What Is Raman Spectroscopy Used For?

Raman Spectroscopy

Raman spectroscopy is a spectroscopic and analytical laboratory technique used to detect the vibrational, rotational and other states in a molecular system. It is a non-destructive chemical analysis technique used to offer detailed information regarding the chemical structure.

The application fields, in which Raman spectroscopy is used are vast. The article takes you to the various areas where Raman spectroscopy is used and valued better.

Uses of Raman Spectroscopy

There are a plethora of areas where Raman spectroscopy is used. They are mentioned as follows:

• Pharmaceuticals
• Cosmetics
• Geology
• Mineralogy
• Carbon materials
• Semiconductors
• Life sciences
• Transmission
• Optoelectronics
• Polymers
• Materials
• Nanomaterials
• In situ analysis
• Geology
• Forensics
• Food & beverage
• Environment
• Energy
• Corrosion
• Catalysis
• Biology
• AFM
• Art & museums

Biology

The Raman spectroscopy technique provides label free characterization of biochemistry with sub-micron optimal resolution. It is an utility in the areas of:

• Detection of disease
• Cell research
• Drug design and pharmaceutical materials
• Microbiology and cell-sorting
• Cosmetics and in vivo skin analysis
• Stents and implants
• Characterisation of drug-cell interactions
• Metabolic accretions
• Photodynamic therapy
• Bone structure
• DNA and RNA analyses

The following are the specific applications in biology:

• SERS (Surface Enhanced Raman Spectroscopy) analysis of single living lymphocytes
• Analysis of single bacterium cell
• Mapping of wheat grain kernel
• In vivo measurement of human skin
• High resolution SERS details thrombosis mechanism
• SERS for intracellular imaging
• Sperm nuclear DNA integrity
• Raman Spectroscopy imaging of Monkey brain tissue 
• Investigation of microbes on a single cell level
• Investigation of atherosclerosis process through monitoring of cholesterol and free fatty acids
• In solid media, direct identification of clinically relevant microorganisms.

Art & Museums

• Raman spectroscopy is utilized in art and museums for the following purposes:
• Non-destructive and in-situ analysis of pigments
• Archaeometric analysis of ancient pottery
• Micro raman pigment analysis of wall paintings in church

Tip Enhanced Optical Spectroscopy (TEOS) & Tip Enhanced Raman Scattering (TERS)

• Characterization of molybdenum disulfide flakes using TEOS
• Characterization of carbon nanotubes using TERS
• Characterization of graphene raman spectrum using TERS

Carbon

• Raman spectroscopy is used in the following sectors related to carbon:
• Important forms of elemental carbon
• Raman spectra of hard carbon films used for derivation of physical parameters
• Information on carbon nanotubes like purity, electrical properties, 
• Colored diamond investigation
• Raman spectroscopy of graphene

Catalysis

In situ characterization of heterogeneous catalytic reactions

Corrosion

Observation of oxidation kinetics on aluminium alloy surface with fluorescence mapping

Cosmetics

Raman mapping utilized in investigation of soap compound

Energy

Lithium-ion battery analysis

Environment

• Identification of air borne pollen
• Statistical, Morphological and chemical depiction of particles on cellulose nitrate filters in quality control
• Confocal Raman spectroscopy imaging with amalgamation of chemometric methods for environmental applications

Food & Beverage

• Determination of composition of food and beverages via quantitative analysis
• Adulteration and bacterial contamination in quality control
• Identification of undesired materials or impurities
• Raman spectroscopy is not sensitive to high water content, hence suitable for analyzing aqueous solutions
• Raman spectroscopy examines powders, liquids and solids in different geometries, providing spectroscopic data and assesses the quality of translucent powders
• Micro Raman spectroscopy is used to assess the distribution of grains and particles within powders at the micrometer level.
• SERS aids in detection of trace organic compounds in ppm levels.
• Determination of fat and oil compositions
• Adulteration of oil
• Detection and recognition of bacteria and other microbes
• Analysis of carotenoids
• Melamine detection in milk
• Structural characterization of crops and grains
• Quantitative analysis

Forensics

• Detection of explosive materials
• For forged document investigation via sequence of non-intersecting lines
• Non-destructive and in-situ analysis of various black inks
• in-situ and non-destructive identifying of controlled drugs and narcotics

Geology and mineralogy

• Geological materials analysis
• Mineral and gemstone identification
• Fluid inclusions
• Phase and rock distribution in rock sections
• Phase transitions
• Behavior of mineral under extreme conditions

In situ Reaction Monitoring

• Microscopic measurement of diffusion
• Raman analysis in microreactor channels
• Study of lithium battery
• Online application in phosphorus chemical industry
• On-line monitoring of chemical products
• Real-time monitoring of polymerizations in emulsions via modelling and chemometrics

Solid State Materials

• Integrated circuits
• Laser-processed gas materials
• Inspection of solid state chemical reactions in composite materials

Nanomaterials

• Identification of materials constituting nanostructures
• Number of layers in graphene
• Number of layers in transition metal dichalcogenide monolayers (TMDC)
• Diameter and chirality of carbon nanotubes
• Stress and strain characterization
• Electronic properties of metallic, semiconductor and doping materials
• Localization of separated quantum dots and carbon nanotubes
• TERS provide chemical information
• Raman spectroscopy with Scanning probe microscopy (SPM) provide nanometer spatial resolution

Optoelectronics

• Three dimensional Raman imaging is used

Polymers

• Quantitative forecast of physical and chemical properties of polymers
• Localisation of polymeric phases of a laminated film
• Raman characterization of industrially used polymers
• Raman imaging of holographic gratings on polymer thin films
• Concentration profile measurements in polymeric coatings

Pharmaceuticals

There are so many usage exist for Raman spectroscopy in the field of pharmaceuticals:

• High-throughput screening
• Study of interactions of drug-like interactions with a target
• Determination of absolute configuration of lead compound or new molecules
• Understanding of activity of lead compounds and their optimization
• Crystalline behavior of the lead compound
• Identification of raw material
• Polymorphism and solid state studies
• Characterization of excipients and actives
• Distribution of compounds in tablets
• Troubleshooting
• In-process controls
• Monitoring of chemical and physical attributes like uniformity of content, distribution of compounds, thickness of coating
• Counterfeit detection
• Blend uniformity
• Verification of raw material
• Concentration of active pharmaceutical ingredient (API)
• Purity of powder content
• Combinatorial chemistry

The objectives fulfilled by the Raman spectroscopy include:

• Identification and validation of biological mechanisms behind the target or disease
• Identification of active molecules in the target
• Selection of candidate drugs and optimized properties for future developments
• Preclinical trials to document the safety of compound to enter into human trials
• Science of development, formulation and manufacturing of final drug product
• Ensuring the quality of durg and reduction of irrelevant products
• Defense of intellectual property
• Study of generics
• Fight against marketing of counterfeit

Semiconductors

• Raman imaging of of single gallium nitride nanowire
• Detection of strained silicon in MOSFETs
• Strain assessment in Si cap layer, which is deposited on a SiGe substrate
• Determination of Ge content in SiGe substrate

Conclusion

The use of Raman spectroscopy and its types are innumerable. Compared to UV-Vis spectroscopy, it has more sensitive usage, which is extremely important for the production of various industries.