What Is Spectrometry And What Is It Used For?

01 Sep, 2016
What Is Spectrometry And What Is It Used For?

Spectrometry is the study of interactions between light and matter, and the reactions and measurements of radiation intensity and wavelength.

Far from being a specialised, unique field, spectroscopy is an integral element of the scientific process within a variety of disciplines. While it provided a theoretical backing to early quantum research in radiation and atomic structure, it also has a staggering number of other applied uses; Magnetic Resonance Imaging (MRI) and X-ray machines utilise a form of radio-frequency spectroscopy, we measure the unique makeup and physical properties of distant astral bodies through their spectra and wavelength, and it’s even used to test doping in sports!

Spectrometers – the chief instrument used in spectrometric analysis – are specialised pieces of equipment that measure radiation types and wavelength.

Modern spectrometry

The study of spectrometry dates back to the 1600s, when Isaac Newton first discovered that focusing a light through glass split it into the different colours of the rainbow (known as the spectrum of visible light). The spectrum itself is an obviously visible phenomenon; it’s makes up the colours of the rainbow and creates the sheen you’ll see on the surface of a puddle, but it took centuries of piecemeal research to develop the study of this phenomenon into a coherent field that could be used to draw usable conclusions.

Generations of work by scientists, such as William Hyde Wollaston, lead to the discovery of dark lines that were seemingly randomly placed along this spectrum. Eventually it was determined that these were the after-effects of absorption of chemicals in the earth’s atmosphere.

Simply put, as natural light filters from space from celestial bodies such as the sun, it goes through various reactions in our atmosphere. Each chemical element reacts slightly differently in this process, some visibly (those on the 390-700mm wavelength which detectable to the human eye) and some invisibly (like infrared or ultraviolet waves, which are outside the visible spectrum).

As each atom corresponds to and can be represented by an individual spectra, we can therefore use the analysis of wavelengths in the light spectrum to identify them, quantify physical properties, and analyse chemical chains and reactions from within their framework.

Some ways we use spectroscopy in a practical manner include:

  • In astronomy, we can use the unique spectra to identify the chemical makeup of objects in space.
  • We can also use it to identify properties about space objects: chiefly their temperature, as well as their velocity.
  • It has applications in metabolite screening and for analysing and improving the structure of drugs.
  • We can use it to measure sampled chemicals or nanoparticles through their mass-to-charge ratio (using a mass spectrometer).

Types of spectroscopy

There are multiple fields of spectroscopy. Some of the potential fields and applications include:

Mass Spectronomy

Sorts and measures masses within a chemical sample through their mass-to-charge ratio. This is usually done by ionizing the particles with a shower of electrons, then passing them through a magnetic field to separate them into different stages of deflection.

Once the particles are separated, they’re measured by an electron multiplier, and we can identify the makeup of the sample through the weight of each ion’s mass.

Practical uses of Mass Spectronomy include isotope dating and protein characterisation. Independant roving space exploration robots such as the Mars Phoenix Lander also carry mass spectrometers for analysis of foreign soils.

Astronomical Spectrometry

Chiefly concerned with the analysis of objects in space. From simple spectroscopic analysis of a body, we can determine their wavelength, which can then give us their chemical composition (as a factor of their spectra and mass), temperature, distance and speed (using a function of their wavelength and the speed of light).

Absorption Spectrometry

Involves the analysis of the absorption of radiation in matter in the electromagnetic spectrum.

Much like how the spectrum of solar light that filters through our atmosphere has Fraunhofer lines – bands that correspond to different elements that are blocked by our atmosphere – so too can we determine atomic makeups of a sample by testing for the absorption of specific elements.

Biomedical Spectroscopy

This is a great example of the multidisciplinary nature of spectroscopy. Magnetic resonance spectroscopy (a subset of MRI) is often used to diagnose and study chemical changes in the brain which can cause anything from depression to physical tumours, as well as analyse the metabolic structure of muscle.

This works by mapping a spectrum of wavelengths in the brain that correspond to the known spectrum, and carefully analysing patterns and aberrations in those patterns.

Energy Dispersive(EDS/EDX) X-ray spectroscopy

Energy Dispersive X-Ray spectroscopy (otherwise known as EDS/EDX) is another analytical technique which is used for the identification and quantification of elements found in a sample. It is also used by the desktop Phenom SEM series. This technique scan also be used in conjunction with Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM) and Scanning Transmission Electron Microscopy (STEM) to create spatially resolved elemental analysis in areas as small as a few nanometres in diameter.

Spectrometers

A spectrometer measures the wavelength and frequency of light, and allows us to identify and analyse the atoms in a sample we place within it.

In their simplest form, spectrometers act like a sophisticated form of diffraction, somewhat akin to the play of light that occurs when white light hits the tiny pits of a DVD or other compact disk.

Light is passed from a source (which has been made incandescent through heating) to a diffraction grating (much like an artificial Fraunhofer line) and onto a mirror. As the light emitted by the original source is characteristic of its atomic composure, diffracting and mirroring first disperses, then reflects, the wavelength into a format that we can detect and quantify.

ATA Scientific stocks and specialises in JASCO spectroscopic equipment through our subsidiary Labsavers. We stock a range of Ultraviolet-visible Spectrophotometers, Fourier Transform Infrared Spectrometers, Fluorescence Spectrometers, Circular Dichroism Spectrometers, Raman Spectrometers, and Digital Polarimeters.

The entire line of JASCO spectrometers all utilise a central operating system, Spectra Manager. This means that they easily standardise operations between different processes, are easy to use, and are usually able to be self-installed. We have options for both laboratory and teaching environments at competitive prices, and everything comes with a 12 month warranty.

No matter what kind of laboratory you need it for, if you’re in the market for spectroscopic equipment you can’t beat our range of JASCO equipment.