A chromatography method for separating mixtures into their individual components. In this method, a mixture is separated into its different components based on their different interactions with a stationary phase and mobile phase.
These are ten examples of mixtures that can be separated by chromatography.
What are examples of Mixtures that Can be Separated by Chromatography
1. Amino acids
Amino acids are the building blocks of proteins and are frequently studied in biochemical analysis. Chromatography is a powerful tool that can be used to separate and identify individual amino acids.
2. Plant pigments
Chlorophyll, carotenoids and anthocyanins are plant pigments that give plants their color.
Chromatography can be used to separate and identify these pigments, based on their different interactions with the stationary and mobile phases.
3. Drugs
Chromatography is widely used in the pharmaceutical industry to separate and purify drugs. It can also be used to analyze drug metabolites in biological samples such as blood and urine.
4. Fatty acids
Fatty acids are very important components of lipids and are commonly analyzed in biochemistry.
Chromatography is useful for separating out and identifying different fatty acids based on their chemical properties and interactions with the stationary and mobile phases.
5. Flavors and fragrances
Chromatography is widely used in the food and fragrance industries to separate and identify individual flavor and fragrance compounds. This is important for quality control and product development.
6. Environmental pollutants
Chromatography can be used to separate and identify environmental pollutants such as pesticides, herbicides, and industrial chemicals. This is important for monitoring and regulating these pollutants in the environment.
7. Proteins
Chromatography is used to separate and purify proteins based on their different interactions with the stationary and mobile phases. This is important for protein purification and analysis in biochemistry and biotechnology.
8. DNA fragments
Chromatography is used to separate and purify DNA fragments based on their size and charge. This is important for DNA sequencing, gene cloning, and other molecular biology techniques.
9. Sugars
Chromatography is used to separate and identify individual sugars based on their chemical properties and interactions with the stationary and mobile phases. This is important for analyzing carbohydrates in food and biological samples.
10. Steroids
Chromatography is used to separate and identify individual steroids based on their chemical properties and interactions with the stationary and mobile phases. This is important for analyzing steroid hormones in biological samples and for drug testing.
Bunsen Burner is a laboratory device that is widely used in scientific research, teaching, and experimentation. It is a simple gas burner that produces a hot, blue flame that is perfect for heating, sterilizing, and combustion purposes.
Bunsen Burner Definition
The Bunsen Burner is a laboratory device used to produce a single flame with adjustable heat output.
The device works by mixing gas and air in a controlled manner and then igniting it, resulting in a clean and efficient flame. The Bunsen burner was invented by Robert Bunsen in 1855.
Bunsen Burner History
In 1852, Robert Bunsen was hired by the University of Heidelberg and promised a new laboratory building. The city of Heidelberg was installing coal-gas street lighting, so the university laid gas lines to Bunsen’s new lab.
Bunsen wanted to improve existing laboratory burner lamps by making them more economical, simple, and able to reach high temperatures using coal gas as fuel. He worked with the university’s mechanic, Peter Desaga, to develop a new burner.
The Bunsen/Desaga burner produced a hot, clean, and non-luminous flame by mixing air and gas before combustion. Desaga engineered adjustable air slits at the bottom of the cylindrical burner, with the flame emitting from the top.
When the building opened in early 1855, Desaga had made 50 burners for Bunsen’s students. Just two years later, Bunsen published a description of the burner, and it quickly became popular among his colleagues. Today, Bunsen burners are used in laboratories all over the world.
In the late 19th and early 20th centuries, Bunsen burners were adapted to use natural gas and propane, which became more widely available. Bunsen burners were also improved with features such as safety valves and pilot lights.
Today, Bunsen burners are still an essential tool in many laboratories. However, there are also a number of newer laboratory heating devices available, such as electric hot plates and mantle heaters. Bunsen burners are still used because they are inexpensive, easy to use, and produce a very hot flame.
Developments In Bunsen Burner Technology
Here are some of the most recent developments in Bunsen burner technology:
Electronic Bunsen burners: These burners use electronic controls to regulate the flow of gas and air, which produces a more consistent flame.
Bunsen burners with built-in safety features: These burners have features such as flameout protection and automatic shut-off, which can help to prevent accidents.
Bunsen burners for specialized applications: There are now Bunsen burners that are designed for specific applications, such as microchemistry and combustion analysis.
Bunsen Burner Parts
The Bunsen Burner consists of several parts, each with its own function. These parts include:
Base: The base is a heavy metal stand that provides support and stability to the Bunsen burner. It also helps to protect the laboratory surface from the heat of the flame.
Gas inlet: This is the point where the gas supply, such as natural gas or propane, is connected to the Bunsen burner. The gas inlet is typically located at the bottom of the Bunsen burner.
