Preparing Soil Samples for Volatile Organic Compound Analysis,

Three equilibrium headspace and three solvent extraction methods of preparing soil samples for determining volatile organic compounds VOCs were compared. Soil samples were spiked with five gasoline range aromatic compounds and four chlorinated compounds using two different laboratory procedures that limit volatilization and biodegradation losses. All comparisons were made with sample triplicates of one or more soil types. Recovery efficiencies for the preparation methods depended on soil organic carbon content, octanol-water partition coefficients of specific analytes, length of solvent extraction, and the spiking procedure used. In general, methanol extraction was the most robust method for recovering spiked VOCs. Recovery efficiencies for VOCs with tetraethylene glycol dimethyl ether and polypropyleneglycol, as well as three equilibrium headspace methods, varied with the parameters tested.