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High speed low noise multiplexed three color absorbance photometry
Khaled M Dadesh1, G K Kurup, Amar S Basu
1Electrical and Computer Engineering Department, Wayne State University, Detroit, MI 48202, USA. k_kadesh@wayne.edu
Summary
This study introduces frequency division multiplexing (FDM) for cost-effective multicolor photometry. The new high-frequency FDM approach uses a single detector to achieve multi-wavelength absorbance measurements, reducing system costs.
Area of Science:
- Analytical Chemistry
- Spectroscopy
- Biophotonics
Background:
- Multispectral photometry is crucial for flow analysis but is expensive due to multiple optical components.
- Existing spectral detection systems require costly detectors, filters, and optical paths.
Purpose of the Study:
- To present a cost-effective frequency division multiplexing (FDM) method for multi-wavelength absorbance photometry.
- To demonstrate a high-frequency FDM circuit that enhances detection bandwidth and reduces system complexity.
Main Methods:
- Utilized frequency division multiplexing (FDM) with a single light detector and interrogation window.
- Employed high-frequency (hundreds of KHz) FDM to encode light from three LED sources into unique frequency channels.
- Demodulated signals using phase-sensitive electronics, eliminating the need for spectral filters.
Main Results:
- Achieved a tenfold improvement in detection bandwidth compared to previous low-frequency FDM methods.
- Demonstrated simultaneous three-color absorbance detection in solutions and flowing droplet microreactors.
- Validated the potential for significant cost reduction in multicolor photometry systems.
Conclusions:
- High-frequency FDM offers a simplified and economical alternative for multi-wavelength absorbance measurements.
- This electronic multiplexing technique replaces expensive optical components with low-cost electronics.
- The method is suitable for applications like flow injection analysis and flow cytometry.
