A centrifuge uses centrifugal force to separate particles in a solution based on differences in size, shape, density, and viscosity. It works by subjecting the dispersed solution to an artificially induced gravitational field through high rotor speeds. Heavier particles sediment to the bottom while lighter particles float to the top. Centrifugation can be used for solid-liquid separation, clarification, classification, degritting, thickening, and analytical or preparative purposes. Analytical centrifugation determines particle properties while preparative centrifugation isolates components. Common rotor types include swinging buckets, fixed angles, and vertical designs suited for different applications. Differential centrifugation separates by successive centrifugation at increasing speeds while density gradient centrifugation improves resolution
Principles and applications of centrifugation pptpoojakamble1609
This document discusses the principles and applications of centrifugation. It defines centrifugation as using centripetal force to separate substances of different densities. There are three main types of centrifuges: low-speed centrifuges which operate at speeds up to 5000rpm; high-speed centrifuges which allow more control over speed and temperature; and ultracentrifuges, the most sophisticated, which operate at very high speeds and require vacuum and temperature control. The main applications of centrifugation are preparative techniques like sedimentation and differential centrifugation, and analytical techniques like density gradient and zonal centrifugation which are used to separate and analyze viruses, organelles, and other particles.
Centrifugation is a process that uses centrifugal force to separate particles in a solution based on their density. It can be used to sediment particles, isolate cellular components like organelles, and separate molecules and complexes. Different types of centrifuges include low-speed, high-speed, and ultracentrifuges, which separate particles through differential centrifugation or density gradient centrifugation. Analytical centrifugation allows observation of fractionation processes and is used to study macromolecules. Centrifugation has various applications including concentration, separation, isolation of organelles, and separation of blood components or cream from milk.
Centrifugation is a process which involves the use of the centrifugal force for the sedimentation of heterogeneous mixtures to separate the two miscible substances ,and also to analyze the hydrodynamic properties of macro molecule with a centrifuge , used in industry and in laboratory setting.
The document discusses centrifuges and centrifugation. It begins by summarizing the early history of centrifuges, including inventions in the 18th and 19th centuries. It then provides definitions and explanations of key terms like centrifuge, centrifugation, and relative centrifugal force. The rest of the document details different types of centrifuges, components of centrifuges, separation techniques, and rotors and tubes used in centrifugation.
The document discusses ultracentrifugation, which uses high centrifugal forces to separate particles in solutions based on size, shape, and density. It describes:
1) How particles experience centrifugal, buoyant, and frictional forces when spun in an ultracentrifuge.
2) Key terms like sedimentation rate, sedimentation coefficient, and angular velocity.
3) Types of ultracentrifugation experiments like sedimentation velocity and equilibrium experiments.
4) Types of preparative ultracentrifugation like differential, density gradient, zonal, and isopycnic centrifugation used to separate cell components.
5) Components of an ultracentrifuge like rotors, buckets,
This document discusses three separation techniques: dialysis, ultrafiltration, and lyophilization. Dialysis uses a semi-permeable membrane to separate molecules based on molecular weight, allowing small molecules to pass through while retaining larger ones. Ultrafiltration concentrates solutions using membranes that retain proteins while allowing water and small molecules to pass through under pressure. Lyophilization, or freeze drying, removes water from a frozen sample by sublimation under vacuum, leaving a dry powder.
Centrifugation uses centrifugal force to separate particles in a solution based on properties like size, shape, density. There are several types of centrifugation including density gradient centrifugation, differential centrifugation, and ultracentrifugation. Density gradient centrifugation separates particles based on buoyant density into zones, while differential centrifugation separates organelles from cells. Ultracentrifugation uses very high speeds and forces particle separation. Centrifugation has many applications in areas like water treatment, biomedical research, and industries like sugar and oil production.
Differential centrifugation is a technique used to separate cellular components like organelles based on sedimentation rate differences caused by varying density, size, shape when spun at increasing centrifugal forces; it involves homogenizing a sample, centrifuging sequentially at low speeds to pellet larger components then higher speeds to further separate smaller ones, allowing fractionation of components from nuclei to ribosomes into pellets and supernatants. Differential centrifugation has applications in separating various mixtures and purifying biomolecules, cells, and subcellular structures.
Principles and applications of centrifugation pptpoojakamble1609
This document discusses the principles and applications of centrifugation. It defines centrifugation as using centripetal force to separate substances of different densities. There are three main types of centrifuges: low-speed centrifuges which operate at speeds up to 5000rpm; high-speed centrifuges which allow more control over speed and temperature; and ultracentrifuges, the most sophisticated, which operate at very high speeds and require vacuum and temperature control. The main applications of centrifugation are preparative techniques like sedimentation and differential centrifugation, and analytical techniques like density gradient and zonal centrifugation which are used to separate and analyze viruses, organelles, and other particles.
