Use of handheld Raman spectroscopes on the horizon

In the not-too-distant future, a corn producer will be able to walk into the field and check the crop for nutrient value, disease and other factors using a device the size of a cellphone.

And as a bonus, it will be done cheaper and more accurately than it now is.

Researchers at Texas A & M University are developing a device that uses Raman spectroscopy to measure the nutrient value and other features of crops.

Named for Indian physicist C.V. Raman, the device uses lasers to conduct the measurements.

Dmitry Kurouski, a professor of biochemistry and biophysics at Texas A & M, said it uses an optical technique based on scattering of light.

When a laser is shined on an object, it causes two types of light scattering at the molecular level. The laser hits photons — basically particles of light — and causes them to scatter. Some of them show no change in energy, but a small number, perhaps one in a million, exchange energy with photons, causing them to vibrate and either lose or gain energy. That loss or gain is determined by the photon’s chemical structure. A Raman spectroscope collects those and gives a reading of the nutrient content of the plant.

Raman spectroscopy is used in a number of different areas, but “when we apply it to agriculture, we see exactly what is the chemical composition of the sample that we shine laser light on,” Kurouski said.

If it’s being used on corn, for example, depending on how the device is calibrated it can tell levels of carbohydrate, starch, protein or fiber.

That currently can be done in a laboratory, but doing so is labor-intensive, because the sample of grain being studied must be homogenized, weighed, ground and purified. That requires the grain to be destroyed.

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