On-chip Liquid-liquid Extraction And Separation Using Digital Microfluidics

In this thesis, on-chip liquid-liquid microextraction and separation using electrowetting on dielectric (EWOD) digital microfluidics was demonstrated by considering room temperature ionic liquid (RTIL) and DI water as two liquid phases, which form immiscible interface with each other. Room temperature ionic liquids (RTILs) have been actively investigated as replacements for the organic solvents and various "task-specific" ionic liquids (TSIL) are being developed which exhibit many attractive properties such as selectivity to specific biomolecules. Liquid-liquid extraction and separation using EWOD digital microfluidic device with model extraction experiments have been demonstrated, one was extraction of organic dye from RTIL (1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [bmim][NTf2]) into DI water. Second one was extraction of iodine (I2) from water into [bmim][NTf2]. This demonstration is the first step towards micro total analysis system (µTAS).An on chip pH dependent partitioning in RTIL's using EWOD operation was performed to demonstrate that pH value of the aqueous solution effect the extraction process. This experiment demonstrates that on chip pH titration and extraction is possible which can lead to High-throughput screening (HTS) synthesis of RTIL's and HTS of protein extraction.