Wägli, PhilipChang, Yu-ChiHomsy, AlexandraHvozdara, LubosVan der Wal, PeterHerzig, Hans PeterRooij, DeNico, F.2013-01-312013-01-312013-01-312012https://infoscience.epfl.ch/handle/20.500.14299/88449We present a portable microsystem to quantitatively detect cocaine in human saliva. The chip combines a simple microfluidic method for multiphase liquid-liquid extraction to transfer cocaine from IR-light absorbing saliva to an IRtransparent solvent with the on-chip cocaine detection by IR-waveguide-spectroscopy (QC-laser, waveguide, detector). With our droplet-based extraction method we achieve an additional analyte pre-concentration of at least two orders of magnitude.cocaine detectionliquid-liquid extractionIR-spectroscopydroplet generationdroplet mergingtext::conference output::conference paper not in proceedings