraction with freon-113 quantitatively <br /> extracts BTEX compounds from water without the potential problems of purge & trap methods. <br /> Y. <br /> Transglobal Environmental Geochemistry <br /> 1 159 Hermes Avenue, Leucadia, CA 92024/(619) 632-0401 /FAX (619) 632-0404 <br />