Needle valve: The needle valve controls the flow of gas into the burner tube. By adjusting the needle valve, you can control the size and intensity of the flame.
Air vent: The air vent controls the flow of air into the burner tube. The amount of air mixed with the gas determines the type of flame produced. A flame with more air will be hotter and more blue, while a flame with less air will be cooler and more yellow.
Burner tube: The burner tube is the main part of the Bunsen burner where the gas and air mixture is ignited to produce a flame. The burner tube is typically made of metal and is designed to withstand high temperatures.
Bunsen Burner Flame
The Bunsen burner flame is a hot, blue flame that is perfect for heating, sterilizing, and combustion purposes. It is a non-luminous flame, which means that it does not produce soot.
The flame consists of three parts: the inner cone, the outer cone, and the non-luminous zone.
The inner cone is the hottest part of the flame, reaching temperatures of up to 1,500 °C (2,700 °F). It is the ideal part of the flame to use for heating and combustion.
The outer cone is cooler than the inner cone, and it is used for sterilization. It is also used to complete the combustion of any remaining gas that was not burned in the inner cone.
The outer cone of the Bunsen burner flame has two main functions:
Sterilization: The outer cone is cooler than the inner cone, so it is ideal for sterilizing laboratory equipment. The heat from the outer cone kills any microorganisms that may be present on the equipment.
Complete combustion: The outer cone also helps to complete the combustion of any remaining gas that was not burned in the inner cone. This helps to prevent the production of soot and other harmful pollutants.
The inner cone of the Bunsen burner flame is hotter than the outer cone. This is because the inner cone is where the gas and air mixture is first ignited. The outer cone is cooler because it further away from the heat source and is exposed to more air.
The outer part of the flame is hotter because it is exposed to more oxygen. Oxygen is necessary for combustion, and the outer cone of the flame has more oxygen than the inner cone.
The needle valve controls the flow of gas into the Bunsen burner. By adjusting the needle valve, you can control the size and intensity of the flame.
The flame of a Bunsen burner turns yellow when there is too little oxygen in the mixture. This can happen if the needle valve is closed too far or if there is a blockage in the air vent.
6 Types of Bunsen Burners
There are different types of Bunsen Burners available, including:
1. Portable Bunsen burner
It is most common type of Bunsen burner used in a variety of laboratory applications. Small and lightweight, making it easy to move around. Typically powered by natural gas or propane.
2. Strike back Bunsen burner
It is designed to be used in places where there is a risk of gas leaks. Has a special feature that prevents the flame from striking back into the burner tube. Typically used in industrial settings.
3. Electric Bunsen burner
It is powered by electricity instead of gas. Safer and more environmentally friendly than gas-powered Bunsen burners. More expensive and less versatile than gas-powered Bunsen burners.
4. Meker burner
It produces a hotter and more uniform flame than a standard Bunsen burner. Often used in laboratories for heating samples and conducting combustion reactions.
5. Fisher burner
Fisher burners use forced air to create a hotter flame. They are often used in industrial settings for heating and melting metals.
6. Tirrill burner
It has a disc valve at the base of the burner tube that controls the flow of gas. Often used in schools and universities for teaching students about laboratory safety and procedures.
Functions
Here are some of the specific functions of the Bunsen burner:
Heating liquids: The Bunsen burner can be used to heat liquids for a variety of purposes, such as dissolving chemicals, conducting chemical reactions, and preparing samples for analysis.
Sterilizing laboratory equipment: The Bunsen burner can be used to sterilize laboratory equipment by exposing it to a high temperature flame. This helps to prevent the spread of contamination in the laboratory.
Conducting combustion reactions: The Bunsen burner can be used to conduct combustion reactions, which are chemical reactions that involve the burning of a substance in oxygen. Combustion reactions are used in a variety of laboratory experiments, such as identifying substances and measuring the energy content of fuels.
To use a Bunsen Burner, first connect the gas supply to the gas inlet, and then adjust the air vent and needle valve to get the desired flame. Finally, ignite the flame using a striker or a match.
How to light a Bunsen Burner?
To light a Bunsen Burner, turn on the gas supply and adjust the air vent and needle valve to get the desired flame. Finally, use a striker or a match to ignite the flame.
A graduated cylinder is a piece of laboratory glassware used to measure the volume of liquids. It consists of a cylindrical tube with a narrow, vertical scale marked on the outside, allowing the user to read the volume of the liquid with a high degree of accuracy.
In this article, we’ll explore the definition, types, sizes, and functions of graduated cylinders, as well as some frequently asked questions about their use.
Like other chemistry lab apparatus Graduated cylinders are often made of glass or plastic, with glass being the preferred material for most scientific applications due to its durability and resistance to chemical attack.
