David meets Goliath in chemical sampling

A chemical sampling device smaller than the tip of a fingernail may yield big results for detecting and analysing trace chemicals.

The tool, developed by the US Department of Energy’s Sandia National Laboratories, is a mega miniaturised version of a traditional preconcentrator.

The active area of the device is only two millimetres by two millimetres and has the potential to be integrated with other micro chemical detectors, including a mass spectrometer or an ion mobility spectrometer.

The miniaturised size will allow chemical testing using small hand-held instruments, which in turn may eliminate the need to send samples away to a laboratory.

This, claim Sandia, will allow sampling to take place ‘in the field’ and, according to project leader, Greg Frye-Mason, will revolutionise front-end sampling devices. The micro preconcentrator operates by a small pump pulling air containing a chemical over an adsorbent material.

An electric current flows through a platinum hot plate, heating it up to 200 degrees C. The high temperature causes the chemical to be released from the adsorbent material so it can be analysed by a micro detector system.

It does this because the device is so small that it doesn’t take much current or time to heat up. This small size and planar design make the device ideal for chip-based microanalytical systems, claim Sandia.

The adsorbent material most frequently used in testing the device has been a sol gel developed by Sandia researcher, Jeff Brinker.

The gel can be “tuned” to collect certain types of molecules and not others. The researchers have also tested other adsorbent materials with the microfabricated planar concentrator.