Batch fabrication of micro preconcentrator with thin film microheater using Tollen's reaction

A batch fabrication with simple micromachined process based on one photomask and the microfluidic laminar flow patterning technique is developed for a novel micropreconcentrator (μPCT) used in a micro gas chromatograph (μGC). Silver deposition using Tollens' reactions in microfludic channels provides a higher deposition rate and easier microfabrication compared to conventional micromachined technologies for thick metal microstructures (> 200 μm). An amorphous and porous carbon film that functions as an adsorbent is grown on microheaters inside the microchannel. The μPCT can be heated to >300°C rapidly by applying a constant electrical power of ~5 W with a heating rate of 60°C/s. Four volatile organic compounds (VOCs), acetone, benzene, toluene, and xylene, are collected through the proposed novel μPCTs and separated successfully using a 17-m-long gas chromatography (GC) column. Compared with our previous work, the more uniform temperature distribution, more efficient heating rate and smaller peak widths at half height (PWHH) are obtained.