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Published on: January 20, 2023
Improving sensitivity in micro-free flow electrophoresis using signal averaging.
Ryan T Turgeon1, Michael T Bowser
1University of Minnesota, Department of Chemistry, Minneapolis, MN 55455, USA.
Electrophoresis
|March 26, 2009
Summary
Signal averaging multiple images significantly enhances sensitivity in microfluidic free-flow electrophoresis (microFFE). This method improved signal-to-noise ratios by up to 80-fold, achieving low detection limits for fluorescein.
Area of Science:
- Analytical Chemistry
- Microfluidics
- Separation Science
Background:
- Microfluidic free-flow electrophoresis (microFFE) separates analytes in continuous streams within a planar channel under an electric field.
- The continuous nature of microFFE suggests potential for enhanced sensitivity using techniques from spectroscopy and imaging.
Purpose of the Study:
- To investigate signal-to-noise (S/N) ratio improvements in microFFE through image averaging.
- To determine the achievable detection limits using this signal averaging approach.
Main Methods:
- Acquisition and averaging of multiple images from microFFE separations.
- Analysis of signal-to-noise ratio improvements as a function of the number of averaged images.
- Determination of detection limits for fluorescein using the optimized imaging protocol.
Main Results:
- A 20-24 fold S/N improvement was achieved by averaging 500 images (over 2 minutes).
- Up to an 80-fold S/N improvement was observed by averaging 6500 images.
- Detection limits as low as 14 pM for fluorescein were achieved, despite a non-ideal optical setup.
Conclusions:
- Signal averaging of multiple images is an effective strategy to enhance sensitivity in microFFE.
- The primary limitation to prolonged signal averaging is the stability of the microFFE separation, with bubble formation at electrodes after 20 minutes disrupting flow.
- Further improvements are contingent on addressing the long-term stability challenges in microFFE devices.
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