Identification is one of the test to identify the functional group of drug substance in the pharmaceutical industry.
Raman spectroscopy is non destructive technique of analysis that provides a complete information of chemical structure of the drug.
Let’s see what are the raman spectroscopy uses advantages and disadvantages in pharmaceutical industry.
But before we will see the background of Raman spectroscopy.
History of Sir C.V. Raman Indian Physicist
Raman Spectroscopy is invented by the Indian physicist Sir C.V. Raman. The name Raman spectroscopy is given on the honour of Sir C.V. Raman who invented this technique.
Sir C.V. Raman awarded with Nobel prize in physics in 1930 for his invention. Sir C.V. Raman is the first asian person who awarded by Nobel prize. Sir C.V. Raman also awarded by Indian government by the Bharat Ratna award in 1954.
Sir Chandrashekhara Venkata Raman ( C. V. Raman) was born on 7 November 1988 and died on 21 November 1970. Sir C.V Raman is basically Tiruchirapalli belong to Tamilnadu state of India.
Here we will see,
Raman spectroscopy uses advantages and disadvantages in pharma
apart from that remaining points also will cover such as,
- Principle of Raman Spectroscopy
- Raman Spectroscopy instrumentation
- How does Raman spectroscopy works?
- Uses of Raman Spectroscopy
- Advantages of Raman Spectroscopy
- Disadvantages of Raman spectroscopy
- Difference between Raman Spectroscopy and IR Spectroscopy
- Types of Raman spectroscopy
- Application of Raman Spectroscopy
1. Principle of Raman Spectroscopy
Raman spectroscopy is based on light scattering technique. Raman spectroscopy is a analytical technique to determine the vibrational energy modes of sample with the help of scattered light. It is qualitative technique to determine functional group of the drug.
” Frequency of small fraction of scattered light is different from frequency of monochromatic incident light.”
It is based on Raman effect. When light transferred from the sample, the lights are scattered in multiple directions.
What is Raman Effect?
Raman effect includes elastic scattering at the same wavelength as the incident radiation and inelastic scattering at the different wavelength due to molecular vibrations.
“Change in the wavelength of light that occurs when a light beam is deflected by sample molecule.”
What is Raman shift?
Raman shift is a difference in energy between incident light and scattered light. The Raman shift is having two different energy bands.
It includes Stoke scattering and anti stoke scattering.
Stoke scattering: When shift at wavelength is higher than that of the incident light is called as Stoke scattering.
Antistoke Scattering: When shift at wavelength is lower than that of the incident light is called as antistoke scattering.
2. Raman spectroscopy instrumentation
Basically Raman Spectroscopy includes three main components first is Laser, sampling interface and spectrometer.
The laser is useful to scan the sample. In spectrometer Fiber optic probe is typically used that provide a maximum sampling interface. The fiber optic probe is easily change the microscopes, gas flow cells, liquid flow cells and remaining sampling parts.
Spectrometer is an important performance factors are small form factor, low power consumption, high resolution, less time and low noise. A proper detector also very important factor.
3. How does raman Spectroscopy works?
Raman spectroscopy is depends on the inelastic scattering of photons, this effect is known as Raman scattering. When the laser light is interact with the molecular vibration, photons and other excitation, resulting in the energy of the laser photons is shifted to up or down.
4. Uses of Raman Spectroscopy
Raman spectroscopy is very useful and qualitative technique. In this technique laser light is used for scanning of the sample.
Uses of Raman spectroscopy are:
- It is useful to determine the vibrational energy of sample molecule as well as rotational and other low energy molecules.
- Raman spectroscopy can provide easy and quick information of sample.
- It can be used to characterized chemical structure and composition of sample molecule.
- Raman spectroscopy can detective even small changes in structure.
- Raman spectroscopy need very less time for identification analysis.
5. Advantages of raman spectroscopy
There are multiple advantages for using of Raman spectroscopy, some of them are listed below.
- Direct scanning of sample can save time and chemical used for analysis.
- Raman spectroscopy reduces a manpower for analysis. (One person is enough to do analysis)
- Real time diagnosis of material.
- No sample preparation required.
- Can be analyse sample multiple time without destruction and same can be used for other test analysis.
- It can easily differentiate chemical structure even if they contain same atoms with different arrangement.
- Sample can be analysed through transparent polybag or container. No need to open container for scan.
- Almost all materials can be analysed.
6. Disadvantages of Raman spectroscopy
- Raman spectroscopy is very sensitive
- Quite costly equipment.
- Metal or alloy can not be used.
- Difficult to measure low concentrate on samples
- Sample heating through the laser radiation can destroy sample.
7. Difference between Raman spectroscopy and IR Spectroscopy
In Raman and IR spectroscopy some difference are there need to understand before conclusion.
- IR needs to prepare sample uniformly where as Raman spectroscopy can be scanned transparent container itself.
- FTIR is the difference of the two methods in dealing with interface. While in Raman spectroscopy fluorescence may interfere for taking spectra.
- Raman spectroscopy depends on change in polarizability of molecule whereas IR spectroscopy depends on change in dipole moment of molecule.
- Raman spectroscopy measures relative frequencies at which sample scatters radiation whereas IR spectroscopy measures absolute frequencies at which absorb radiation.
8. Types of Raman spectroscopy
There are major six types of Raman spectroscopy used in the industry.
- Spontaneous Raman Spectroscopy
- Resonance Raman Spectroscopy (RRS)
- Surface-Enhanced Raman Spectroscopy (SERS)
- Coherent Antistokes Raman Spectroscopy ( CARS)
- Stimulated Raman Spectroscopy (SRS)
- Partially offset Raman Spectroscopy (SORS)
Which light used in Raman spectroscopy?
Laser light is used in Raman spectroscopy. The source of light in Raman spectroscopy is Laser light.
9. Application of raman spectroscopy:
Raman spectroscopy has many application in different industries. It is a analytical research tool for the identification.
Raman spectroscopy application includes below industries.
- Pharmaceutical industry
- Forensic science Lab
- Planetary science
The Raman spectroscopy is widely used technique that has been adopted by many industries. In pharmaceutical industry it is used to determine the identification of the molecule.
As it is qualitatively it does give quantitative results. Some time this technique is used for quantitative analysis also.
I hope you understand the Raman spectroscopy uses advantages and disadvantages in the pharmaceutical industry.
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