Quartz crystal microbalances enable new microscale analytic technique
08 Dec 2010
A new chemical analysis technique developed by a research group at the National Institute of Standards and Technology (NIST) uses the shifting ultrasonic pitch of a small quartz crystal to test the purity of only a few micrograms of material.
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| NIST researcher prepares quartz crystal microbalance disks with samples of carbon nanotubes for for microscale thermogravimetric analysis. Typical sample sizes are about 2 microliters, or about 1 microgram.Credit: Kar, NIST |
Since it works with samples close to a thousand times smaller than comparable commercial instruments, the new technique should be an important addition to the growing arsenal of measurement tools for nanotechnology, according to the NIST team.
As the objects of scientific research have gotten smaller and smaller - as in nanotechnology and gene therapy - the people who worry about how to measure these things have been applying considerable ingenuity to develop comparable instrumentation.
This new NIST technique is a riff on thermogravimetric analysis (TGA), an imposing name for a fairly straightforward concept. A sample of material is heated, very slowly and carefully, and changes in its mass are measured as the temperature increases.
The technique measures the reaction energy needed to decompose, oxidize, dehydrate, or otherwise chemically change the sample with heat.
TGA can be used, for example, to characterise complex biofuel mixtures because the various components vaporize at different temperatures.