Centrifugation is a process that uses centrifugal force to separate particles in a solution based on their density. It can be used to sediment particles, isolate cellular components like organelles, and separate molecules and complexes. Different types of centrifuges include low-speed, high-speed, and ultracentrifuges, which separate particles through differential centrifugation or density gradient centrifugation. Analytical centrifugation allows observation of fractionation processes and is used to study macromolecules. Centrifugation has various applications including concentration, separation, isolation of organelles, and separation of blood components or cream from milk.
Centrifugation is a process which involves the use of the centrifugal force for the sedimentation of heterogeneous mixtures to separate the two miscible substances ,and also to analyze the hydrodynamic properties of macro molecule with a centrifuge , used in industry and in laboratory setting.
The document discusses centrifuges and centrifugation. It begins by summarizing the early history of centrifuges, including inventions in the 18th and 19th centuries. It then provides definitions and explanations of key terms like centrifuge, centrifugation, and relative centrifugal force. The rest of the document details different types of centrifuges, components of centrifuges, separation techniques, and rotors and tubes used in centrifugation.
The document discusses ultracentrifugation, which uses high centrifugal forces to separate particles in solutions based on size, shape, and density. It describes:
1) How particles experience centrifugal, buoyant, and frictional forces when spun in an ultracentrifuge.
2) Key terms like sedimentation rate, sedimentation coefficient, and angular velocity.
3) Types of ultracentrifugation experiments like sedimentation velocity and equilibrium experiments.
4) Types of preparative ultracentrifugation like differential, density gradient, zonal, and isopycnic centrifugation used to separate cell components.
5) Components of an ultracentrifuge like rotors, buckets,
This document discusses three separation techniques: dialysis, ultrafiltration, and lyophilization. Dialysis uses a semi-permeable membrane to separate molecules based on molecular weight, allowing small molecules to pass through while retaining larger ones. Ultrafiltration concentrates solutions using membranes that retain proteins while allowing water and small molecules to pass through under pressure. Lyophilization, or freeze drying, removes water from a frozen sample by sublimation under vacuum, leaving a dry powder.
Centrifugation uses centrifugal force to separate particles in a solution based on properties like size, shape, density. There are several types of centrifugation including density gradient centrifugation, differential centrifugation, and ultracentrifugation. Density gradient centrifugation separates particles based on buoyant density into zones, while differential centrifugation separates organelles from cells. Ultracentrifugation uses very high speeds and forces particle separation. Centrifugation has many applications in areas like water treatment, biomedical research, and industries like sugar and oil production.
Differential centrifugation is a technique used to separate cellular components like organelles based on sedimentation rate differences caused by varying density, size, shape when spun at increasing centrifugal forces; it involves homogenizing a sample, centrifuging sequentially at low speeds to pellet larger components then higher speeds to further separate smaller ones, allowing fractionation of components from nuclei to ribosomes into pellets and supernatants. Differential centrifugation has applications in separating various mixtures and purifying biomolecules, cells, and subcellular structures.
Differential centrifugation is a technique used to separate cell organelles based on their densities. It involves homogenizing tissue to break open cells and mix organelle contents. The homogenate is then centrifuged at increasing speeds, causing organelles like mitochondria and lysosomes to pellet out after centrifuging at 1000g for 15 minutes. Repeating this process with the supernatant at higher speeds allows separation of organelles into fractions based on their sedimentation rates in a centrifugal field. While convenient and economical, differential centrifugation yields impure preparations and poor recovery of organelles.
Centrifugation uses centrifugal force to separate mixtures based on density. There are several types of centrifuges that differ in maximum speed and other features. Desktop centrifuges have the lowest maximum speed below 3000rpm, while ultracentrifuges can reach speeds over 75,000rpm. Centrifuges consist of a drive motor, temperature control, vacuum, and rotors. Sedimentation velocity separates mixtures in a shallow gradient over a short time, while sedimentation equilibrium separates mixtures to their equilibrium positions in a steep gradient over prolonged high-speed centrifugation.
