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Microfluidic chip-based liquid-liquid extraction and preconcentration using a subnanoliter-droplet trapping technique
Hong Chen1, Qun Fang, Xue-Feng Yin
1Chemistry Department, Zhejiang University (Xixi Campus), 310028 Hangzhou, China.
Lab on a Chip
|June 23, 2005
Summary
This study introduces a microfluidic liquid-liquid extraction method for on-chip sample pretreatment. The system achieves high analyte enrichment factors over 1000 using subnanoliter organic droplets.
Area of Science:
- Analytical Chemistry
- Microfluidics
- Sample Preparation
Background:
- On-chip sample pretreatment is crucial for miniaturized analytical systems.
- Traditional liquid-liquid extraction methods can be time-consuming and require large sample volumes.
Purpose of the Study:
- To develop a robust and simple microfluidic system for subnanoliter liquid-liquid extraction.
- To achieve high preconcentration factors for analytes in aqueous samples.
Main Methods:
- Fabrication of microfluidic chips with micro-recesses to trap organic solvent droplets.
- On-chip liquid-liquid extraction by flowing aqueous samples adjacent to trapped droplets.
- In situ monitoring of extracted analytes using laser-induced fluorescence (LIF).
Main Results:
- Achieved high preconcentration factors exceeding 1000 for butyl rhodamine B.
- Demonstrated quantitative measurement with a linear response from 1 x 10(-9) to 8 x 10(-7) M.
- Obtained a precision of 6.6% relative standard deviation (RSD) for a 10(-7) M standard.
Conclusions:
- The developed microfluidic system offers an efficient method for on-chip sample pretreatment.
- The approach enables high enrichment factors with minimal sample consumption.
- This technology is suitable for sensitive quantitative analysis in microfluidic devices.