Colorimeter | Optical Sensors

Summary

Optical sensors convert light interactions into electrical signals to detect physical or chemical properties of substances. Colorimetric sensors, operating in the visible spectrum, determine the concentration of colored chemical species by measuring light absorption according to Lambert's law. The setup includes a light source, lens, filter for monochromatic light, a sample holder, and a photodetector that amplifies the signal for display. Applications span biomedical analysis, environmental monitoring for heavy metals, and agricultural product testing, highlighting the versatility of colorimetric sensors.

Takeaways

• 🌟 Optical sensors convert light interactions into electrical signals to detect physical or chemical properties of a substance.
• 🔬 Colorimetric sensors are a type of optical sensor that operates in the visible light spectrum (400 to 800 nanometers) and are used to determine the concentration of colored chemical species.
• 📚 Lambert's law states that the absorbance of light is directly proportional to the concentration of the solution and the thickness of the medium.
• 💡 The instrumentation of colorimetry includes a light source, lens, split filter, sample holder, photodetector, and amplifier to measure the intensity of transmitted light.
• 🌈 A Tungsten lamp is commonly used as a light source in colorimetry, providing a range of wavelengths from 320 to 7100 nanometers.
• 🔍 The convex lens in colorimetric devices focuses light from the source towards the filter, which selects a narrow wavelength band and blocks unwanted light.
• 🧪 A sample holder or cuvette is essential for holding the colored solution and should be transparent, clean, and free of scratches.
• 🛠️ The photodetector in colorimetric sensors converts the emitted light into an electrical signal, which is then measured and amplified.
• 🏥 Colorimetric sensors have applications in biomedical and healthcare for estimating the concentration of substances in plasma, serum, urine, etc.
• 🍇 They are also used for quantitative estimation of glucose, proteins, and other biochemicals, as well as detecting heavy metals like cadmium in environmental samples.
• 🌱 Pesticides in agricultural or food products and soil can be determined using colorimetric sensors, showcasing their versatility in different fields.

Q & A

What are optical sensors?

Optical sensors are electronic components designed to convert incident light, which interacts with an analyte, into an electrical signal. These signals help detect the physical or chemical properties of the analyte.

How do optical sensors interact with electromagnetic radiation?

Optical sensors interact with electromagnetic radiation such as UV, visible, or IR light by causing absorption, emission, reflection, or scattering of light. The intensity of the transmitted light after interaction provides information about the analyte's concentration.

What is a colorimetric sensor?

A colorimetric sensor is the simplest type of optical sensor that operates in the visible region (400 to 800 nanometers) and is used to determine the concentration of colored chemical species.

What principle governs the quantity of light absorbed by a colored sample?

The quantity of light absorbed by a colored sample is governed by Lambert's law, which states that the absorbance of light is directly proportional to the concentration of the solution and the thickness of the medium.

What is the role of a light source in colorimetry?

In colorimetry, the light source emits light of different wavelengths. A Tungsten lamp is commonly used, providing light in the range of 320 to 7100 nanometers.

What is the function of a convex lens in a colorimetric setup?

The convex lens in a colorimetric setup focuses the light from the source towards the filter, ensuring that only a particular wavelength of light passes through while blocking unwanted light.

What is the purpose of a monochromator or filter in colorimetry?

A monochromator or filter in colorimetry allows only a specific wavelength of light to pass and blocks all other wavelengths, ensuring that the light interacting with the sample is monochromatic.

What is the role of a sample holder or cuvette in colorimetry?

A sample holder or cuvette is used to hold the colored solution in colorimetry. It should be transparent, clean, and without scratches to ensure accurate light transmission.

How is the light emitted after passing through the sample converted into an electrical signal?

The emitted light after passing through the sample reaches a photodetector, which converts the light into an electrical signal. This signal is then measured using a galvanometer and amplified in an amplifier.

What are some biomedical and healthcare applications of colorimetric sensors?

Colorimetric sensors are used for estimating plasma, serum, urine, and other biochemicals like glucose and proteins in biomedical and healthcare applications.

How can colorimetric sensors be used in environmental and agricultural contexts?

Colorimetric sensors can detect heavy metals such as cadmium in environmental samples and pesticides in agricultural products, food products, or soil.