The document describes different types of centrifuges based on their design features and intended applications. Centrifuges vary in maximum speed, capacity, temperature control, and sample volume capabilities. Small benchtop centrifuges are used in clinical labs for blood separation and can hold around 100 tubes. Microcentrifuges are very common in biology labs, can hold small tube volumes, and generate forces up to 15,000g. High speed centrifuges spin at 15,000-20,000 RPM and are used for research applications requiring separation of cellular components. Ultracentrifuges provide the highest speeds and forces but are expensive and require special rotors and cooling due to heat generation.
Ultracentrifugation is a technique that uses very high rotational speeds, up to 80,000 rpm, to separate particles via centrifugal force up to 600,000g. There are two main types: analytical ultracentrifugation monitors particles in real-time to study molecular interactions and properties, while preparative ultracentrifugation isolates and purifies particles like organelles. Common techniques include differential centrifugation to separate organelles and density gradient centrifugation to separate mixtures based on density.
Centrifugation is a process that uses centrifugal force to separate particles or molecules based on their size, shape, or density. It involves spinning a sample in a centrifuge to separate it into its components. There are various types of centrifugation classified based on speed, temperature, or separation method including differential, isopycnic, sucrose gradient, and ultracentrifugation. Centrifugation has many applications in industries like pharmaceuticals, water treatment, and oil extraction as well as in research areas like biochemistry and molecular biology.
Centrifugation is the separation technique commonly used in clinical and research laboratories.
It is based on the behavior of particles in an applied centrifugal field.
More dense components of the mixture move away from the axis of the centrifuge while less dense components of the mixture move towards the axis.
Centrifugation is a mechanical process which involves the use of the centrifugal force to separate particles from a solution according to their size, shape, density, medium viscosity and rotor speed. The larger the size and the larger the density of the particles, the faster they separate from the mixture.
Fplc(fast protein liquid chromatography )Safina Kouser
This document describes Fast Protein Liquid Chromatography (FPLC), which is a chromatography system used to separate proteins and other biomolecules. FPLC uses stationary phases like resins and mobile phases like buffers. It works on the principles of size exclusion, ion exchange, and affinity chromatography. The key components of an FPLC system include pumps, mixers, injection valves, columns, fraction collectors, and detectors. Compared to HPLC, FPLC uses lower pressures, inert materials, and larger columns. Its advantages include reproducibility, simple operation, and suitability for analytical and preparative purposes. Common applications of FPLC include protein analysis, purification of venoms and plasma proteins.
Dialysis is a process that uses a semi-permeable membrane to selectively remove small molecules from a sample based on size. The membrane allows small molecules like salts to diffuse out of a dialysis bag containing the sample solution and into the surrounding buffer solution. This process is used to desalt and purify protein solutions by removing salts and other small contaminants from the sample inside the dialysis bag until equilibrium is reached. The rate of dialysis is affected by factors like temperature, concentration gradient, membrane thickness, and solvent used.
Centrifugation is a technique that uses centrifugal force to separate mixtures based on density. It works by spinning samples at high speeds, which causes heavier components to sediment. There are several types including preparative centrifugation to separate/purify biological samples, analytical centrifugation to determine physical characteristics, differential centrifugation to separate cell components, density gradient centrifugation to separate mixtures based on density differences, and ultracentrifugation using very high speeds. Centrifugation has many applications in research, medicine, and industry.
This document summarizes a presentation on centrifugation given by Bhavika B. Katariya. It defines centrifugation as a process that uses centrifugal force to separate materials of different densities in a suspension. The key principles of centrifugation are explained, including how centrifuges use very strong centrifugal forces compared to gravity alone to separate particles based on density differences. The main types of centrifugation are described as density gradient, differential, and ultra centrifugation. Applications of centrifugation in various fields like biology, chemistry and forensics are also listed.
Hydrophobic interaction chromatography (HIC) is used to purify biomolecules like proteins by exploiting differences in hydrophobicity. It works by separating substances based on their varying strength of interaction with hydrophobic groups attached to an uncharged gel matrix. HIC is useful for downstream purification as it can handle large sample volumes with high salt concentrations and is gentler than other methods, maintaining protein activity. Factors like ligand type, salt concentration, pH, and temperature affect HIC separation. The document evaluates HIC for monitoring plasmid DNA purification, finding it is a simple, rapid and reproducible method to assess purity.
Chromatography was first developed in 1906 by Russian scientist Tswett who separated plant pigments using calcium carbonate columns. The term "chromatography" comes from the Greek words for "color" and "to write". Chromatography separates mixtures based on how their components interact and distribute between a stationary and mobile phase. High performance liquid chromatography (HPLC) uses high pressure to force a mobile phase through a column packed with tiny particles. HPLC provides efficient separation of mixtures and is commonly used in analytical and preparative applications.
