What is a Spectrophotometer? - Principle, Types, Uses, and Benefits

Reviewed by Anurag Mishra (Sr. Technical Consultant)

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In the world of colors, the spectrophotometer TP 800 is commonly used equipment. A spectrophotometer is a color analysis device that is used in most laboratories and industries to measure the absorbance offered by a chemical solution when light passes through it.

spectrophotometer TP 800

Portable spectrophotometer can be used for analyzing the concentration of the primary colors in the solution that contribute to its overall appearance. Every color absorbs a certain wavelength of light, and a certain wavelength of light is transmitted or reflected by the same solution. The procedure of light absorption can be used for the purpose of determining the chemical substance as well.

Working principle of Portable Spectrophotometer

The working principle of a spectrophotometer is based on Beer’s Law, or Beer-Lambert’s Law which can be expressed as the amount of light absorbed by a solution is directly proportional to the concentration of the solution. A photodetector used in the spectrophotometer captures the transmitted light, measuring its intensity. The decrease in light intensity compared to the initial beam corresponds to the sample's absorbance. The mathematical expression for Beer’s Law can be given as

A = εlc

Where A is the absorbance of the solution or sample, ε is the molar extinction coefficient or molar absorptivity or absorption coefficient is the path length and c is the concentration of the solution. The absorption coefficient is constant for a given chemical solution, and it can vary with every molecule. You can read more about what does spectrophotometer measures.

Spectrophotometer Principle – The principle of a spectrophotometer is based on the Beer-Lambert Law which states that the light absorbance of a substance is proportional to its concentration and path length of light through the sample. It determines how much light a sample absorbs at a specific wavelength by comparing the intensity of the incident light to the transmitted light, enabling both quantitative and qualitative analysis.

Types of Spectrophotometers

Different spectrophotometers exist with different functionalities, such as UV-vis, Infrared, Fluorescence, and Atomic Absorption, among others. They are important in science fields like chemistry, biology, and material science regarding the analysis of properties and concentration of materials. Here is a more detailed explanation of the types of spectrophotometers:

UV-Visible Spectrophotometer

This type measures light in the ultraviolet and visible regions of the electromagnetic spectrum (typically 200-800 nm). It is widely used in chemistry and biochemistry to analyze the absorption spectra of compounds, identify substances, and determine concentrations.

Infrared (IR) Spectrophotometer

IR spectrophotometers measure absorption in infrared light, ranging from 700 nm to 1 mm. The main applications of these instruments are in chemical and material analyses, which take advantage of molecular bond-specific absorption of certain infrared wavelengths by different molecules to identify functional groups and study molecular structures.

Fluorescence Spectrophotometer

This spectrophotometer measures fluorescence emitted by a sample when it absorbs light at one wavelength. It is the most sensitive tool used in trace-level analysis in biochemistry, molecular biology, and environmental analysis.

Atomic Absorption Spectrophotometer (AAS)

AAS is used to detect metals and some non-metals in a sample by measuring the absorption of light at specific wavelengths. It is highly effective in environmental testing, agriculture, and quality control of food and beverages for heavy metal content.

Double-Beam Spectrophotometer

This type features two light paths—one for the sample and another for the reference. It helps compensate for fluctuations in light intensity, providing more accurate and stable measurements, and making it suitable for high-precision applications in laboratories and research.

Nuclear Magnetic Resonance (NMR) Spectrophotometer

Not exactly a spectrophotometer in the classical definition, but NMR spectrometers measure the interaction of nuclear spins with magnetic fields to obtain information on molecular structures, especially in organic chemistry and pharmaceutical research.

Raman Spectrophotometer

Raman Spectrophotometer takes its basic principles of investigations regarding chemical nature from Raman spectroscopy. It works without requiring sample preparation, unlike infrared spectrophotometry, to gain details about molecular structures. A Raman spectrophotometer is applied in material science, the fields of chemistry, and pharmaceutical analysis.

There are two instruments used in a spectrophotometer that is spectrometer that is used for creating the desired wavelength of light and the photometer which is used for measuring the intensity of transmitted light.

Portable Spectrophotometer

The instruments are designed in such a way that the liquid is placed in a cuvette which lies between the spectrometer and the photometer. When the spectrometer sends a beam of light to the liquid, the liquid absorbs some part of the beam and rest is transmitted to the photometer which then measures the intensity of the transmitted light. Color analysis made easy with this portable spectrophotometer.

Uses of Portable Spectrophotometer

The portable spectrophotometer is used in various industries including Pharmaceutical, food and beverage, chemical, material science, cosmetics, etc. More precisely, it is employed in fields such as environmental monitoring to measure water quality, in agriculture for soil and plant analysis, and in food and beverage testing to assess nutrient or contaminant levels. Some of the materials that are tested through spectrophotometers are as follows –

  • They can be used for measuring the concentration of the chemical compounds and solutions that are used for different experiments in laboratories.
  • The spectrophotometers can be used for measuring the color concentration in different food ingredients and food products.

spectrophotometers

  • The instrument is also used for testing the colors intensity of textile materials and products to ensure that the best processing of such materials.

Testronix offers highly efficient and accurate spectrophotometers that have been used in many different industries to ensure the best color quality of products. TP 800 portable spectrophotometer offers a high rate of repeatability with very little scope for errors between two measurements.

Benefits of using Portable Spectrophotometer TP 800

The spectrophotometer is equipped with dual viewing angles of the specimen that allow the operator a crystal clear vision for precise and accurate assessment of the specimen.

