Researchers Develop a Compact Chromatography Device

Gas chromatography systems are used to help detect and analyze different chemicals that may be in the air. More generally, the systems work by using a technique that separates gases within columns, also known as capillaries. Gases that may be of interest include indoor air pollutants, and more specifically, volatile organic compounds (VOCs). These can include benzene, alkanes, aromatic hydrocarbons, aldehydes, halogenated hydrocarbons, and terpenes.

Researchers from the University of Michigan described in a paper published in 2016, the design of a compact electric gas chromatography device. The device has the advantages of using microfabrication to reduce system cost, being small and versatile, as well as being capable of automated sampling and analysis. Most devices with similar functionality have previously used a mix of micromachining technology to help build the system. However, conventional pumps and valves were used, which made the devices larger, more expensive, and less reliable.

Their design integrates a microfabricated pump, a preconcentrator, separation columns, and capacitive detectors. Of notable mention is the integrated Knudsen pump, which works by thermal transpiration. Consequently, there are no moving parts required, and the device is more reliable and has a longer lifetime.

The device can offer vapor sampling or analytical separation based on the direction the gas is being pumped in. It provides positive pressure for analytical separation and negative pressure for vapor analysis. The separation columns are serpentine channels with diameters of 230um and can be selectively heated to accelerate separation. Lastly, the capacitive detectors are interdigitated electrodes and output signals by means of capacitive change.

The researchers' current implementation has been programmed to detect and analyze 19 different chemicals. In addition, it has been lithographically microfabricated and is fully electric, making it easier to fabricate and overall a more cost-efficient design. The researchers recently have been awarded an "Outstanding Paper" award for their work describing the design published in Microsystems and Nanoengineering. For those interested, their work can be found in great detail after the jump.