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Published on: March 26, 2013
Cocaine detection by a mid-infrared waveguide integrated with a microfluidic chip.
Yu-Chi Chang1, Philip Wägli, Vincent Paeder
1Ecole Polytechnique Fédérale de Lausanne (EPFL), Institute of Microengineering, Optics & Photonics Technology Laboratory, Rue A.-L. Breguet 2, Neuchâtel, Switzerland. yu-chi.chang@epfl.ch
Lab on a Chip
|July 19, 2012
Summary
This study presents a novel germanium waveguide sensor integrated with microfluidics for cocaine detection in tetrachloroethylene. The device utilizes light absorption for sensitive and specific chemical sensing applications.
Area of Science:
- Optoelectronics
- Chemical Sensing
- Materials Science
Background:
- Microfluidic devices offer miniaturized platforms for chemical analysis.
- Germanium (Ge) waveguides on silicon (Si) substrates are emerging for integrated photonic applications.
- Sensitive detection of illicit substances like cocaine is crucial for security and forensic applications.
Purpose of the Study:
- To develop and demonstrate a novel integrated optofluidic sensor for cocaine detection.
- To leverage the unique optical properties of germanium waveguides for chemical sensing.
- To explore the potential of this device for (bio-)chemical sensing in challenging matrices.
Main Methods:
- Fabrication of a germanium strip waveguide on a silicon substrate.
- Integration of the waveguide with a microfluidic chip for sample delivery.
- Utilizing a quantum cascade laser to emit light at 5.8 μm.
- Measuring the absorption of light by cocaine in tetrachloroethylene (PCE) via the waveguide's evanescent field.
Main Results:
- The germanium waveguide sensor successfully detected cocaine in tetrachloroethylene solutions.
- The detection mechanism relies on the specific absorption of infrared light by cocaine molecules.
- The evanescent field of the waveguide enables sensitive interaction with the analyte.
Conclusions:
- The integrated germanium waveguide-microfluidic device provides a promising platform for sensitive cocaine detection.
- This technology has broad applicability in (bio-)chemical sensing, including environmental monitoring and security.
- Further development could lead to portable and rapid analytical tools.
