Ultrasmall Particles
Why in News:
- Researchers from IIT Madras and IISER Kolkata have developed a method to detect minute quantities of chemicals in solution.
How did they achieve this
- They use a variation of absorption spectroscopy that surpasses the systemic limits imposed by conventional absorption spectroscopy.
- With this technique, they can, in principle, illuminate the insides of cells and detect minuscule quantities of substances present there.
What is Absorption spectroscopy
- Absorption spectroscopy is a tool to detect the presence of elements in a medium. Light is shone on the sample, and after it passes through the sample is examined using a spectroscope. Dark lines are seen in the observed spectrum of the light passed through the substance, which correspond to the wavelengths of light absorbed by the intervening substance and are characteristic of the elements present in it. In usual methods, about a cubic centimetre of the sample is needed to do this experiment.
- In the newly developed method, minute amounts of dissolved substances can be detected easily.
- The novel method by the IIT- IISER team employs a version of absorption spectroscopy, which takes advantage of the quantum emission capabilities of erbium-doped sodium yttrium fluoride nanoparticles, which can absorb and re-emit red, blue, and green light.
- Substances in the sample would absorb the emission from these micro particles. The nature of the absorbing material could be determined by analysing the absorption spectra.
Significance of this study
- Surpasses the limits of conventional absorption spectroscopy based on the Abbe criterion.
- The Abbe criterion sets a natural limit on the size of the object being studied using absorption spectroscopy.
- This technique can be used to study the insides of cells and detect even minuscule quantities of substances present there.
- Can measure individual molecules, see an absorption spectroscopy of a single DNA or protein molecule
Reference:
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