Measurement
To read the volume of a liquid in a graduated cylinder accurately, the reading must be taken at eye level and at the bottom of the meniscus. The meniscus is the curved surface of the liquid that is caused by the attraction of the liquid molecules to the walls of the cylinder.
The most accurate reading that can be taken from the graduated cylinder in the picture is 1 mL. The error in the reading is one tenth of the least figure, which is 0.1 mL.
For example, if the reading is 36.5 mL, the precise value is 36.5 ± 0.1 mL. This means that the actual volume of the liquid is between 36.4 mL and 36.6 mL.
Similarly, if the reading is 40.0 mL, the precise value is 40.0 ± 0.1 mL. This means that the actual volume of the liquid is between 39.9 mL and 40.1 mL.
In both cases, there are 3 significant figures in the reading. The first two digits are certain, and the third digit is an estimate.
Accuracy of a Graduated Cylinder
The accuracy of a graduated cylinder is determined by the size of the graduations and the class of the cylinder.
The size of the graduations is the smallest volume increment that can be accurately measured. For example, a 100 mL graduated cylinder with 1 mL graduations can accurately measure volumes from 0 mL to 100 mL in increments of 1 mL.
The class of the cylinder indicates its accuracy. Class A graduated cylinders are more accurate than class B graduated cylinders. Class A cylinders have a tolerance of ±0.02 mL, while class B cylinders have a tolerance of ±0.08 mL.
Types of Graduated Cylinders
There are two main types of graduated cylinders: tall-form and short-form. Tall-form cylinders have a height-to-diameter ratio of about 2:1, meaning they are twice as tall as they are wide.
Short-form cylinders, on the other hand, have a height-to-diameter ratio of about 1:1, making them shorter and wider than tall-form cylinders. Short-form cylinders are often used for more precise measurements of smaller volumes, while tall-form cylinders are better suited for larger volumes.
Sizes of Graduated Cylinders
Graduated cylinders come in a wide range of sizes, typically ranging from 10 milliliters (mL) to 2,000 mL. The size of the cylinder will determine the maximum volume of liquid that the cylinder can hold.
The most common sizes are 10 mL, 25 mL, 50 mL, 100 mL, 250 mL, and 500 mL. Smaller cylinders are typically used for more precise measurements, while larger cylinders are used for measuring larger volumes of liquids.
Glass graduated cylinders are available in three sizes: 500 mL, 1000 mL, and 2000 mL. These cylinders are made from borosilicate glass, which is a type of glass that is resistant to heat and chemicals.
The scales on glass graduated cylinders are typically marked in 5 mL, 10 mL, and 20 mL increments.
Plastic graduated cylinders are also available in a variety of sizes. These cylinders are typically made from polypropylene, which is a type of plastic that is resistant to chemicals.
The scales on plastic graduated cylinders are typically marked in 1 mL, 2 mL, and 5 mL increments.
Uses of Graduated Cylinders
Measuring cylinders performs following functions in lab:
Measuring cylinders are used to measure the volume of liquids, solids, and mixtures.
They can also be used to mix liquids and to pour liquids from one container to another.
Graduated cylinders are made of glass or plastic and come in a variety of sizes.
When using a graduated cylinder, it is important to read the scale at the bottom of the meniscus.
FAQs
How do you read a graduated cylinder?
To read a graduated cylinder, simply read the scale at the level of the liquid. The scale is marked in milliliters or other units of volume, and the volume is read to the nearest division of the scale.
How do you use a graduated cylinder?
To use a graduated cylinder, fill it with the liquid to be measured, making sure that the bottom of the meniscus (the curved surface of the liquid) is at the desired level on the scale. Then, read the volume of the liquid from the scale.
How do you find the volume of water in a graduated cylinder?
To find the volume of water in a graduated cylinder, simply read the volume from the scale at the level of the water. Make sure to take into account the meniscus when reading the volume.
What does a graduated cylinder measure?
Graduated Cylinders measures volume of different solvents, mixtures, and solutions.
Beakers are an essential laboratory tool that are used to hold and measure liquids. They are cylindrical in shape with a flat bottom, and are available in various sizes and materials. In this article, we’ll explore the different types of beakers, their functions, chemistry, uses, and frequently asked questions.
Types of Beakers
Beakers come in different sizes, with the most common being 50 ml, 100 ml, 250 ml, 500 ml, and 1000 ml. They can be made of glass or plastic, and some are graduated with markings to measure liquids accurately. Glass beakers are preferred in chemistry labs due to their transparency and chemical resistance.
Beaker Function
Beakers are primarily used to hold and mix liquids. They are not designed for precise measurements, but can be used to estimate volumes of liquids. Beakers can also be used for heating or cooling liquids, as they are made of materials that can withstand changes in temperature.
