Evaluation of a Continuous Liquid-Liquid Extractor for Isolation and Concentration of Nonpolar Organics for Biological Testing in the Presence of Humic Materials

摘要

A continuous liquid-liquid extraction system (CLLE) for concentrating trace organics from water into methylene chloride for analysis was designed, built and evaluated. The CLLE uses Teflon coils for phase contact and gravity phase separation. The system includes a self-contained excess solvent distillation chamber, so the methylene chloride is recovered and recycled. Fourteen organic model compounds in the presence of humic material were used as test probes to evaluate the CLLE. Recovery values were determined for these compounds using CLLE and batch LLE (separatory funnel liquid-liquid extraction), and CLLE recoveries were found to be similar to those of batch LLE.