Ultracentrifugation uses very high rotational speeds, up to 8000 rpm, to impose centrifugal forces over 600,000g and separate particles based on small differences in properties. There are two main types: analytical ultracentrifugation studies molecular interactions in real-time using optical detection systems, while preparative ultracentrifugation separates larger samples using density gradients to isolate components like organelles. Analytical uses small samples and optical analysis to determine sedimentation coefficients and molecular weights, while preparative separates whole components from mixtures. Both techniques exploit centrifugal force to differentiate particles based on size, shape, density and other factors.
Reverse phase chromatography is a technique where the binding of solutes to a hydrophobic stationary phase occurs via hydrophobic interactions. It uses a stationary phase with hydrophobic ligands chemically bonded to a solid support. Polar mobile phases are used to elute retained solutes from the column. Key parameters that affect separation include the pH, ionic strength, and polarity of the mobile phase, use of gradients or isocratic elution, column length, and addition of ion-pairing agents. Reverse phase chromatography is commonly used to purify biomolecules like proteins, peptides, and nucleic acids.
Precipitation techniques can be used to recover proteins from liquid and remove unwanted byproducts like nucleic acids. Precipitation is usually induced by neutral salts, organic solvents, changing the pH to the isoelectric point, ionic or non-ionic polymers, metal ions, or heat treatment. The most common precipitating agent is ammonium sulfate, which causes proteins to aggregate and precipitate out of solution by restricting water availability and increasing hydrophobic interactions between proteins.
Sedimentation, Basic principle of sedimentation,Nomograph, Centrifugal force, Angular velocity, Type of rotars, Geometry of rotars,Types of centrifuge, calculation of centrifugal field, Safety measures for centrifuges.
Centrifugation is a process that uses centrifugal force to separate mixtures based on density differences. It works by spinning samples at high speeds, causing denser particles to sediment out of solution. There are two main types - preparative centrifugation which separates large amounts of samples, and analytical centrifugation which analyzes small amounts. Centrifugation has many applications including isolating suspensions, isotope separation, and separating cellular components.
Centrifugation is a process that uses centrifugal force to separate mixtures of substances based on density differences. It involves spinning a sample in a centrifuge which causes denser components to migrate outward while less dense components migrate inward. There are various types of centrifugation techniques used for separation in industrial and laboratory settings, including differential centrifugation, density gradient centrifugation, and ultracentrifugation. Centrifugation has many applications such as separating solids from liquids in water treatment, separating blood components, and separating particles in industrial processes.
Centrifugation is a technique used for the separation of particles from a solution according to their size, shape, density, viscosity of the medium and rotor speed. The particles are suspended in a liquid medium and placed in a centrifuge tube. The tube is then placed in a rotor and spun at a define speed.
Differential centrifugation is a technique used to separate cell organelles based on their densities. It involves homogenizing tissue to break open cells and mix organelle contents. The homogenate is then centrifuged at increasing speeds, causing organelles like mitochondria and lysosomes to pellet out after centrifuging at 1000g for 15 minutes. Repeating this process with the supernatant at higher speeds allows separation of organelles into fractions based on their sedimentation rates in a centrifugal field. While convenient and economical, differential centrifugation yields impure preparations and poor recovery of organelles.
Centrifugation uses centrifugal force to separate mixtures based on density. There are several types of centrifuges that differ in maximum speed and other features. Desktop centrifuges have the lowest maximum speed below 3000rpm, while ultracentrifuges can reach speeds over 75,000rpm. Centrifuges consist of a drive motor, temperature control, vacuum, and rotors. Sedimentation velocity separates mixtures in a shallow gradient over a short time, while sedimentation equilibrium separates mixtures to their equilibrium positions in a steep gradient over prolonged high-speed centrifugation.
The document describes different types of centrifuges based on their design features and intended applications. Centrifuges vary in maximum speed, capacity, temperature control, and sample volume capabilities. Small benchtop centrifuges are used in clinical labs for blood separation and can hold around 100 tubes. Microcentrifuges are very common in biology labs, can hold small tube volumes, and generate forces up to 15,000g. High speed centrifuges spin at 15,000-20,000 RPM and are used for research applications requiring separation of cellular components. Ultracentrifuges provide the highest speeds and forces but are expensive and require special rotors and cooling due to heat generation.
Ultracentrifugation is a technique that uses very high rotational speeds, up to 80,000 rpm, to separate particles via centrifugal force up to 600,000g. There are two main types: analytical ultracentrifugation monitors particles in real-time to study molecular interactions and properties, while preparative ultracentrifugation isolates and purifies particles like organelles. Common techniques include differential centrifugation to separate organelles and density gradient centrifugation to separate mixtures based on density.
