A gravity driven micro flow injection wetting film extraction system on a polycarbonate chip

Area of Science:

• Analytical Chemistry
• Microfluidics
• Separation Science

Background:

• Trace analyte concentration is crucial for sensitive detection in various analytical applications.
• Existing methods often require large sample volumes and complex procedures.
• Microfluidic systems offer miniaturization and enhanced efficiency for chemical analysis.

Purpose of the Study:

• To develop a micro flow injection wetting film liquid-liquid extraction system for trace analyte concentration.
• To integrate on-chip extraction with sensitive detection.
• To optimize the system for improved performance and reduced sample consumption.

Main Methods:

• Fabrication of a hydrophobic channel on a polycarbonate chip to support a wetting film.
• Utilizing hydrostatic pressure for fluid manipulation.
• Sequential injection of aqueous sample and organic solvent.
• On-chip detection using a laser-induced fluorescence detector.
• Investigation of parameters like pressure, coating time, channel length, sampling volume, and sample acidity.

Main Results:

• Achieved a 24-fold enrichment factor for butyl rhodamine B.
• Obtained a detection limit of 6.0 x 10(-9)M with a sampling rate of 19 h(-1).
• Demonstrated high reproducibility with a relative standard deviation of 1.5% over eleven runs.
• Required only 3 microL of sample solution for analysis.

Conclusions:

• The developed micro flow injection system is effective for trace analyte preconcentration.
• The system offers high sensitivity, efficiency, and reproducibility for on-chip analysis.
• This approach holds promise for miniaturized analytical systems requiring minimal sample volumes.