Navigation Links
Quartz crystal microbalances enable new microscale analytic technique

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. 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 smalleras in nanotechnology and gene therapythe 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 characterize complex biofuel mixtures because the various components vaporize at different temperatures. The purity of an organic sample can be tested by the shape of a TGA plot because, again, different components will break down or vaporize at different temperatures. Conventional TGA, however, requires samples of several milligrams or more of material, which makes it hard to measure very small, laboratory-scale powder samplessuch as nanoparticlesor very small surface chemistry features such as thin films.

What's needed is an extremely sensitive "microbalance" to measure the minute changes in mass. The NIST group found one in the quartz crystal microbalance, essentially a small piezoelectric disk of quartz sandwiched between two electrodes. An alternating current across the electrodes causes the crystal to vibrate at a stable and precise ultrasonic frequencythe same principle as a quartz crystal watch. Added mass (a microsample) lowers the resonant frequency, which climbs back up as the microsample is heated and breaks down.

In a new paper.** the NIST materials science group demonstrates that their microbalance TGA produces essentially the same results as a conventional TGA instrument, but with samples about a thousand times smaller. They can detect not only the characteristic curves for carbon black, aluminum oxide and a sample organic fluid, but also the more complex curves of mixtures.

"We started this work because we wanted to analyze the purity of small carbon nanotube samples," explains analytical chemist Elisabeth Mansfield. More recently, she says, they've applied the technique to measuring the organic surface coatings biologists put on gold nanoparticles to modify them for particular applications. "Measuring how much material coats the particles surface is very hard to do right now," she says, "It will be a really unique application for this technique."

The prototype apparatus requires that the frequency measurements be made in a separate step from the heating. Currently, the team is at work integrating the microbalance disks with a heating element to enable the process to be simultaneous.


Contact: Michael Baum
National Institute of Standards and Technology (NIST)

Related biology news :

1. X-ray crystallography reveals structure of precursor to blood-clotting protein
2. New type of liquid crystal promises to improve performance of digital displays
3. How do your crystals grow?
4. A crystal ball for predicting the effects of global climate change
5. Cholesterol crystals incite inflammation in coronary arteries
6. Ancestral Eve crystal may explain origin of lifes left-handedness
7. Researchers envision high-tech applications for multiferroic crystals
8. Scientists watch as peptides control crystal growth with switches, throttles and brakes
9. A crystal ball for brain cancer?
10. Nanocrystals reveal activity within cells
11. Scripps scientists create first crystal structure of an intermediate particle in virus assembly
Post Your Comments:
Related Image:
Quartz crystal microbalances enable new microscale analytic technique
(Date:10/13/2015)... MATEO, Calif. , Oct. 13, 2015 ... real-time, machine-based learning to analyze big data and minimize ... today with Emailage , an innovative fraud prevention ... leverage transactional risk based on a user,s email address. ... a machine learning solution that combines email risk assessment ...
(Date:10/13/2015)... 13, 2015 Dragon Capital Group Corp. ... China , announced today that its wholly ... received a contract for Multi-Format Naked Eye 3D System for ... $450,000 for the project that is expected to be completed ... 35% in gross profits. --> ...
(Date:10/13/2015)... , Oct. 7, 2015 Research and ... the "India Biometrics Authentication & Identification Market - ... --> --> ... $823.46 million in 2014 to $2.06 billion in 2020 ... 2020. India . Growing ...
Breaking Biology News(10 mins):
(Date:10/13/2015)... ... , ... The shortlist of finalists for the Pistoia Alliance President’s Startup Challenge ... from across Europe and the USA. , The Startup Challenge 2015 has seen startup ... in life sciences R&D, with over 30 entries submitted. A panel of expert judges ...
(Date:10/13/2015)... , ... October 13, 2015 , ... ... Universal SuperHeat Controller/Sensor (USHX) product, launches today on the Android smartphone platform. Southern ... system with DMQ’s remote control and monitoring capability for the first time to ...
(Date:10/13/2015)... , Oct. 13, 2015  Amgen (NASDAQ: ... and Cocoon Biotech, Inc. are Amgen,s 2015 selection for ... space at LabCentral. LabCentral is an innovative, shared laboratory ... startups. Cambridge, Mass. ... ways to deliver potential life-changing therapies. --> ...
(Date:10/13/2015)... SUNNYVALE, Calif. , Oct. 13, 2015  Cepheid ... the quarter ending September 30, 2015. ... financial results, total revenue for the third quarter of ... net loss per share is expected to be approximately ... financial results, non-GAAP net loss per share for the ...
Breaking Biology Technology: