A cascaded micro preconcentration approach for extraction of volatile organic compounds in water

This paper reports a novel method for extraction of volatile organic compounds (VOCs) from aqueous matrix using MEMS technology. The method consists of connecting two microfabricated chips in a tandem configuration. The first chip is comprised of 7mm×7mm×0.24mm etched cavity inside 12mm square chip and is mainly used for storing aqueous sample while the second one has an array of parabolic reflectors inside its 7mm×7mm×0.24mm cavity. The parabolic reflectors are coated with an adsorbent material for capturing VOCs introduced by passing an inert gas through the former stage. The concept presented herein, is to minimize the contact between aqueous sample and the adsorbent bed. Direct injection of aqueous sample into the GC system causes problems such as flashback in the injector liner, saturation and degradation of column stationary phase and may even result in extinguishing flame ionization detector (FID). This approach eliminates abovementioned problems and can be used to develop an inexpensive handheld water sensor.