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What is UV-Vis Spectrophotometer, and how does it work?

UV-Vis Spectrophotometer

UV-visible (UV-Vis) Spectrophotometer is a widely utilized technique in many fields of science, including bacterial culture, drug identification, nucleic acid purity checks, and quantification, as well as beverage quality control and chemical research. This article will explain what UV-Vis Spectrophotometer, the technique’s advantages and disadvantages, and some of its uses is.

What is UV-Vis Spectrophotometer, and how does it work?

In comparing the two to a reference or blank sample, UV-Vis Spectrophotometer is an analytical method that analyses the number of distinct wavelengths of UV or visible light collected by or transmitted through a test. The sample composition influences this attribute, providing data on what is in the trial and concentration. Because this Spectrophotometer approach relies on light usage, they will begin with the quality of the light.

The energy quality is contained in light is inversely related to its wavelength. As an outcome, shorter light wavelengths carry more energy while longer wavelengths carry less. To boost electrons in a material to a higher energy state, which we can observe as absorbing power, a precise quantity of energy is required. In a substance, electrons in specific binding environments need varied energy to drive them to a higher energy state.

This is why various wavelengths of light are absorbed by different things. Humans can see a visible light spectrum ranging from 380 nanometers, which we perceive as violet, to 780 nanometers, which we perceive as red. UV light has wavelengths that are around 100 nanometers shorter than visible light. As a result, light may be defined by its wavelength, which can be helpful in UV-Vis Spectrophotometer for analyzing or identifying various compounds by locating the exact wavelengths that correlate to maximal absorbance (see the Applications of UV-Vis Spectrophotometer section).

UV-Vis Spectrophotometer’s Advantages and Limitations

There is nothing as a perfect procedure, and UV Vis Spectrophotometer is no exception. The approach does, however, offer a few key advantages that make it popular, which are stated below.

  • The method is non-destructive, enabling the sample to be recycled or processed, or analyzed further.
  • Measurements may be taken fast, making them straightforward to incorporate into experimental techniques.
  • Instruments are simple to operate and require little user training before usage.
  • In most cases, data analysis necessitates minimum processing, implying that little user training is necessary.
  • The instrument is relatively affordable to purchase and run, making it suitable for a wide range of laboratories.

Although the advantages of this strategy appear to be overwhelming, there are several drawbacks:

  • Stray Light:

Wavelength pickers are not ideal in practical instruments. A tiny amount of light from an extensive range of wavelengths may still be passed from the light source, potentially producing substantial measurement mistakes. Light from the outside or a loosely fitting compartment in the device might also cause stray light.

  • Light Scattering:

Suspended particulates in liquid samples induce light scattering, leading to substantial measurement mistakes. If there are bubbles in the cuvette or illustration, the light will scatter, resulting in inconsistent results.

  • Many absorbing species interferences:

A sample may include multiple kinds of the green pigment chlorophyll, for example. When the various chlorophylls are evaluated together in the same instance, their spectra overlap. Each chemical substance should be isolated from the sample and evaluated separately for a correct quantitative analysis.

  • Geometrical considerations:

If any of the instrument’s components, particularly the cuvette containing the sample, is misaligned, the findings can be unpredictable and erroneous. As a result, every element in the instrument must be oriented in the same direction and positioned in the exact location for each measurement. To avoid misuse, some formal user training is often recommended.

Application or practical use of UV-Vis Spectrophotometer

Analysis of beverages

A typical application of a UV-Vis Spectrophotometer is the identification of specific substances in beverages. Caffeine levels must be kept within particular legal limits, measured using UV light. Certain colored compounds, such as anthocyanin present in blueberries, raspberries, blackberries, and cherries, can be easily recognized in wine using UV-Vis absorbance by matching their known peak absorbance wavelengths.

Bacterial cultivation

In bacterial culture, UV-Vis Spectrophotometer is frequently utilized. To assess cell concentration and follow growth, OD measurements are often and swiftly conducted at a wavelength of 600 nm. Due to the optical properties of the bacterial culture conditions in which they are cultivated and to avoid injuring the cells in circumstances where they are necessary for continuing testing, 18 600 nm is widely employed and chosen.


From the above, it is clear that UV-Vis Spectrophotometer is a quantitative technique for determining how much light is absorbed by a chemical material. This is accomplished by comparing the intensity of light passing through a sample to that passing through a reference sample or blank



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