Cellphone-Based Raman Spectrometer Recognizes Materials in Minutes

Scientists, medical personnel, and others will be able to quickly identify drugs, chemicals, and biological molecules with a handheld device for Raman spectrometry invented by a team at Texas A&M University. The portable Raman spectrometer is suitable for use in remote settings where laboratory-based spectrometers are impractical due to their large size, cost, and power demands.

The Raman spectrometry system integrates lenses, a diode laser, and diffraction and transmission gratings with a cellphone camera. The laser shines light into a sample for spectral analysis. The camera, which is placed facing the transmission grating, records the Raman spectrum of the sample.

A smartphone records the Raman spectrum of an unknown material (an ethanol solution, in this example) for further analysis. Courtesy of Texas A&M University Engineering.

When the handheld spectrometer is paired with the appropriate application or database on the cellphone, it can read the spectral data provided by the camera and perform a detailed analysis of the chemical composition and molecular structure of the sample, based on its Raman spectrum. In this way, the handheld spectrometer enables rapid identification of materials on-site.

A traditional Raman spectrometer can take several hours or even days to identify unknown substances through extensive sampling and laboratory analysis. The handheld device, in addition to identifying samples much faster than a traditional spectrometer, costs much less to build and use.

In a hospital or urgent care setting, medical personal could use the new spectrometer to rapidly detect pathogens, instead of waiting days for a conventional spectrometer to identify an unsafe substance. In the field, scientists could use the handheld device to noninvasively identify potentially harmful chemicals or materials.

“It’s a small device that can tell you the composition of a particular system, material, or sample,” said Peter Rentzepis, a professor in the Department of Electrical and Computer Engineering at Texas A&M. “You can even have it in your pocket.”

Rentzepis holds a patent for the handheld, cellphone-based Raman spectrometer system. Former graduate students Dinesh Dhankhar, a system engineer at Thermo Fisher Scientific, and Anushka Nagpal, a process engineer at Intel Corporation, are co-inventors of the device.