Molecular Spectroscopy Instruments: How They are Used in Scientific Research

With the improvements in scientific research come different molecular spectroscopy instruments to aid in methodologies, helping scientists and researchers better analytical tools and equipment. By measuring the energy and frequencies of light that molecules emit, these instruments can provide valuable information about the structure and composition of molecules. 

This blog post will look at how molecular spectroscopy instruments are used in scientific research and what benefits they provide. We will also explore some of the most common molecular spectroscopy instruments.

What is Molecular Spectroscopy

Molecular spectroscopy is a spectroscopic technology used to measure interactions between matter and electromagnetic waves. This analytical field is used in several types of research, commercial, academic, and government laboratories, helping determine a specific material’s composition. 

Instruments Used in Molecular Spectroscopy

Today, many innovative machines have started to get involved in molecular spectroscopy, improving its efficiency and effectiveness in analysis and chemical composition determination. Let’s talk about them and how you can use them in scientific research. 

UV-Vis Spectrometers

UV-Vis spectrometer is an analytical instrument that measures how much a specific chemical substance absorbs visible or UV light. It does this by measuring how much light intensity passes through a certain sample and comparing it with a reference or a black sample. The light intensity is measured in wavelengths. 

One of the benefits of this instrument is its versatility in molecular spectroscopy. It can examine liquid, glass, and even thin films. A UV-Vis spectrometer is an innovative instrument that can see beyond our naked eyes, including infrared and ultraviolet light. 


UV-Vis spectrometers consist of four essential components: a light source, a wavelength selector, a sample container, and detectors. Generally, the light sources used in this instrument are xenon lamps, tungsten lamps, deuterium lamps, and halogens. 

A wavelength selector is used to determine the wavelength type that suits the analyte and sample, allowing sample examinations to be taken from the wavelengths emitted by the light source. The most common type widely used in scientific research is a monochromator, and it contains the parts listed below:

  • Entrance slit
  • Dispersing device (prism or a grating)
  • Collimating lens
  • Focusing lens
  • An exit slit

The sample container is recommended to be transparent, and quartz cuvettes or fused silica are the commonly used materials. The most commonly used UV-Vis spectrometer detector is the photomultiplier tube, containing a photoemissive cathode, an anode, and dynodes. 

Scientific Research Application

UV-Vis Spectrometers are mainly used in DNA and RNA analysis, verifying their concentrations and maintaining their purity. They are also famous for culturing bacteria, tracking their growth, and estimating cell concentrations. Generally, 600 nanometers are the wavelength measurement used for the preservation of bacterial culture media. 

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FTIR Spectroscopy Instrument

FTIR spectroscopy instruments are another famous molecular spectroscopy instrument used for organic, inorganic, and polymeric material identifications. These instruments utilize FTIR analysis and infrared light for scanning test samples, observing, and researching their chemical properties. 

Many researchers prefer this instrument because it allows various chemical substances and molecules to produce certain spectral fingerprints. FTIR spectroscopy instruments mainly convert the output from the detector into spectrums, interpreting and formulating patterned spectra. 


An FTIR spectroscopy instrument has three main components: the light source, the interferometer, and the detector. Light sources typically used in these instruments are broadband emitters with either a mid-IR ceramic source, a near-IR halogen lamp, or a far-IR mercury lamp. 

For this instrument’s interferometer, the inspiration is the Michelson Experimental Setup. The interferometer consists of a beam splitter and two mirrors with one fixed and the other translating back and forth. Afterwhich, the beam will enter the detector that converts it to photons converted into electrical signals that a computer will read. 

Scientific Research Application

FTIR spectroscopy instruments are widely used to identify and characterize materials in research, such as powders, films, solids, and liquids. They can also identify any presence of contamination and additives after extracting a polymer matrix. Other applications of FTIR spectroscopy instruments in scientific research are the following:

1. Determining uncured monomers, decomposition, and oxidation in failure analysis investigations

2. Gaining kinetic information on an infrared absorption’s decay or growth. 

Fluorescent Spectrometer 

Fluorescent spectrometers are mainly used in the detection and analysis of organic compounds. They are commonly placed in environmental science and chemistry laboratories, measuring a molecule’s fluorescence and gathering information about its corresponding composition and chemical environment. 

There are two main types of fluorescent spectrometers:

1. Filter fluorometers for filtering and isolating different light sources

2. Spectroflurometers for isolating light sources containing diffraction grating monochromators


The main components of a fluorescence spectrometer are an excitation monochromator, white light source, emission monochromator, sample chamber, and detector. 

Scientific Research Application

Fluorescence spectroscopy in the medical field is becoming more common for various purposes. It has been shown to have high sensitivity with specificity when diagnosing microorganisms-associated diseases through spectroscopic fingerprints.

Molecular Spectroscopy Is The Future

Molecular spectroscopy makes everything easier – from scientific research to more practical applications. With the instruments mentioned above, you’re guaranteed to perform accurate molecular analyses with fewer machine mistakes and human error. 

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