Centrifugation is a process that uses centrifugal force to separate particles or molecules based on their size, shape, or density. It involves spinning a sample in a centrifuge to separate it into its components. There are various types of centrifugation classified based on speed, temperature, or separation method including differential, isopycnic, sucrose gradient, and ultracentrifugation. Centrifugation has many applications in industries like pharmaceuticals, water treatment, and oil extraction as well as in research areas like biochemistry and molecular biology.
Centrifugation is the separation technique commonly used in clinical and research laboratories.
It is based on the behavior of particles in an applied centrifugal field.
More dense components of the mixture move away from the axis of the centrifuge while less dense components of the mixture move towards the axis.
Centrifugation is a mechanical process which involves the use of the centrifugal force to separate particles from a solution according to their size, shape, density, medium viscosity and rotor speed. The larger the size and the larger the density of the particles, the faster they separate from the mixture.
Fplc(fast protein liquid chromatography )Safina Kouser
This document describes Fast Protein Liquid Chromatography (FPLC), which is a chromatography system used to separate proteins and other biomolecules. FPLC uses stationary phases like resins and mobile phases like buffers. It works on the principles of size exclusion, ion exchange, and affinity chromatography. The key components of an FPLC system include pumps, mixers, injection valves, columns, fraction collectors, and detectors. Compared to HPLC, FPLC uses lower pressures, inert materials, and larger columns. Its advantages include reproducibility, simple operation, and suitability for analytical and preparative purposes. Common applications of FPLC include protein analysis, purification of venoms and plasma proteins.
Dialysis is a process that uses a semi-permeable membrane to selectively remove small molecules from a sample based on size. The membrane allows small molecules like salts to diffuse out of a dialysis bag containing the sample solution and into the surrounding buffer solution. This process is used to desalt and purify protein solutions by removing salts and other small contaminants from the sample inside the dialysis bag until equilibrium is reached. The rate of dialysis is affected by factors like temperature, concentration gradient, membrane thickness, and solvent used.
Centrifugation is a technique that uses centrifugal force to separate mixtures based on density. It works by spinning samples at high speeds, which causes heavier components to sediment. There are several types including preparative centrifugation to separate/purify biological samples, analytical centrifugation to determine physical characteristics, differential centrifugation to separate cell components, density gradient centrifugation to separate mixtures based on density differences, and ultracentrifugation using very high speeds. Centrifugation has many applications in research, medicine, and industry.
This document summarizes a presentation on centrifugation given by Bhavika B. Katariya. It defines centrifugation as a process that uses centrifugal force to separate materials of different densities in a suspension. The key principles of centrifugation are explained, including how centrifuges use very strong centrifugal forces compared to gravity alone to separate particles based on density differences. The main types of centrifugation are described as density gradient, differential, and ultra centrifugation. Applications of centrifugation in various fields like biology, chemistry and forensics are also listed.
Hydrophobic interaction chromatography (HIC) is used to purify biomolecules like proteins by exploiting differences in hydrophobicity. It works by separating substances based on their varying strength of interaction with hydrophobic groups attached to an uncharged gel matrix. HIC is useful for downstream purification as it can handle large sample volumes with high salt concentrations and is gentler than other methods, maintaining protein activity. Factors like ligand type, salt concentration, pH, and temperature affect HIC separation. The document evaluates HIC for monitoring plasmid DNA purification, finding it is a simple, rapid and reproducible method to assess purity.
Chromatography was first developed in 1906 by Russian scientist Tswett who separated plant pigments using calcium carbonate columns. The term "chromatography" comes from the Greek words for "color" and "to write". Chromatography separates mixtures based on how their components interact and distribute between a stationary and mobile phase. High performance liquid chromatography (HPLC) uses high pressure to force a mobile phase through a column packed with tiny particles. HPLC provides efficient separation of mixtures and is commonly used in analytical and preparative applications.
Ultracentrifugation uses very high rotational speeds, up to 8000 rpm, to impose centrifugal forces over 600,000g and separate particles based on small differences in properties. There are two main types: analytical ultracentrifugation studies molecular interactions in real-time using optical detection systems, while preparative ultracentrifugation separates larger samples using density gradients to isolate components like organelles. Analytical uses small samples and optical analysis to determine sedimentation coefficients and molecular weights, while preparative separates whole components from mixtures. Both techniques exploit centrifugal force to differentiate particles based on size, shape, density and other factors.
