Liquid-liquid extraction (LLE) is a useful extraction technique for highly complex samples, however, it suffers from being slow due to mass transfer limitations. Carbon dioxide expanded liquids (CXL) is a good replacement of traditional organic solvents for extraction, and for the first time, the use of CXL in LLE was evaluated. An equipment consisting of a high-pressure view cell with on-line gas chromatography analysis was built and validated, and thereafter used to obtain novel phase equilibria data of the CO₂/n-octanol/water system. The system was connected on-line to HPLC to study the potential of CO₂-expanded liquid-liquid extraction (CXLLE) of pharmaceutical contaminants in water. In comparison with traditional LLE performed under similar experimental conditions, the addition of CO₂ as a viscosity-lowering entrainer significantly increased the speed of mass transfer. Changes in compound log D (octanol-water distribution ratio) values brought by the CO₂ expansion also proved the possibility of selectivity-tuning in CXLLE.

液-液萃取（LLE）是一种用于高度复杂样品的有用萃取技术，但是由于传质限制，它的速度较慢。二氧化碳膨胀液（CXL）很好地替代了传统的有机溶剂进行萃取，并且首次评估了CXL在LLE中的使用。建造并验证了由带有高压气相色谱仪和在线气相色谱分析的设备组成的设备，此后，该设备可用于获得CO ₂ /正辛醇/水系统的新型相平衡数据。该系统在线连接到HPLC，以研究CO ₂的潜力扩展了水中药物污染物的液-液萃取（CXLLE）。与在类似实验条件下进行的传统LLE相比，添加CO ₂作为降低粘度的夹带剂可以显着提高质量转移的速度。CO ₂膨胀带来的化合物log D（辛醇-水分配比）值的变化也证明了CXLLE选择性调节的可能性。