Beaker Chemistry
Beakers are typically made of borosilicate glass, a type of glass that is resistant to thermal shock and chemical corrosion. This makes them ideal for use in chemistry labs, where they can withstand exposure to various chemicals and extreme temperatures.
Beaker Diagram
A beaker is a cylindrical vessel with a flat bottom and a spout. It is open at the top and can hold liquids of varying volumes. Some beakers have graduations on the side to measure the volume of the liquid in the beaker.
Beaker Uses
Mixing solutions: Beakers are commonly used to mix solutions in a laboratory setting. They can be used to dissolve solids or mix liquids together.
Measuring liquids: Although beakers are not designed for precise measurements, they can be used to estimate volumes of liquids.
Heating or cooling liquids: Beakers can be used to heat or cool liquids, as they are made of materials that can withstand changes in temperature.
Titration: Beakers are used for titrations, a type of chemical analysis that involves adding a reagent to a solution until a reaction is complete.
Storage: Beakers can be used to store small amounts of liquids for a short period of time.
Reacting chemicals: Beakers can be used to react chemicals together to produce a new compound or to observe the reaction between two substances.
Observing chemical reactions: Beakers can be used to observe chemical reactions, as they are transparent and can show the changes in the color or texture of the liquid.
Transferring liquids: Beakers can be used to transfer small amounts of liquid from one container to another.
Dispensing liquids: Beakers with a spout can be used to dispense liquids in a controlled manner.
What is a beaker used for?
A beaker is a laboratory tool that is used to hold and measure liquids.
Why is a beaker used in chemistry lab?
Beakers are used in chemistry labs because they are made of materials that can withstand exposure to various chemicals and extreme temperatures. They are also transparent, which makes it easy to observe the liquid inside.
Who invented the beaker?
The beaker is a traditional laboratory tool that has been in use for centuries. It is not clear who invented the beaker, but it has been used in various forms since the ancient times. The modern glass beaker was first manufactured by the German company Schott AG in the 20th century.
Pipettes are essential tools in a laboratory setting that are used to measure and transfer small volumes of liquids. In this article, we’ll explore the different types of pipettes, their chemistry, accuracy, important parts, and various uses.
Pipette Definition
A pipette is a laboratory tool that is used to measure and transfer small volumes of liquids accurately. It is a cylindrical glass or plastic tube that has a narrow end for transferring liquids, and a bulb or other mechanism for drawing up the liquid.
Types of Pipettes
Gilson Pipette: These are used for high precision measurements and are available in both single and multichannel formats.
Micropipette: These are used to measure very small volumes of liquid, typically in the range of microliters or even nanoliters.
Eppendorf Pipette: These are similar to micropipettes and are commonly used in molecular biology and biochemistry labs.
Pasteur Pipette: These are used to transfer small volumes of liquid from one container to another.
Volumetric Pipette: These are used to accurately measure a specific volume of liquid.
Serological Pipette: These are used in the medical industry to measure and transfer small volumes of liquid for medical testing.
Graduated Pipette: These are used to measure and transfer different volumes of liquid, and have markings on the side to indicate the volume of liquid being measured.
Positive Displacement Pipette: These are used to measure and transfer highly viscous or volatile liquids.
Pipette Chemistry
Pipettes are typically made of glass or plastic, and are designed to be chemically resistant to the liquids they are used to transfer. They can be made from borosilicate glass or plastic materials that can withstand changes in temperature and exposure to different chemicals.
Pipette Accuracy
The accuracy of a pipette depends on the type and model of the pipette being used. Some pipettes are designed for high precision measurements, while others are less accurate. The accuracy can also be affected by factors such as the temperature and viscosity of the liquid being transferred.
Important Parts of Pipette:
Pipette Tips: The tips of a pipette are disposable and come in various sizes and materials. They are designed to fit onto the narrow end of the pipette and allow for accurate transfer of liquids.
Pipette Bulb: The bulb or other mechanism is used to draw up the liquid into the pipette.
Pipette Diagram: A pipette has a narrow end for transferring liquids and a bulb or other mechanism for drawing up the liquid.
Pipette Dropper: The dropper is the narrow end of the pipette that is used to transfer the liquid.
Pipette Filler
A pipette filler is a tool that is used to draw up liquid into a pipette without the need for a pipette bulb. It is a handheld device that is attached to the top of the pipette, and can be used to control the amount of liquid being transferred.
Pipette Pump
A pipette pump is a tool that is used to draw up liquid into a pipette without the need for a pipette bulb. It is a handheld device that is attached to the top of the pipette, and can be used to control the amount of liquid being transferred.
Pipette Sucker
A pipette sucker is a tool that is used to draw up liquid into a pipette without the need for a pipette bulb. It is a handheld device that is attached to the top of the pipette, and can be used to control the amount of liquid being transferred.