The instrument offers a homogenous ray of lights which enable the operator to perform testing under variable atmospheric illumination. For ex. D-65 lightening atmosphere.

The reflectance of the light rays can be adjusted to a 45o angle, allowing the specimen to align with the light rays, and assisting the manufacturer to evaluate the color tonality with a lot more precision.

using Portable Spectrophotometer

The instrument offers a reflectance curve of 400-700nm which is designed to comply with a human’s visionary standards. This enhances the accuracy of the operator performing the task.

The SQT8 software of the device promotes single-handed operations without any hassle at all and also enables the tracking of results with absolute facile.

The instrument’s operator-friendly features enhance the repeatability of testing. Features like capacitive buttons along with a touchscreen to perform testing with ease and derive desired results. You can read more on the benefits of portable spectrophotometer.

How does the spectrophotometer work?

The Spectrophotometer is a lab testing instrument designed to function under an ambient atmosphere that does not range above or less than the humidity levels of 30% to 95%.

The instrument is turned on with the help of a power switch associated with the right side. After pressing the switch button, you can see the digital LCD screen turn on.

The instrument will depict white & black calibration as per the required standards of the designated testing standard. After selecting the white calibration option, the operator can simply place the measuring aperture above the whiteboard.

Once the measuring aperture is precisely positioned, the operator can press the ‘ok’ / ‘testing’ button to start the white calibration of the specimen being tested.

Similarly, the black calibration is performed by the operator to eradicate the black cavity.

After performing both calibrations, the operator can simply profile the specimen as per the required standards. After profiling the sample according to the designated standards, the operator can press the ‘Sample measure’ button.

spectrophotometer work

The LCD screen will depict the L* a* b* C* h* data on the left side as the data of the current sample and similar data indicating the color difference between the current sample and the standard sample.

This is how the spectrophotometer enables single-handed testing of colored specimens with absolute facile and no hassle at all. If you want to know more about this testing instrument then you can give us a call at +91 9313 140 140 or email us at info@testronixinstruments.com.

Frequently Asked Questions

Types of samples that can be tested using a spectrophotometer

Spectrophotometers can analyze a wide range of samples, such as liquids, solids, and gases, making them versatile for various fields. Common samples are biological fluids, such as blood, serum, or urine, for clinical analysis and water samples for environmental testing. Also, it is used to test chemical solutions in research and the concentration of certain compounds, such as sugars or proteins in the food industry. Apart from this, solid materials in the form of thin films, powders, or coatings can be analyzed for their optical properties. Another area where spectrophotometers play a significant role is in material sciences in the measurement of light absorption and reflectance of different substrates including metals and polymers.

What is the Spectrophotometer Principle?

The principle of a spectrophotometer is based on the Beer-Lambert Law, which describes the relationship between the absorbance of light by a sample and the concentration of the absorbing substance. When light passes through a sample, some wavelengths are absorbed by the material, while others pass through.

The spectrophotometer measures the amount of light absorbed at specific wavelengths and calculates the sample's absorbance. This absorbance is directly proportional to the concentration of the substance being tested, assuming a constant path length.

To measure absorbance, the spectrophotometer emits light from a stable light source through the sample, which may absorb some of the light. The remaining light is detected by a photodetector, which compares the incident light to the transmitted light. The resulting data is then used to quantify the concentration of the substance in the sample.

How do you calibrate a spectrophotometer?

Calibrating a spectrophotometer is crucial for accurate measurements and reliability of results. The process typically involves using a blank sample, which contains all components of the test solution except the substance being measured.

The spectrophotometer is powered on in the first step, and the blank sample is placed in the sample holder. The instrument is then adjusted to zero absorbance or 100% transmittance, ensuring that it reads no absorption for the blank. Next, a standard solution, known as the concentration of the analyte is used to verify the accuracy of the device across a range of wavelengths. The spectrophotometer is recalibrated if discrepancies are observed.

What industries can use a Spectrophotometer?

Spectrophotometers are widely used in different industries to measure the absorption of light and quantify the concentration of substances in various types of samples. The key industries that rely on spectrophotometry include –

  • Pharmaceutical and Healthcare: It is frequently used in drug development, clinical diagnostics, and medical research for the analysis of blood, urine, and other biological fluids for disease markers or drug concentrations.
  • Environmental Monitoring: Used to measure the quality of water and air and determine if there are pollutants or contaminants present, such as heavy metals or organic compounds.
  • Food and Beverage: Determine nutrient levels, preservatives, and contaminants in food products and are also used for quality control during production.
  • Chemical and Materials Science: In the lab, spectrophotometers measure the concentration of reagents and products so that formulations and reactions can be as accurate as possible.
  • Agriculture: Spectrophotometers are used for soil and crop testing to determine the nutrient content of soil or the health of plants based on their absorbance properties.
  • Cosmetics and Personal Care: It is used to test the formulation of products and ensure consistency, quality, and safety by analyzing ingredients and their interactions.
  • Forensic Science: It is applied in criminal investigations to analyze trace evidence, such as fibers, drugs, or bodily fluids, for criminal case analysis.

If you are in any of these industries, your business can take a revolutionary turn through the Spectrophometer TP-800. Book a free sample test today to match your colors with those of customers and increase customer satisfaction rates. Getting a clear idea of your sample will allow you to make error-free products and will rewind the rejections!

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