Gas chromatography (GC) systems are chemical instruments by which the components of a gaseous mixture can be separated, identified, and the constituent concentrations quantified. Conventional GC systems are large and relatively expensive table-top instruments. Central to the miniaturization of GC systems is microelectromechanical systems (MEMS) technology, especially for the development of complete microGC systems with faster analysis capacity and increased portability. One of the challenges associated with microGC systems lies in fabrication of the micro-preconcentrator to increase measurement sensitivity for analytes of low concentration. To date, carbon nanotubes have been explored to accumulate an analyte; however, steps required for the formation of nanotubes, followed by harvesting and coating of the substrate are time consuming and prone to error and chemical contamination.
University of Michigan researchers have invented new MEMS device for microanalytical systems and components for vapor analysis. The new analyte accumulation device is based on carbon nanotubes grown by chemical vapor deposition on the strip of the metal catalyst, wherein the nanotubes are adapted to accumulate a gaseous or liquid analyte inside a container. Structure, thickness, and density of the carbon nanotubes can be varied to suit the particular function of the microsystem sub-system component. In the case of preconcentrators, varying these parameters can affect capacity and thermal desorption efficiency, whereas for a separation sub-system, similar changes can affect retention and separation of mixture components.
Applications and Advantages
- gas accumulation for sensors or detectors
- carbon nanotube layers can be deposited-nl-in situ and to vary layer properties
- unique application of miniaturized chemical-nl-analysis systems made using Si-microfabrication-nl-technology