Abstract
As the first application of pressure-driven microfluidics in forensic toxicology, a microchip-based liquid-liquid extraction for the gas-chromatography assay for amphetamine-type stimulants in urine has been developed. The interface consisting of 1-chlorobutane and alkalized urine was stabilized in the asymmetric microchannel modified partially with the capillarity restricted modification (CARM) method. As a practical demonstration, methoxyphenamine hydrochloride was administered to three healthy volunteers, and the concentration of methoxyphenamine in their urine was determined. © 2006 Society for Chemistry and Micro-Nano Systems.