Raman Spectroscopy

  Jul 24, 2020

Raman Spectroscopy

Q. What is Raman Spectroscopy?

A. Raman Spectroscopy is a non-destructive chemical analysis technique which provides detailed information about chemical structure, phase and polymorphs, crystallinity and molecular interactions. It is based upon the interaction of light with the chemical bonds within a material.

Q. What is Raman Scatter?

A. It is a light scattering technique, whereby a molecule scatters incident light from a high intensity laser light source.

Most of the scattered light is at the same wavelength (or color) as the laser source and does not provide useful information – this is called Rayleigh Scatter.

However a small amount of light (typically 0.0000001%) is scattered at different wavelengths (or colours), which depend on the chemical structure of the analyte – this is called Raman Scatter.

Q. Why is this in news?

A. Researchers have turned to Raman Spectroscopy to detect RNA viruses present in saliva samples. It has been reported that novel coronavirus is found in sufficient numbers in human saliva.

Q. How was it carried out?

A. For the study, the researchers spiked saliva samples with non-infectious RNA viruses and analysed it with Raman Spectroscopy. They analysed the raw Raman Spectroscopy data and compared the signals with both viral positive and negative samples.

Statistical analysis of all the 1,400 spectra obtained for each sample, showed a set of 65 Raman spectral features was adequate to identify the viral positive signal.Q. What is its significance?

A. This conceptual framework to detect RNA viruses in saliva could form the basis for field application of Raman Spectroscopy in managing viral outbreaks, such as the ongoing COVID-19 pandemic.

However, in case of COVID 19 pandemic, it can be used only for screening. Because, the RNA virus detected could be a common cold virus as well or any other RNA virus such as HIV. It doesn’t look for COVID-19 viral-specific signature.

But, the main benefit here is that this whole process of data acquisition and analysis can be performed within a minute. Since no additional reagent is needed there is no recurring cost.

A portable (bench-top or handheld) Raman spectrophotometer installed at the port of entry such as airports or any point of care (in the field) can quickly screen passengers within minutes.