Reverse phase chromatography is a technique where the binding of solutes to a hydrophobic stationary phase occurs via hydrophobic interactions. It uses a stationary phase with hydrophobic ligands chemically bonded to a solid support. Polar mobile phases are used to elute retained solutes from the column. Key parameters that affect separation include the pH, ionic strength, and polarity of the mobile phase, use of gradients or isocratic elution, column length, and addition of ion-pairing agents. Reverse phase chromatography is commonly used to purify biomolecules like proteins, peptides, and nucleic acids.
Precipitation techniques can be used to recover proteins from liquid and remove unwanted byproducts like nucleic acids. Precipitation is usually induced by neutral salts, organic solvents, changing the pH to the isoelectric point, ionic or non-ionic polymers, metal ions, or heat treatment. The most common precipitating agent is ammonium sulfate, which causes proteins to aggregate and precipitate out of solution by restricting water availability and increasing hydrophobic interactions between proteins.
Sedimentation, Basic principle of sedimentation,Nomograph, Centrifugal force, Angular velocity, Type of rotars, Geometry of rotars,Types of centrifuge, calculation of centrifugal field, Safety measures for centrifuges.
Centrifugation is a process that uses centrifugal force to separate mixtures based on density differences. It works by spinning samples at high speeds, causing denser particles to sediment out of solution. There are two main types - preparative centrifugation which separates large amounts of samples, and analytical centrifugation which analyzes small amounts. Centrifugation has many applications including isolating suspensions, isotope separation, and separating cellular components.
Centrifugation is a process that uses centrifugal force to separate mixtures of substances based on density differences. It involves spinning a sample in a centrifuge which causes denser components to migrate outward while less dense components migrate inward. There are various types of centrifugation techniques used for separation in industrial and laboratory settings, including differential centrifugation, density gradient centrifugation, and ultracentrifugation. Centrifugation has many applications such as separating solids from liquids in water treatment, separating blood components, and separating particles in industrial processes.
Centrifugation is a technique used for the separation of particles from a solution according to their size, shape, density, viscosity of the medium and rotor speed. The particles are suspended in a liquid medium and placed in a centrifuge tube. The tube is then placed in a rotor and spun at a define speed.
Centrifugation is a process that uses centrifugal force to separate particles in a solution based on their density. It can be used to sediment particles, isolate cellular components like organelles, and separate molecules and complexes. Different types of centrifuges include low-speed, high-speed, and ultracentrifuges, which separate particles through differential centrifugation or density gradient centrifugation. Analytical centrifugation allows observation of fractionation processes and is used to study macromolecules. Centrifugation has various applications including concentration, separation, isolation of organelles, and separation of blood components or cream from milk.
The document provides an overview of centrifuges. It discusses the theory behind centrifugation and how centrifugal force allows for separation of particles based on size and density. It describes different types of centrifugation including preparative and analytical and separation techniques like differential centrifugation and density gradient centrifugation. The document also classifies centrifuges based on speed, rotor orientation, intended use, and construction. It outlines several functions centrifuges can perform including separation, clarification, classification, degritting, and thickening or concentration.
Ultracentrifuges spin liquid samples at extremely high speeds, up to 150,000 rpm, creating over 1 million times Earth's gravity. This strong centrifugal force causes denser materials to rapidly travel to the bottom of tubes. Ultracentrifuges are used to separate molecules and particles based on size and density. Common experiments include sedimentation velocity to analyze particle shape/size and sedimentation equilibrium to measure molecular weights. Ultracentrifuges find applications in biochemistry, such as isolating organelles, proteins, nucleic acids, and viruses.
Centrifugation principle and types by Dr. Anurag YadavDr Anurag Yadav
concept of cnetrifugation,
basic Principle
centrifugal force
types of centrifugation based on use and rotor type
application of the each type of centrifuge
Ultracentrifuge in detail
application in general
Centrifugation is a process that uses centrifugal force to separate mixtures based on density. Particles of different masses will settle at different rates in response to gravity when placed in a centrifuge. There are several types of centrifuges including low-speed, high-speed, and ultracentrifuges that can generate different centrifugal forces. Centrifugation techniques like density gradient centrifugation and differential centrifugation are used to separate components of a mixture based on properties like size, shape, and density. Centrifugation has many applications in clinical and research laboratories, such as separating blood components and isolating organelles or other cellular components.
