Spectrometer and Spectrophotometer

Small molecules combine to form a certain material. These molecules have atoms with electrons in them. When the energy is absorbed by the particle, the electrons in the molecules get excited. Such molecular interactions can be easily identified like sparks in certain metals. Such sparks created by the electromagnetic waves form visible light on the visible spectrum.

Studying these interactions between matter and light produces the measurement of the light spectrum and these measurements are accomplished with different techniques. Spectroscopy and spectrophotometry is the commonly used term in the study of light spectrum interactions. 

Spectroscopy is the study of light spectrum interaction with the matter theoretically, on the other hand, spectrometry is the instrument that produces light to interact with the sample and measure the light spectrum after passing through the sample.

Spectrometry is an instrument that allows doing quantitative and qualitative analyses of samples with the absorption characteristics of the sample. Spectrometers differ from spectrophotometers. Researchers use the spectrometer to collect information on the sample substance based on the visible, UV or infrared light that it projects and is used in various fields of science.

It is clear that the familiarity between the two devices spectroscopy and spectrometry is that both are used for the study of light interaction with matter using different techniques. Now let’s see the difference between spectroscopy and spectrometry.

What is Spectroscopy?

Spectroscopy is the term used to study the absorption and emission characteristics of matter theoretically when exposed to the light spectrum of electromagnetic radiation or other radiation. It is generally expressed as the interaction between electrons, protons, and ions.

Huge scientific research was developed theoretically using spectroscopy. It plays important role in the development of various fields like life science, biotechnology, physics, chemistry, and even astronomy. Since these studies are made theoretically no actual results are obtained.

Spectroscopy is used in a wide range of techniques in various fields. Some of them are as follows,

  • Absorption spectroscopy
  • Infrared spectroscopy
  • UV spectroscopy
  • X-ray spectroscopy
  • Laser spectroscopy
  • Raman spectroscopy

Absorption Spectroscopy

Absorption spectroscopy is the method in which the sample absorbs light with respect to the wavelength. The molecules of the sample absorb the light and get excited. The amount at which the electrons in the molecule are excited is proportional to the wavelength of the light.

Infrared Spectroscopy

Infrared spectroscopy measures the interaction of interatomic bonds of a sample. This spectroscopy uses infrared radiation as a light source and is measured at different frequencies. Infrared spectrometers are used for the measurement of the number of absorbing molecules.

Ultraviolet or UV spectroscopy

In UV spectroscopy, the sample is exposed to the ultraviolet light source. Once the sample is exposed to the UV light source, the electrons get excited and the absorbance characteristics of the sample are measured based on the excitation. This type of spectroscopy is used to determine the chemical bonding of molecules.

X-ray spectroscopy

When the electron in the sample molecules is excited, holes are created resulting in energy absorption, which produces an x-ray fluorescence emission spectrum.

Laser spectroscopy

Laser spectroscopy in which a laser is used as a light source of radiation. This spectroscopy has higher sensitivity and higher resolution. This spectroscopy measures interaction of laser radiation with the sample molecules.

Spectroscopy is widely used in various fields. It helps not only to do fundamental analysis and fundamental theories of physics but also helped researchers to better understand the electromagnetic and nuclear forces.

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What is Spectrometry?

Spectrometry is the application of spectroscopy that deals with the actual quantitative measurement of a specific spectrum. Spectrometry is required to analyze and interpret spectroscopy.

What is Spectrometer?

A spectrometer is an instrument that uses various techniques to measure the variation of physical characteristics of the spectrum using spectrometry.

The spectrometer is the best tool that is used to collect information about a material based on the amount of light radiation it can be either infrared, visible, or ultraviolet light. Astronomers use spectrometers for various purposes to determine the weight of objects, speed of the objects, and temperature of those objects.

Spectrometers also help to determine the different compositions of items. In the medical field, spectrometers are commonly used to determine toxins, contaminants in the bloodstream, doping in sports, and also to find disease markers.

Likewise, spectrometers have a wide range of applications in various fields. Some of the major applications are listed below:

  • In the marine ecosystem it is used to monitor the dissolved oxygen content 
  • Characterization of protein
  • Study of spectral emission lines of distant galaxies.
  • Respiratory gas analysis in hospitals 
  • Space exploration 

What is a Spectrophotometer?

It is crucial to understand the difference between spectrophotometry and spectrometry. Spectrophotometry measures the absorbance of light by specific chemical substances. The spectrophotometer is an instrument that is used to apply spectrophotometry.

Principle of spectrophotometer

Depending on the applications different types of spectrophotometers. Such that the exact definition also varies depending on the different fields of science or industry. The term “photo” indicates light. The spectrophotometer is a spectrometer that is used to quantitatively measure light intensity with specific wavelengths.

The spectrophotometer measures the light absorbance, transmittance, and reflectance of a sample for a specific wavelength. The diffusivity of light in the electromagnetic spectrum in the range of 200 nm to 2500nm is measured using different calibrations and controls.

Types of Spectrophotometers

Generally, there are two basic types of spectrophotometers, single-beam spectrophotometer, and double beam spectrophotometer. A single beam spectrophotometer measures the relative light intensity of the sample and reference sample separately. 

In the case of a double beam spectrophotometer, it measures the light intensity of the sample and reference simultaneously. It also compares the light intensity and measures the absorption of light by the sample.

Other types of spectrophotometers include,

  • Atomic Absorption Spectrophotometer
  • Infrared Spectrophotometer
  • Colorimeter
  • Spectrofluorometer


The spectrometer is a part of a spectrophotometer that is used to measure a specific spectrum. Apart from the spectrometer, a spectrophotometer also includes a light source and a detector to detect the light spectrum that has interacted with the samples. Generally, all spectrophotometers incorporate spectrometers. Other analytical instruments also use spectrometers.

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