Uses of pipette
Chemical Analysis: Pipettes are commonly used for chemical analysis, such as titrations and sample preparation for spectroscopic analysis.
Preparing Solutions: In chemistry, solutions with specific concentrations are required, and pipettes are used to prepare these solutions. Volumetric pipettes are commonly used for preparing solutions of a specific volume and concentration.
Sample Handling: Pipettes are used to transfer small volumes of liquids, such as samples or reagents, for further processing or analysis.
Dilution: Pipettes are used for diluting a solution, which is the process of reducing the concentration of a solution by adding more solvent.
Addition of Reagents: In many chemical reactions, reagents need to be added in specific amounts and in a controlled manner. Pipettes allow for the precise addition of reagents to a reaction mixture.
Quality Control: In manufacturing processes, pipettes are used for quality control purposes, such as ensuring that products are made to specific standards.
pH Measurements: Pipettes are used in pH measurements, where the addition of an acidic or basic solution is required to adjust the pH of the sample.
Cell Culture: Pipettes are used in cell culture techniques for adding or removing small volumes of culture medium, which contains essential nutrients for the growth of cells.
FAQs
What are the 3 types of pipettes?
There are several types of pipettes available, but the most common are volumetric pipettes, graduated pipettes, and micropipettes.
What is pipette and burette?
Both pipettes and burettes are laboratory tools used for precise liquid measurement. The main difference is that pipettes are used for smaller volumes of liquid, whereas burettes are used for larger volumes.
Is it pipette or pipet?
Both spellings are correct, but “pipette” is more commonly used in modern English.
What is pipetting in a lab?
Pipetting refers to the process of using a pipette to measure and transfer a specific volume of liquid from one container to another in a laboratory setting.
What is a pipette used for?
Pipettes are used for precise measurement and transfer of small volumes of liquid in laboratory settings.
What is the pipette tool called?
The main tool used with a pipette is the pipette tip, which is disposable and comes in various sizes to match the pipette being used.
What is the working principle of pipette?
The working principle of a pipette involves drawing up a specific volume of liquid into the pipette and then transferring it to another container, either by using the pipette’s release mechanism or by blowing it out.
What is the range of pipette?
The range of a pipette refers to the volume of liquid that can be accurately measured by the pipette. The range can vary depending on the type of pipette and can range from microliters to milliliters.
A thermometer is a device used for measuring temperature. It typically consists of a temperature sensor, which could be a liquid or gas, and a scale for displaying the temperature reading.
Principle of Thermometer
Thermometers work based on the principle that certain materials expand or contract with temperature changes. As the temperature increases, the material in the thermometer expands, and as the temperature decreases, it contracts. This expansion and contraction is then translated into a temperature reading on the thermometer’s scale.
Working of Thermometer
The working of a thermometer depends on the type of thermometer. In general, when the temperature changes, the material in the thermometer expands or contracts, causing the reading to change. The most common type of thermometer is a liquid-in-glass thermometer, where a liquid, such as mercury or alcohol, is placed in a glass bulb and as the temperature changes, the liquid expands or contracts, causing it to move up or down a calibrated scale.
Types of Thermometer
There are various types of thermometers available, some of which include:
Digital Thermometer: A thermometer that uses an electronic sensor to measure temperature and displays the reading on a digital screen.
Infrared Thermometer: A thermometer that measures temperature without making contact with the object being measured, using infrared radiation.
Meat Thermometer: A thermometer used for measuring the internal temperature of cooked meat to ensure that it is safe to eat.
Mercury Thermometer: A traditional type of thermometer that uses mercury to measure temperature. Due to the health and environmental hazards associated with mercury, these are being phased out.
Galileo Thermometer: A decorative thermometer that consists of a glass tube containing a liquid and several glass spheres of different densities. As the temperature changes, the spheres rise or fall, indicating the temperature.
Forehead Thermometer: A non-contact thermometer that measures the temperature of the forehead using infrared technology.
Thermometer Uses in Chemistry Lab
In the chemistry lab, thermometers are used to measure the temperature of a sample or a reaction. This is important because many chemical reactions are temperature-sensitive and require precise temperature control to achieve the desired outcome. Thermometers are also used to calibrate other temperature measuring instruments, such as ovens and incubators.
A hot plate is a laboratory device used to heat and maintain the temperature of a sample.
It typically consists of a flat metal plate that is heated by an electrical coil or other heat source.
Hot plate is used as advance Lab research tool in research labs Like natural product chemistry and synthetic chemistry.
Principle of Hot Plate
Hot plates work based on the principle of heating through conduction. When a sample is placed on the hot plate, the heat is transferred from the plate to the sample through direct contact.