A centrifuge operates by using the sedimentation principle- Here the substances are separated based on their density under the influence of gravitational force. When spun rapidly, lighter particles stay at the top and heavier particles go to the bottom during centrifugation.The components of heterogeneous mixtures are detached by centrifugation. That comprises liquids in liquids, solids in fluids, and gases in solids and liquids. In order to transfer bulky sections to the outside of the pipe, centrifugation uses centrifugal energy. It allows the solid to settle more easily and completely.The components of heterogeneous mixtures are detached by centrifugation. That comprises liquids in liquids, solids in fluids, and gases in solids and liquids. In order to transfer bulky sections to the outside of the pipe, centrifugation uses centrifugal energy. It allows the solid to settle more easily and completely.
What is the centrifuge used for?
Centrifuges work by separating out two materials with different densities. Centrifuges are used in various laboratories to separate fluids, gases or liquids based on density like the separation of different constituents of blood, immiscible liquids, wastewater sludge etc.
Centrifugation basic principle & theoryMayank Sagar
Centrifugation is a process used to separate or concentrate materials suspended in a liquid medium. It is a method to separate molecules based on their sedimentation rate under the centrifugal field. It involves the use of centrifugal force for the sedimentation of molecules.
A centrifuge uses centrifugal force to separate fluids or particles of different densities. It works by applying centrifugal acceleration, which causes denser particles to move outward in the radial direction while less dense particles move to the center. There are different types of rotors and centrifuges that separate particles based on properties like size, shape, density or sedimentation rate. Ultracentrifuges spin at very high speeds of over 100,000g to separate small particles like organelles, viruses and macromolecules.
Centrifugation is a separation technique that uses centrifugal force to separate mixtures based on density differences. It works by spinning samples at high speeds, causing denser components to sediment faster and separate out from less dense components. The basic components of a centrifuge are an electric motor to spin the samples and a rotor to hold the sample containers. There are different types of rotors and centrifugation techniques that separate samples based on factors like density, size, or sedimentation rate. Proper use and maintenance of centrifuges and rotors is important for safety and instrument lifespan.
Centrifugation is a procedure that uses centrifugal force to separate mixtures. Denser components move away from the axis of rotation while less dense components move towards the axis. The document discusses the principles, types (low speed, high speed, ultracentrifuges), applications, and techniques (preparative, differential, density gradient) of centrifugation. It provides details on rotor types, speeds, uses for separating organelles, macromolecules, and more. Diagrams illustrate basic centrifuge components and a table compares characteristics of different centrifuge types.
This presentation discusses centrifugation and different types of centrifuges. Centrifugation uses centrifugal force to separate mixtures based on properties like density. There are various types of centrifuges like benchtop, ultra, micro centrifuges that use different rotors and speeds. Centrifugation techniques include analytical centrifugation which separates based on density and size, density gradient centrifugation using gradients, and differential centrifugation for subcellular fractions. Centrifugation has applications in separating blood components, purifying cells and proteins, and separating mixtures in various fields.
A centrifuge is a device used to separate components of a mixture on the basis of their size, density, the viscosity of the medium, and the rotor speed.
The centrifuge is commonly used in laboratories for the separation of biological molecules from a crude extract.
In a centrifuge, the sample is kept in a rotor that is rotated about a fixed point (axis), resulting in strong force perpendicular to the axis.
There are different types of centrifuge used for the separation of different molecules, but they all work on the principle of sedimentation.
Centrifugation is a technique used to separate substances of different densities. It involves applying centrifugal force using a centrifuge, which spins samples at high speeds. This causes denser particles to sediment to the bottom of tubes while less dense particles rise to the top, allowing for separation. Centrifugation is used in processes like separating cream from milk, separating blood components, and purifying proteins and cells. It works on the principle that density differences between particles or molecules can be exploited to separate mixtures.
This document provides information about centrifugation and centrifuges. It defines centrifugation as using centrifugal force to separate mixtures based on density, with denser components moving away from the center of rotation. It describes how centrifugal force is calculated based on mass, angular velocity, and distance from the center. Different types of centrifuges and rotors are discussed, including clinical centrifuges, refrigerated centrifuges, ultracentrifuges, and rotors like fixed angle and swinging bucket rotors. Common applications and uses of centrifugation are also summarized.
Centrifugation uses centrifugal force to separate particles in a solution based on properties like size, shape, density. During centrifugation, a centrifuge spins the samples at high speeds, applying centrifugal force that causes more dense components to sediment away from the axis of rotation while less dense components migrate towards the axis. Different types of centrifuges exist for various applications, utilizing rotors that hold sample tubes at fixed angles or allow swinging buckets. Centrifugation is used across industries and in research/medical labs for tasks like separating blood components, purifying proteins and organelles, and producing density gradients for analytical separations.
