The researchers have taken gas chromatography and mass spectrometry (GC-MS) and shrunk them to fit in a device the size of a computer mouse. Eventually, the team led by MIT Professor Akintunde Ibitayo Akinwande plans to shrink the detector to the size of a matchbox. Making the device small reduces the amount of power it consumes and enhances its sensitivity to trace amounts of gases, Akinwande says.
The detector uses GC-MS to identify gas molecules by their electronic signatures. Current portable GC-MS machines, which take about 15 min to produce results, are about 1.2 ft3 and use 10,000 joules of energy. The MIT version consumes about four joules and gets results in about 4 sec.
The detector, which researchers plan to complete within two years, could help protect water supplies, detect hazardous gases in the air, or be used for medical diagnostics.
The analyzer breaks gas molecules into ionized fragments, which are detected by their specific charge (ratio of charge to molecular weight). Gas molecules are broken apart by stripping electrons from molecules, or by bombarding them with electrons stripped from carbon nanotubes. Fragments are then sent through a long, narrow electric field. At the end of the field, the ions’ charges are converted to voltage and measured by an electrometer, which identifies the molecules’ distinctive electronic signature.
The research is funded by the Defense Advanced Research Projects Agency and the U.S. Army Soldier Systems Center in Natick, Mass.