Working of Hot Plate
Hot plates are typically operated using a variable temperature control, which allows the user to set and adjust the desired temperature of the sample. The temperature control is connected to a heating element that is embedded in the plate.
When the user sets the desired temperature, the heating element is activated, and the plate begins to heat up. The sample is then placed on the hot plate, and the heat is transferred from the plate to the sample through conduction.
Types of Hot Plate in Chemistry Lab
There are several types of hot plates available for use in the chemistry lab, some of which include:
Magnetic Hot Plate: A hot plate that includes a magnetic stirrer for stirring the sample while it is being heated.
Gas Hot Plate: A hot plate that is powered by natural gas or propane.
Electric Hot Plate: A hot plate that is powered by electricity.
Temperature-Controlled Hot Plate: A hot plate that includes a feedback control system to maintain the temperature of the sample at a constant level.
Uses of Hot Plate in Chemistry Lab
Hot plates are commonly used in the chemistry lab for a variety of purposes, including:
Heating of Solvents: Hot plates are often used to heat solvents, which are used in many chemical reactions.
Evaporation of Solvents: Hot plates can be used to evaporate solvents, leaving behind a solid sample.
Melting of Substances: Hot plates can be used to melt substances, making them easier to work with.
Maintaining Temperature: Hot plates can be used to maintain a constant temperature in a sample, which is often necessary in certain chemical reactions.
FAQs
What is a hot plate used for in a lab?
A hot plate is a laboratory device that is used to heat and maintain the temperature of a sample. It is commonly used in the chemistry lab for a variety of purposes, including heating of solvents, evaporation of solvents, melting of substances, and maintaining a constant temperature in a sample.
What is the purpose of hot plate?
The purpose of a hot plate is to heat and maintain the temperature of a sample in the laboratory. It is an important tool for many chemical reactions that require precise temperature control to achieve the desired outcome.
What is the working principle of hot plate?
Hot plates work based on the principle of heating through conduction. When a sample is placed on the hot plate, the heat is transferred from the plate to the sample through direct contact. The hot plate typically consists of a flat metal plate that is heated by an electrical coil or other heat source. The user sets the desired temperature using a variable temperature control, and the heating element is activated to heat the plate. The sample is then placed on the plate, and the heat is transferred through conduction.
Column chromatography is a widely used technique of chromatography in chemistry to separate and purify a mixture of chemical compounds. Mostly it is used in natural product isolation.
I also used this technique during my research on Boerhavia Procumbens. The goal of this technique is to isolate each component in a mixture based on its physical and chemical properties. In this article, we will take a closer look at what column chromatography is, its principle, procedure, and applications.
What is Column Chromatography?
Column chromatography is a separation technique in which a column is used. The column is filled with a solid stationary phase which is silica. it is tightly packed for better separation. A liquid mobile phase to separate a mixture of chemical compounds is passed through the column. The mobile phase dissolves compounds and flows out of the column.
Column Chromatography Principle
The principle of column chromatography is based on the fact that different components in a mixture have different affinities for the stationary and mobile phases. When the mixture is passed through the column, the components will separate based on their different interactions with the stationary and mobile phases. This allows each component to be isolated and collected separately.
Common mobile and stationary phase used in column chromatography
Mobile Phase
Stationary Phase
Hexane
Silica gel
Ethanol
Sephadex LH-20
Acetonitrile
C18
Methanol
Florisil
Water
Reverse-phase silica
Toluene
Alumina
Chloroform
Diol
Acetone
Ion exchange resins
Isopropanol
Cellulose
Petroleum ether
Polymeric resins
Table showing different mobile and stationary phases used in column chromatography
Column Chromatography Diagram
A column chromatography setup typically consists of a column, a pump, a detector, and a collection system, and holding clamps. A detector is used in advance columns. At basic level it is done manually by performing thing layer chromatography and checking it under uv lamp.
The column is filled with the stationary phase and the mixture is introduced at the top of the column. The mobile phase is then pumped through the column, carrying the mixture along with it. As the mixture passes through the column, the components will separate based on their different interactions with the stationary and mobile phases. The separated components are then collected at the bottom of the column.
Column Chromatography Procedure
The procedure for column chromatography can vary depending on the type of column and the specific requirements of the separation. However, the basic steps of a column chromatography procedure are as follows:
Prepare the stationary phase and fill the column with it.
Load the mixture to be separated at the top of the column.
Start the flow of the mobile phase through the column.
Monitor the progress of the separation with a detector.
Collect the separated components at the bottom of the column.
Perform elution to wash the components from the column.
Column Chromatography Experiment
Column chromatography experiments are a key part of many chemistry research projects and are used to separate and purify different components in a mixture. The following is a step-by-step guide to performing a column chromatography experiment:
1: Choose the appropriate column chromatography technique
There are several different techniques of column chromatography to choose from, including ion exchange chromatography, gel filtration chromatography, reverse phase chromatography, affinity chromatography, and hydrophobic interaction chromatography. The choice of technique will depend on the properties of the mixture and the desired outcome of the separation.
