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research article

Microfluidic Droplet-Based Liquid–Liquid Extraction and On-Chip IR Spectroscopy Detection of Cocaine in Human Saliva

Wägli, Philip  
•
Chang, Yu-Chi  
•
Homsy, Alexandra  
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2013
Analytical Chemistry

We present a portable microsystem to quantitatively detect cocaine in human saliva. In this system, we combine a microfluidic-based multiphase liquid-liquid extraction method to transfer cocaine continuously from IR-light-absorbing saliva to an IR-transparent solvent (tetrachloroethylene) with waveguide IR spectroscopy (QC-laser, waveguide, detector) to detect the cocaine on-chip. For the fabrication of the low-cost polymer microfluidic chips a simple rapid prototyping technique based on Scotch-tape masters was further developed and applied. To perform the droplet-based liquid-liquid extraction, we designed and integrated a simple and robust droplet generation method based on the capillary focusing effect within the device. Compared to well-characterized and commonly used microfluidic H-filters, our system showed at least two times higher extraction efficiencies with potential for further improvements. The current liquid-liquid extraction method alone can efficiently extract cocaine and pre-concentrate the analytes in a new solvent. Our fully integrated optofluidic system successfully detected cocaine in real saliva samples spiked with the drug (500 mu g/mL) and allowed real time measurements, which makes this approach suitable for point-of-care applications.

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Type
research article
DOI
10.1021/ac401606p
Web of Science ID

WOS:000323014000080

Author(s)
Wägli, Philip  
•
Chang, Yu-Chi  
•
Homsy, Alexandra  
•
Hvozdara, Lubos  
•
Herzig, Hans Peter  
•
de Rooij, Nico  
Date Issued

2013

Publisher

Amer Chemical Soc

Published in
Analytical Chemistry
Volume

85

Issue

15

Start page

7558

End page

7565

Subjects

Microfluidic

•

optofluidic

•

microsystems

•

optical MEMS

Peer reviewed

NON-REVIEWED

Written at

EPFL

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Available on Infoscience
August 14, 2013
Use this identifier to reference this record
https://infoscience.epfl.ch/handle/20.500.14299/94152
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