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Every chemical compound deals with light uniquely. For example, some compounds reflect the light completely, some of them absorb it fully while some others absorb only a specific portion and reflect others.

As soon as the concentration of a chemical compound changes, its degree of light absorption or light transmission also changes. The spectrophotometer definition deals with the study of behavior of a compound with light gives us the qualitative and quantitative analysis of the compound.

The spectrophotometer function is used in biochemistry, chemistry, biology, physics, clinical studies, and many other fields of sciences. It enables the scientists to check the quality and quantity of the given sample, without getting in touch with them physically. The instrument that is used for this purpose is called a uv vis spectrophotometer.

Related: Read these articles to learn about standard gas laws and the law of thermodynamics.

What is a Spectrophotometer?

Spectrophotometer Definition

The spectrophotometer is an instrument that is used to perform an inexpensive and standard technique where light absorption or chemical concentration is measured. A spectrophotometer function usually consists of a few components including a light source, monochromator, sample chamber, detector, and a digital display. These instruments can be of two types as follows

  • Single Beam Spectrophotometer

    As the name indicates, this type of uv vis spectrophotometer uses a single light beam that could be either UV or Visible. While using this spectrometer, the intensity of light is being measured before and after the procedure. Such kinds of spectrophotometers are not only more compact but also come with a greater dynamic range.

  • Double Beam Spectrophotometer

    A double beam uv vis spectrophotometer also comes with a single light source. However, this light source is then split into two beams. One of these light rays passes through a reference solution while the second beam passes through the sample solution. Such spectrophotometers provide better precision and more automation features.

Related: Also learn about different instruments for splitting ions and spectral lines like capillary electrophoresis & nuclear magnetic resonance.

What is the purpose of Spectrophotometer absorbance?

The purpose of spectrophotometer absorbance is to measure how much light a substance absorbs. It help us to find the intensity of the light as a beam passes through a solution. The spectrophotometer principle for absorbance is to measure the molecules which absorb in an solution. Usually, the biomolecules absorb molecules at different wavelengths. It is not necessary that the wavelength of one specific molecule matches with the other.

The spectrophotometer absorbance is not only related to the measurement of molecules only. Infact, spectrophotometer principle allows it to absorb scattered light which did not passed through the detector. Furthermore, the chemical reaction also helps to measure the absorbance of the molecules.

How does a Spectrophotometer Work?

As the spectrophotometer definition indicates, whether you have a single beam spectrophotometer or a double beam one, the working method of both these types of instruments is nearly the same, with a slight distinction. Both types of instruments pass a beam of light through a chemical sample and record the result in the form of digital data.

The final result is studied in the form of absorbance readout which shows the number of absorbed photons. The general working procedure of a uv vis spectrophotometer is as follows

  1. First of all, a light beam emits from the light source. The source of light chosen depends upon the type of solution you are dealing with. However, the general light sources that are used during the procedure are UV, visible and infrared.
  2. This light then passes through a monochromator which disperses a polychromatic beam of light into a monochromatic one.
  3. After this, the monochromatic light is passed through the sample chamber where you have loaded the sample previously.
  4. After passing through the sample chamber, the light falls on the detector which could be any light-sensitive element. This detector then converts the light energy into electrical signals.
  5. The electrical signals are then shown at the digital display in the form of an absorbance readout.

Related: Read about periodic table and how to balance chemical equations, if you want to learn the basics of chemistry.

What does a Spectrophotometer Measure?

The spectrophotometer function is to measure transmittance (T) and absorbance (A) of light. To calculate the degree of transmittance, we used the spectrophotometer equation, given below

Transmission = It/I0

Here, It represents the intensity of light after passing the sample chamber while the I0 denotes the light intensity before crossing the sample chamber.

According to the beer-Lambert law, the amount or intensity of light that is absorbed by the sample solution is directly proportional to the sample concentration. Thus, measuring the concentration of solvent and solute in a solution is also a spectrophotometer function.

What are Spectrophotometers Used for?

The technique of spectrophotometry is widely being used in industry, science, and even in manufacturing units. Let's have a look at some of the applications of spectrophotometers in daily life.

  • Water Analysis

    It's mainly the water quality upon which the end products of an industry or manufacturing unit depend. However, analyzing the quality of water without using some chemical reaction techniques is extremely difficult.

    Related: Learning of metal displacement reaction in an aqueous solution as well as why DNA is a double helix.

    Fortunately, we have spectrophotometers that can measure the water quality in a few minutes, in a non-destructive way. The results provide us with detailed data about water clarity, purity, contamination of heavy metals, the concentration of pollutants etc.

    Related: Also learn about the conversion factor and factors affect the rate of reaction & line spectrum of hydrogen.

  • Uses of Spectrophotometer in Pharmaceutical Field and Pharmaceutical Industry

    The uses of spectrophotometer in pharmaceutical field are extensive. The process of manufacturing medicines requires extremely careful monitoring. It is because even a single, unnoticeable mistake can end up threatening the lives of so many people out there.

    By using spectrophotometer definition concept, we get effective and quick data of intermediates, raw material, and final product after a thorough quality control testing. Doing such thorough testing ensures whether you have prepared exactly what you want or not.

    Also, it tells us whether the resulting compound is pure or has some sort of impurities. Since a very minor quantity of sample is required to perform QC testing via uv vis spectrophotometer, it acts as a cost-effective way to ensure quality.

Frequently Asked Questions

Can Spectrophotometer measure fluorescence?

A spectrophotometer has the capability to measure fluorescence. Fluorescence spectrometers excites the fluorophore molecules and this makes scientists to measure the emitted fluorescence with UV light like a laser.

Can Spectrophotometer identify compounds?

Spectrophotometer can identify both organic and inorganic compounds. UV spectrophotometry is used to qualitative analysis of organic compounds.

Can Spectrophotometer measure rate of photosynthesis?

The spectrophotometer measure rate of photosynthesis in terms of light transmittance over time. Spectrophotometer measure the percentage of each wavelength of light absorbed by a pigment.

Can Spectrophotometer measure absorbance?

A spectrophotometer can measure absorbance by shining light of a specified wavelength through a sample. This makes it to measures the amount of light or the intensity of light that a sample absorbs.

Can a Spectrophotometer measure turbidity?

A spectrophotometer in transmission mode can measure the degree of turbidity from the amount of light scattered by the materials.

Why Spectrophotometer is preferred over colorimeter?

Spectrophotometer is preferred over colorimeter because of its high precision and increased versatility. Althouh it is expensive but determining the spectral reflectance at each wavelength makes spectrophotometer "The Winner".

What are the three main components of a Spectrophotometer?

The three main components of a spectrophotometer include light (as source), optics (to collect and deliver light) and a detector.

Why do Spectrophotometer need to be calibrated?

Spectrophotometer need to be calibrated so that it would continue to perform efficiently. Calibration ensures that the results are accurate and spectrophotometer has no issue related to its working.

We hope you liked our blogs. You can also use our mass percent calculator on the home page of this website. Moreover, find more useful blogs in the blogs section for enhance your knowledge in science like what is what is synthesis in chemistry as well as how to balance complex chemical equations.