New spectrometry standard for handheld chemical detectors aids first responders

Oct 25, 2013
Christopher Neary of the NIST Environmental Management Group demonstrates the use of a handheld Raman spectrometer to determine the identity of an unknown sample. Credit: Linda Joy/NIST

When it comes to detectors for dangerous chemicals, toxins or nefarious germs, smaller and faster is better. But size and speed must still allow for accuracy, especially when measurements by different instruments must give the same result.

The recent publication of a new standard—a culmination of years of research at the National Institute of Standards and Technology (NIST)—provides confidence that results from handheld chemical detectors can be compared, apples-to-apples.

Such detectors are used by emergency responders to check for the presence of explosives or toxic chemicals that threaten public safety. Quality control managers in the pharmaceutical industry use them to verify the identity of chemicals going into their production lines.

The new standard, published recently by ASTM International, is intended as a guide to correct the output from different handheld Raman , so that different instruments produce the same result for the same sample.

Raman spectrometers identify chemicals by shining laser light on a sample and detecting the very small changes in the wavelength of that light as it is re-emitted from the sample. However, spectrometers from different manufacturers can produce signals with different peak intensities. These differences can be confusing, particularly if first responders from different agencies use different instruments and get differing results on an unknown sample in the field.

"Our goal is that people get the same answer for the same sample on any machine," says NIST chemist Steven Choquette.

His team developed a series of NIST Standard Reference Materials (SRMs) that are used to correct Raman systems with differing excitation lasers. These standards enable the correction of the differences in peak intensities reported for the same sample by different Raman spectrometers. They then continued to work with spectrometer manufacturers to develop an industry consensus standard to enable comparisons among Raman spectrometers. Their work was funded by the NIST Law Enforcement Standards Office (OLES) and the Department of Homeland Security.

Explore further: What's fair?: New theory on income inequality

More information: The newly published industry consensus standard, Standard Guide for Relative Intensity Correction of Raman Spectrometers (designated as E2911-13), is available from ASTM International at www.astm.org/Standards/E2911.htm. For more on OLES, visit www.nist.gov/oles. For more on the NIST reference materials for fluorescence and Raman spectroscopy, visit www.nist.gov/mml/bbd/bioassay/fluorescence_raman_intensity_standards.cfm.

Related Stories

New NIST SRM supports the fight against terrorist bombings

May 30, 2012

The National Institute of Standards and Technology (NIST) has released a new standard reference material (SRM) to aid in the detection of two explosive compounds that are known to be used by terrorists. Researchers ...

Recommended for you

What's fair?: New theory on income inequality

9 minutes ago

The increasing inequality in income and wealth in recent years, together with excessive pay packages of CEOs in the U.S. and abroad, is of growing concern, especially to policy makers. Income inequality was ...

Scientists one step closer to mimicking gamma-ray bursts

6 hours ago

Using ever more energetic lasers, Lawrence Livermore researchers have produced a record high number of electron-positron pairs, opening exciting opportunities to study extreme astrophysical processes, such ...

On-demand X-rays at synchrotron light sources

May 26, 2015

Consumers are now in the era of "on-demand" entertainment, in which they have access to the books, music and movies they want thanks to the internet. Likewise, scientists who use synchrotron light sources ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.