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: Bomb-detecting lasers could improve security checkpoints

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/… ensity_standards.cfm.

add to favorites email to friend print save as pdf

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

Spin-based electronics: New material successfully tested

23 hours ago

Spintronics is an emerging field of electronics, where devices work by manipulating the spin of electrons rather than the current generated by their motion. This field can offer significant advantages to computer technology. ...

A transistor-like amplifier for single photons

Jul 29, 2014

Data transmission over long distances usually utilizes optical techniques via glass fibres – this ensures high speed transmission combined with low power dissipation of the signal. For quite some years ...

User comments : 0