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Main Title Application of Microwave Energy to the Extraction of Organic Compounds from Solid Samples.
Author W. F. Beckert ; V. Lopez-Avila ; R. Young
CORP Author Midwest Research Inst., Falls Church, VA.; Environmental Monitoring Systems Lab., Las Vegas, NV. Quality Assurance and Methods Development Div.; Environmental Monitoring Systems Lab., Las Vegas, NV.
Year Published 1994
Report Number EPA 600/RDT94/031; EPA/CN-68-C 1-0029
Stock Number PB2014-104186
Additional Subjects Toxicity ; Organic compounds ; Extraction ; Hydrophobic proper ; Solid phases ; Sediments ; Toxic substances ; Solid materials ; Pollutants
Library Call Number Additional Info Location Last
NTIS  PB2014-104186 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 77p
As part of an ongoing evaluation of novel sample-preparation techniques by the U.S. Environmental Protection Agency (EPA), especially techniques that minimize generation of waste solvents, we evaluated microwave-assisted extraction (MAE) of organic compounds from solid materials (or matrices). Six certified reference materials containing polynuclear aromatic hydrocarbons (PAHs) and some base/neutral/acidic compounds, all of which are pollutants of interest to the EPA, were subjected to MAE in a closed-vessel microwave system with hexane-acetone (1: 1) at different temperatures (80 degrees C, 115 degrees C, or 145 degrees C) and for different periods of time (5, lO, or 20 min). For comparison, the same samples were subjected to room-temperature extraction by allowing the same solvent mixture to stay in contact with the solid matrix the same amount of time as the microwave-extracted sample (including any cooling time). Two matrices were also heated in a convection oven at 115 degrees C, for different periods of time, with the same solvent and in the same vessel as the microwave-extracted samples. Whereas the average recovery at room temperature was about 54 percent, the MAE recoveries for 17 PAHs (three of which were deuterated PAHs that were spiked into the matrices) from the six matrices were 72 percent at 80 degrees C, 78 percent at 115 degrees C, and 77 percent at 145 degrees C. The recoveries for the oven-heated samples were similar to those obtained by MAE. MAE was, however, exclusively used in this study because of its easy controllability and convenience. Although the average recoveries by MAE increased slightly with extraction time, the increase was not statistically significant. The performance of the MAE technique varied with the matrix and the analytes. Eleven PAHs had average recoveries in the 65- to 111-percent range, and three compounds (benzo(a)pyrene, benzo(ghi)perylene, and fluorene) had recoveries of 51 percent, 64 percent, and 62 percent, respectively. The spiked-compound recoveries by MAE were 77 percent for anthracene-d(sub 10) 104 percent for benzo(a)anthracene-d(sub 12), and 84 percent for fluoranthene-d(sub 10). Additional experiments with 14 phenols and 20 organochlorine pesticides indicated that MAE is a viable alternative to the conventional Soxhlet/Soxtec and sonication extraction techniques. MAE requires smaller amounts of organic solvents, and sample throughput is increased by shorter extraction times (10 min) and because simultaneous extraction of up to 12 samples is possible.