Three-dimensional microchannels as a simple microreactor

The aim of this work is the production of a simple and compactable device able to remove hydrocarbons from a gaseous sample. The device is composed of a microstructure, inlet/outlet, heating and detection systems. The microstructure (microreactor) corresponds to a manifold formed by an array of 192 three-dimensional microchannels, 40 μm wide and 8 mm long each. Microchannels surface was modified by electroless plating copper deposition in order to promote catalysis. The structure can be heated up to 300 °C in a few seconds. The flow mechanisms in the structure and the heating properties were simulated using FEMLAB 3.2b and COSMOS® 5.0 packages, respectively. The microchannels were exposed to volatile organic compounds during catalysis. An inexpensive tin oxide sensor and correspondent electronic coupled to computer storage data provided detection. Catalysis occurred and could remove at least 10 μg of n-hexane in a single batch, but not 2-propanol. This simple miniaturized device is compact, low-cost and can be used not only for sample pretreatment in microanalysis but also in synthesis of new chemical compounds.