2: Prepare the stationary phase
The stationary phase is the material in the column that will retain the components of the mixture. It is important to choose the appropriate stationary phase for the separation and to prepare it according to the manufacturer’s instructions.
3: Load the mixture
The mixture to be separated should be carefully loaded into the column. It is important to take care not to damage the stationary phase or to introduce any contaminants into the column.
4: Start the flow of the mobile phase
The mobile phase is the liquid that will flow through the column and carry the mixture along with it. It is important to choose the appropriate mobile phase for the separation and to set the flow rate correctly.
5: Monitor the progress of the separation
The progress of the separation can be monitored using a detector, such as a UV-Vis spectrophotometer. The detector measures the amount of each component in the mixture as it passes through the column.
6: Collect the separated components
The separated components will be collected at the bottom of the column. It is important to collect the components in a way that preserves their purity and to store them correctly for further analysis.
7: Perform elution
Elution is the process of washing the separated components from the column. This is done by changing the conditions of the mobile phase, such as the solvent or the flow rate, to release the retained components from the stationary phase. The eluted components are then collected for further analysis or use.
In conclusion, a column chromatography experiment is a carefully controlled process that requires careful attention to detail in order to obtain accurate and reproducible results. By following the steps outlined above, you can perform a successful column chromatography experiment and obtain high-quality separated components for your research.
Types of Column Chromatography
There are several types of column chromatography, each with its own unique characteristics and applications. Some of the most commonly used types of column chromatography include:
Ion Exchange Column Chromatography
Gel Filtration Chromatography
Reverse Phase Chromatography
Affinity Chromatography
Hydrophobic Interaction Chromatography
Column Chromatography Applications
Column chromatography is a powerful tool for separating and purifying different components in a mixture. The following are some of the most common applications of column chromatography:
Biotechnology: Column chromatography is used extensively in the biotechnology industry to purify proteins and other biological molecules for use in research and as therapeutic drugs.
Pharmaceuticals: Column chromatography is used in the pharmaceutical industry to purify active ingredients and impurities from drug products. This is important for ensuring the quality and safety of drugs.
Environmental analysis: Column chromatography is used in environmental analysis to separate and identify contaminants in water, air, and soil samples.
Food and beverage analysis: Column chromatography is used in the food and beverage industry to analyze food ingredients, such as vitamins and minerals, and to monitor the quality of food and beverage products.
Analytical chemistry: Column chromatography is a common technique in analytical chemistry for separating and purifying different components in a sample for further analysis. This can be used in fields such as drug discovery, forensic science, and metabolic profiling.
Process chromatography: Column chromatography is also used in process chromatography to purify large quantities of a product, such as a food ingredient or a pharmaceutical, for commercial use.
Gas Chromatography (GC) is a powerful analytical technique used to separate and identify individual components in a mixture of gases or volatile liquids.
Gas chromatography is a method of separation in which the components of a mixture are distributed between a stationary phase and a mobile phase. The stationary phase is a solid or a liquid, while the mobile phase is a gas. The components of the mixture are separated based on their chemical and physical properties, such as boiling point, vapor pressure, and polarity.
Principal of gas chromatography
The basic principle of gas chromatography is that different compounds in a mixture will have different interactions with the stationary phase, and will therefore travel at different rates through the column.
The compound that interacts least with the stationary phase will travel through the column the fastest, while the compound that interacts most with the stationary phase will travel through the column the slowest. This results in the separation of the compounds in the mixture.
Example
For example, let’s say we have a mixture of three compounds: A, B, and C. Compound A has a higher boiling point than compounds B and C, so it will interact more with the stationary phase and travel through the column more slowly. Compound B has a lower boiling point than compound A but higher than compound C, so it will travel through the column at a faster rate than compound A, but slower than compound C. Compound C, having the lowest boiling point, will travel through the column the fastest.
Mobile phase and stationary phase in gas chromatography
Mobile Phase
Stationary Phase
Helium
Polydimethylsiloxane (PDMS)
Nitrogen
Polyethylene glycol (PEG)
Hydrogen
Porous polymer beads (e.g. Tenax)
Argon
Carbon-based materials (e.g. Graphitized Carbon)
Carbon dioxide
Cyclodextrins
Methane
Metal-organic frameworks (MOFs)
Oxygen
Silica gel
Air
Alumina
Propane
Polystyrene divinylbenzene (PS-DVB)
Butane
Cyanopropylphenyl polysiloxane
Table showing different mobile and stationary phases used in gas chromatography
Instrumentation of gas chromatography
In gas chromatography, the key components of the instrumentation include the injector, the separation column, the detector, and the data system.