Outlines

00:00

🌈 Understanding Optical Sensors and Colorimetry

This paragraph provides an in-depth explanation of optical sensors, which are electronic components designed to convert light into electrical signals. It highlights the interaction of electromagnetic radiation with analytes, resulting in various light behaviors such as absorption, emission, reflection, or scattering. The focus then shifts to colorimetric sensors, a type of optical sensor that operates in the visible light spectrum (400 to 800 nanometers) and is used to determine the concentration of colored chemical species. The principle of colorimetry is explained through Lambert's law, which states that the absorbance of light is directly proportional to the concentration of the solution and the thickness of the medium. The instrumentation of colorimetry is described, including the light source, lens, filter, sample holder, photodetector, and the process of light absorption and detection. Applications of colorimetric sensors in biomedical, healthcare, environmental, and agricultural fields are mentioned, emphasizing their utility in detecting substances like glucose, proteins, heavy metals, and pesticides.

05:01

🌟 Applications of Colorimetric Sensors

This paragraph briefly summarizes the applications of colorimetric sensors, building on the detailed explanation provided in the previous paragraph. It reiterates the use of these sensors in various fields such as biomedical and healthcare for analyzing substances like plasma, serum, and urine. Additionally, the paragraph mentions the quantitative estimation of biochemicals like glucose and proteins, as well as the detection of heavy metals in environmental samples and pesticides in agricultural products. The concise nature of this paragraph serves to reinforce the wide-ranging utility of colorimetric sensors in different industries.

Keywords

💡Optical sensors

Optical sensors are electronic components that convert light into electrical signals. They are designed to interact with analytes, substances being analyzed, and convert the light's interaction into a measurable electrical signal, which can indicate the physical or chemical properties of the analyte. In the context of the video, optical sensors are crucial for detecting the concentration of substances through the measurement of light absorption, reflection, or scattering.

💡Analyte

An analyte refers to the chemical substance being analyzed or tested. In the video, the interaction of analytes with electromagnetic radiation such as UV, visible, or IR light is essential for optical sensors to function, as it leads to phenomena like absorption or emission, which the sensors can then detect and measure.

💡Colorimetric sensors

Colorimetric sensors are a type of optical sensor that operates within the visible light spectrum, typically from 400 to 800 nanometers. They are used to determine the concentration of colored chemical species by measuring the amount of light absorbed by the sample. The video emphasizes their simplicity and their application in various fields, including biomedical and environmental analysis.

💡Lambert's law

Lambert's law, also known as Beer's law, states that the absorbance of light by a solution is directly proportional to the concentration of the solution and the path length of the light through the solution. In the video, this law is fundamental to colorimetry, as it governs the relationship between light absorption and the concentration of the analyte.

💡Absorbance

Absorbance is a measure of how much light is absorbed by a substance. It is used in colorimetry to quantify the concentration of a colored analyte by measuring the decrease in light intensity after it passes through the sample. The video script explains that absorbance is directly related to the analyte's concentration and the medium's thickness.

💡Instrumentation of colorimetry

The instrumentation of colorimetry includes a light source, a lens, a split filter, a sample holder, a photodetector, a galvanometer, and an amplifier. The video script describes how these components work together to measure the absorbance of light by a sample, which is then converted into an electrical signal and displayed.

💡Monochromatic light

Monochromatic light refers to light of a single wavelength. In colorimetry, as described in the video, a monochromatic light source is used to ensure that only light of a specific wavelength interacts with the sample, which is crucial for accurate absorbance measurements.

💡Photodetector

A photodetector is a device that converts light into an electrical signal. In the context of the video, the photodetector measures the intensity of the light that has passed through the sample and converts it into an electrical signal that can be further processed and displayed.

💡Biomedical applications

Biomedical applications refer to the use of technology in medical and healthcare fields. The video script mentions that colorimetric sensors are used for estimating the concentration of substances in plasma, serum, urine, and for the quantitative estimation of glucose and proteins, highlighting their importance in diagnostics and health monitoring.

💡Environmental samples

Environmental samples are samples taken from the environment for analysis, such as soil, water, or air. The video script discusses how colorimetric sensors can be used to detect heavy metals like cadmium in environmental samples, emphasizing their role in environmental monitoring and protection.

