Spectrometer Technology and Applications

By Kris WalkerOct 31 2013

A spectrometer is a device for measuring wavelengths of light over a wide range of the electromagnetic spectrum. It is widely used for spectroscopic analysis of sample materials.

The incident light from the light source can be transmitted, absorbed or reflected through the sample. The changes occurred during the interaction of incident light with the sample reveals the sample characteristics.

Two types of radiation sources are generally employed in spectrometer – continuous and line sources. Continuous sources are heated solid substances or lamps that emit light over a wide wavelength range, and line sources are specialized lamps and lasers.

Incident light can be adjusted to the wavelength of interest with the help of dispersive or non-dispersive elements.

Uses of Spectrometer

Some of the major applications of spectrometers include the following:

• Monitoring dissolved oxygen content in freshwater and marine ecosystems
• Studying spectral emission lines of distant galaxies
• Characterization of proteins
• Space exploration
• Respiratory gas analysis in hospitals

Mass Spectrometry

A mass spectrometer is a device that measures the mass and concentration of individual molecules and atoms by producing spectra.

These spectra can be used to investigate elements, masses, isotopes and chemical structures of the sample materials.

Mass spectrometers are operated by calculating the mass-to charge ratios of molecular fragments or charged molecules generated due to the ionization of chemical compounds.

The selection of charged particles of a specific velocity is carried out by using a velocity selector. The selector works by comparing the magnetic and electric forces with respect to the speed of specific particle.

The issue of not being able to not travel to distant planets with ease would seem to halt space exploration in terms of finding out which type of molecules are in a particular sample. The solution for space exploration is through using mass spectrometers which are used to identify miniature particles present in space.

Mass spectrometers are also used in radioactive and carbon dating. When used with gas chromatographs, mass spectrometers detect traces of toxic particles and contaminants in air.

Used for measuring wavelengths, spectrometers are used in many applications.

Types of Spectroscopy

The following are some of the major types of spectrometers:

Absorption Spectroscopy

This method of spectroscopy works by absorbing light with respect to the wavelength. The sample molecules are excited to a higher energy state upon absorbing the incident light. The excitation is directly proportional to the wavelength of light.

Infrared Spectroscopy

Infrared Spectroscopy measures the vibrations of inter atomic bonds of a sample at different frequencies when the sample is exposed to infrared light. Infrared spectrometers can also be used to measure the number of absorbing molecules.

X-ray Spectroscopy

This works by exciting the inner electrons of sample molecules. When the excited electrons fall into the vacancy generated due to energy absorption, an x-ray fluorescence emission spectrum is produced.

Ultraviolet Spectroscopy

In this method of spectroscopy, the sample is exposed to ultraviolet light. Electrons are excited upon absorbing light energy. The absorbance characteristics of the sample are measured based on the excitation of electrons. This type of spectroscopy can be used to investigate chemical bonding of sample molecules.

Laser Spectroscopy

Laser spectroscopy uses 'laser light' as a radiation source. It can be used to measure the interaction of light with sample molecules. This spectroscopy has high sensitivity and resolution.

Spectrometer Smartphones could be incorporated into a host of applications.

Smartphone Spectrometer

Today, different types of medical instruments from eye testing machines to ultrasound probes are incorporated within smartphone technology. One of the recent developments in this arena is an iPhone™ cradle discovered by researchers from the University of Illinois.

The device uses a series of optical parts and the phone’s camera to detect the light passing via the sample liquid. Light spectrum, is then compared with the spectra for target molecules such as bacteria or toxins so as to determine the characteristics of the sample.

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Further Reading: Spectrometer – UCDAVIS CHEMWiki , Mass Spectrometer – Georgia State University ,  A Smartphone Spectrometer Diagnoses Disease At A Fraction Of The Price – Fast Co.Exist

Image Credit: Photos.com

NASA| The Molecule Dissector - Mass Spectrometry Run Time: 2.26mins