Injector: The injector is used to introduce the sample into the gas chromatograph. The most common types of injectors are the split injector and the on-column injector. The split injector is the most widely used and allows for the introduction of a large sample volume into the column. The on-column injector is used for trace analysis and allows for the introduction of a smaller sample volume into the column.
Separation Column: The separation column is where the actual separation of the compounds in the sample occurs. The column is typically made of a long, thin tube filled with a stationary phase. The stationary phase can be a liquid or a solid, and is chosen based on the properties of the compounds being analyzed. The most common types of stationary phases are polar and non-polar, and they are used to separate the compounds in the sample based on their polarity.
Detector: The detector is used to detect the separated compounds as they exit the column. The most common types of detectors used in gas chromatography are flame ionization detectors (FID), thermal conductivity detectors (TCD) and mass spectrometry (MS). The FID is sensitive to all types of compounds and is the most widely used detector. The TCD is sensitive to non-volatile compounds and is used for trace analysis. Mass spectrometry is a powerful detector that allows for the identification and quantification of the compounds in the sample.
Data System: The data system is used to collect, process, and display the data generated by the gas chromatograph. The data system typically includes a computer, a data acquisition system, and software for data processing and analysis.
In summary, the instrumentation of gas chromatography includes the injector, which is used to introduce the sample into the chromatograph, the separation column, where the actual separation of the compounds occurs, the detector, which is used to detect the separated compounds and the data system, which is used to collect, process and display the data generated by the gas chromatograph.
Application of gas chromatography
Gas chromatography (GC) is a powerful analytical technique that is widely used in a variety of fields, including chemistry, environmental science, and forensic science. Some of the most common applications of GC include:
Analysis of volatile organic compounds (VOCs) in air and water: GC is commonly used to measure the concentrations of VOCs in air and water, such as benzene, toluene, and xylene. This information can be used to assess air and water quality and identify sources of pollution.
Analysis of food and flavorings: GC is used to identify and quantify the various compounds present in food and flavorings. This information is used to ensure the quality of food products, as well as to develop new flavors and fragrances.
Analysis of pesticides and other toxins in food and water: GC is used to detect and quantify the presence of pesticides and other toxins in food and water. This information is used to protect public health and ensure the safety of food and water supplies.
Analysis of petrochemical products: GC is used to analyze a wide range of petrochemical products, including gasoline, diesel fuel, and lubricating oils. This information is used to ensure the quality of these products and to identify potential problems such as contamination.
Analysis of drugs and their metabolites in biological fluids: GC is used to detect and quantify the presence of drugs and their metabolites in biological fluids, such as blood and urine. This information is used in forensic science and in the monitoring of drug therapy.
Analysis of environmental pollutants: GC is used to analyze pollutants in the environment such as polychlorinated biphenyls (PCBs) and polyaromatic hydrocarbons (PAHs) in soil and water.
Analysis of essential oils and fragrances: GC is used to identify and quantify the individual compounds present in essential oils and fragrances. This information is used in the production and quality control of these products.
Analysis of gases: GC is used to analyze a wide range of gases such as methane, propane, and carbon dioxide. This information is used in industries such as natural gas production, petrochemical, and fuel storage.
In conclusion, Gas chromatography (GC) is a powerful analytical technique that is widely used in a variety of fields such as chemistry, environmental science, and forensic science. Its ability to separate and identify individual components in a mixture of gases or volatile liquids makes it a valuable tool for analyzing and monitoring a wide range of substances, from volatile organic compounds, food and flavorings, pesticides, petrochemical products, drugs, environmental pollutants, essential oils, fragrances, and gases.
Some of the important meta directing groups are –CN, NO2 -COOH, -CHO, -COR etc.
Because these are electrons withdrawing groups they attract the electrons to a benzene ring. Benzene becomes electron deficient at the ortho and para positions. Therefore incoming electrophile attaches at the meta position.
By drawing the benzene ring’s electrons away toward themselves, these groups reduce the electrons’ availability. The chemical reactivity of benzene is thereby reduced.
Due to the electron-withdrawing effect of such substituents, the ortho and para positions have become more electron deficient than the meta position.
Thus the incoming electrophile will prefer to attack the meta position rather than the ortho and para position.
How electron withdrawing groups are meta directing
It is cleared from above mechanism how meta directing groups directs the incoming electrophile at meta position.
Examples of Meta directing groups
Nitration of nitrobenzene
As you can see in below example of nitration of nitrobenzene that nitro being an electron withdrawing group directs another nitro group on meta position.
Nitration of cyanobenzene
Cyano group is also an electron withdrawing group and directs the nitro group at meta position.