💡Agricultural products

Agricultural products include crops, livestock, and other commodities produced by farming. The video script explains that colorimetric sensors can be used to determine the presence of pesticides in agricultural products, food products, or soil, which is important for ensuring food safety and environmental health.

Highlights

Optical sensors convert incident light into electrical signals to detect physical or chemical properties of an analyte.

Interaction of electromagnetic radiation with an analyte can result in absorption, emission, reflection, or scattering of light.

The intensity of transmitted light after interaction provides information about the analyte's concentration.

Colorimetric sensors are the simplest type of optical sensor, operating in the visible region (400 to 800 nanometers).

Colorimetric sensors determine the concentration of colored chemical species.

Lambert's law governs the absorption of light by colored samples, stating that absorbance is proportional to concentration and medium thickness.

The emitted radiation after absorption is detected by an optical sensor and converted into an electrical signal.

Colorimetry involves a light source, lens, filter, sample, photodetector, and display.

A Tungsten lamp is commonly used as a light source in colorimetry, providing light in the range of 320 to 7100 nanometers.

A convex lens focuses light from the source to the filter, selecting a narrow wavelength band and blocking unwanted light.

A sample holder or cuvette is used to hold the colored solution, which must be transparent, clean, and scratch-free.

The photodetector converts emitted light into an electrical signal, which is measured using a galvanometer and amplified.

Colorimetric sensors are used in biomedical and healthcare applications for estimating plasma, serum, urine, etc.

They are also used for quantitative estimation of glucose, proteins, and other biochemicals.

Colorimeters can detect heavy metals such as cadmium in environmental samples.

Pesticides in agricultural products, food products, or soil can be determined using colorimetric sensors.

Transcripts

in this session I will explain about

Optical

sensors Optical sensors are the

electronic components which are designed

to convert incident light weights which

are interacted with the analy into

electrical

signal these signals are held to detect

the physical or chemical properties of

the

analy whenever an electromagnetic

radiation is as UV visible or IR

interacted with the analy then that may

result in absorption or emission or

reflection or scattering of

light the intensity of the transmitted

light after

interaction which may be measured by opo

electronic instrument gives the

information about the concentration of

the

analy

out of several Optical sensors

colorimetric sensors are the simplest

type of sensor which is working in the

visible region that is 400 to 800

nanometer hence it is used to determine

the concentration of colored chemical

species now let us see the principle of

colorimetry when a light of suitable

wavelength is interacted with the sample

solution then certain quantity of the

light is absorbed by the colored

sample the quantity of absorption is

governed by be Lambert's law so

according to this law when a

monocromatic light is passed through the

analy solution then the absorbance of

light is directly proportional to the

concentration of the solution and the

thickness of the

medium after absorption whatever

intensity of emitted radiation which is

detected by Optical sensor and converted

into electrical

signal now let us see the

instrumentation of

colorimetry colorimetry contains the

light source which consist of different

wavelength

light these light radiation are passed

through the

lens so that all the radiations focused

towards the split of

filter the filter allows only a

particular wavelength light and blocks

all other

light this monochromatic light then pass

through the

sample the colored sample will absorb

the certain quantity of light based on

its concentration and emits the

remaining light

hence intensity of the light decreases

after passing through the

sample the emitted Light reaches the

photo

detector then it is

Amplified and will be displayed on the

display here usually a Tungsten lamp is

used as light source which gives the

light in the range of 320 to 7 100

nanometer the role of convex lens is to

focus the light from source to

filter the monochromat or the filter

select the narrow Wave band and blocks

The Unwanted

light a sample holder or KU is used to

hold the colored solution hence qu

should be transparent clean and without

scratches

the photo detector converts the emitted

light into electrical

signal which is measured using

galvanometer and Amplified in the

amplifier now let us see some of the

applications of

colorimetry colorimetric sensors are

used for biomedical and Healthcare

applications such as estimation of

plasma serum urine

Etc this type of sensors are also used

for quantitative estimation of glucose

proteins and many other

biochemicals the heavy metals such as

cadmium present in the environmental

samples can also be detected by using

Colorimeter the pesticides present in

the agricultural products or food

products or in the soil can also be

determined by using this color meter

these are some of the applications of

colorimetric

sensors