Microfluidic L-L Extraction System Based On Stopped-flow Technique And LCW Capillary

Solvent microextraction has been developed from liquid-liquid (L-L) extraction in recent years as a novel sample pretreatment technique performing liquid-liquid extraction and analyte preconcentration. It has the advantages of low cost, rapid analysis speed and low consumption for organic solvent. At the same time, the development of microfluidic analysis had attracted scientists worked in chemistry, biology, electronic and mechanical engineering.In the first chapter, the development of the microextraction techniques including flow injection L-L extraction, solvent microextraction and solid microextraction was introduced. Their advantages and disadvantages, as well as applications in sample pretreatment were discussed in detail.In the second chapter, the characteristics of Teflon AF liquid core waveguide capillary as well as its applications in analytical chemistry was introduced.In the third chapter, a novel microfluidic liquid-liquid extraction system using stopped-flow technique and liquid core waveguide capillary was developed. The Teflon AF capillary with extremely low refractive index and hydrophobic properties was served as both absorption flow cell and extraction channel. L-L extraction could be performed without requirement for organic/aqueous phase separation.The present system proved to be an efficient, robust and organic solvent-economic means for achieving L-L extraction under stopped flow mode. The use of Teflon AF LCW capillary significantly facilitated the construction of the L-L extraction system and spectrometric detector in routine chemical laboratories. Such systems should be widely applicable for various analytical purposes involving L-L extraction with spectrometric detection.