A microfluidic preconcentrator for enhanced monitoring of ethylene gas

The design, fabrication and characterization of a microfluidic preconcentrator device for an ethylene gas monitoring system are presented and discussed. The device consists of an array of thick silicon trenches which alternately form a microheater and microchannels that are loaded with Carboxen 1000 adsorbent. A DRIE process was optimized to etch thick silicon microstructures. The silicon structures were sandwiched between two Pyrex glass substrates by anodic bonding. A glass frit was used to connect the inlet/outlet fluidic connections of the device. Clean air was used as a carrier and desorption gas. Up to 100-fold enhancement of 100 ppb ethylene concentration was demonstrated. Various desorption flow rates were tested. The fabricated device can be used for close monitoring of ethylene gas.