THE USE OF MICROCHANNELS FOR SEPARATION AND PRECONCENTRATION: COMPARISON BETWEEN THREE-DIMENSIONAL AND PLANAR CONFIGURATIONS

Simulation and experimental measurements were used aiming at better understanding flow behavior in planar and three-dimensional microchannels used for separation or preconcentration. Two different microchannels configurations were designed, manufactured in acrylic and the surface was modified to adsorb volatile organic compounds (VOCs). Both channels configuration are 73 cm long, 100 µm wide and 40 µm deep. Simulation was carried out in COMSOL (FEMLAB) 3.2® and COSMOS flow 5.0® programs, tracer visualization and quartz crystal microbalance data were evaluated according to chromatographic concepts. Due to the higher axial velocity, planar microchannels are more adequate for preconcentration whereas three-dimensional ones show a good performance in the separation process.