Acid/Neutral Continuous Liquid/Liquid Extraction of Priority Pollutants and Hazardous Substance List Compounds

摘要

Continuous liquid-liquid extraction was compared to manual extractions per EPA Method 625, but employing an acid-neutral scheme. The results from EPA performance evaluation (quality control) wastewater, Superfund, and RCRA samples are compared using the two extraction techniques. Continuous liquid-liquid extractions following an acid-neutral scheme were compared to those following a base-neutral scheme. The acid-neutral continuous extraction scheme was determined to be effective elegant and labor saving. Emulsion formation was reduced and the recoveries of phenol, 4-nitrophenol, pentachlorophenol and benzoic acid were significantly improved by using the continuous extractor. The acid-neutral scheme as opposed to the Method 625 base-neutral extraction was found to greatly improve the recovery of dimethyl-, diethyl-, di-n-butyl-, and n-butyl benzyl phthalate esters. The levels of target and additional compounds extracted using a continuous extractor from the environmental samples tested equaled or exceeded those obtained from manually extracted samples.