Centrifugation uses centrifugal force to separate particles in suspension based on properties like size and density. It is used in processes like preparing blood samples and separating cellular components. There are different types of centrifuges like low-speed, high-speed refrigerated, and ultracentrifuges that can produce varying relative centrifugal forces. Rotors like swing-out, fixed angle, vertical, and zonal are used in preparative centrifuges for specific separations. Centrifugation, ultrafiltration, and lyophilization are important techniques used in biomedical research and industrial applications.
Centrifugation is a process that uses centrifugal force to separate mixtures based on density. It has been used since the 17th century and has evolved significantly. There are several types of centrifuges including low-speed, high-speed, ultracentrifuges, and more specialized types. Centrifugation principles involve applying centrifugal force to separate components based on size, density, viscosity, and rotor speed. It has many applications in science, medicine, and industry such as separating blood components, purifying proteins and viruses, and producing skim milk.
2. A centrifuge is a device that separates particles
from suspensions or even macromolecules from
solutions according to their size, viscosity of the
medium and density by subjecting these dispersed
systems to artificially induced gravitational fields by
rotor length and speed.
3. In a solution, particles whose density is higher than
that of the solvent sink (sediment), and particles that
are lighter than it float to the top.
The greater the difference in density, the faster they
move. If there is no difference in density (isopyknic
conditions), the particles stay steady.
To take advantage of even tiny differences in
density to separate various particles in a solution,
gravity can be replaced with the much more
powerful “centrifugal force”provided by a centrifuge.
4. A centrifuge is used to separate particles or
macromolecules :
-Cells
-Sub-cellular components
-Proteins
-Nucleic acids
Basis of separation:
-Size
-Shape
-Density
Methodology:
Utilizes density difference between the particles /
macromolecules and the medium in which these are
dispersed.
Dispersed systems are subjected to artificially induced
gravitational field
5. Separation (solid/liquid, solid/liquid/liquid and
solid/solid/liquid separation):
Centrifugation can be used for solid-liquid separation
provided the solids are heavier than the liquid.
Centrifuge can also be used to separate a heavy phase,
and two lighter liquid phases, with one of the lighter
phases being lighter than the other. Solids can be lighter
than liquid and separation is by flotation of the dispersed
solid phase.
6. Clarification- minimal solids in liquid product
Centrifuge can be used to clarify the discharged
separated lighter liquid phase. The objective is to
minimize the discrete suspendedsolids in the light
continuous phase. Usually, only fine submicron biosolids
are left uncaptured by centrifugation and they escape
with the discharged light phase.
Classification -sort by size and density
Centrifuge is used to classify solids of different sizes.
7. Degritting- remove oversized and foreign particles
Degritting is similar to classification where unwanted
particles, larger or denser, are rejected in the sediment,
with product (smaller or less dense) overflowing in the
lighter liquid phase. Another situation is where smaller
unwanted particles are rejected in the light liquid phase,
and valuable he avier solids are settled with the heavier
phase.
8. Thickening or concentration- remove liquid,
concentrate solids
Centrifuge is frequently used to concentrate the solid
phase by sedimentation and compaction, removing the
excess liquid phase in the overflow or concentrate. This
reduces the volume of the product in downstream
processing.
9. THE ANALYTICAL ULTRACENTRIFUGE:
The sedimentation coefficient of a particle may be
determined experimentally using an instrument
known as an analytical ultracentrifuge.
The rotor that spins in this ultracentrifuge typically
contains two compartments.
Into one compartment is placed a “reference cell”
containing sample-free solvent and the other re-
ceives a cell containing the sample to be analyzed.
The interior of each cell is sector shaped and
bounded above and below by parallel quartz
windows to permit light from below the rotor to pass
through the reference and sample during rotation.
10. THE ANALYTICAL ULTRACENTRIFUGE:
As the particles sediment, boundaries are formed at the trailing
edges of each particulate species. Changes in the distance
between each boundary and the axis of rotation are measured as
a function of time by the instrument’s optical system.
11. THE ANALYTICAL ULTRACENTRIFUGE:
These measurements are then used to calculate
the respective sedimentation coefficients of the
particles in the suspension.
The sedimentation coefficients of many cellular
macromolecules such as proteins and nucleic acids
fall in the range of 1 x 1013 to 200 x 1013 seconds
(i.e., the dimensions of s are seconds).
For convenience, a unit called the Svedberg unit
(named in honor of T. Svedberg), abbreviated S, is
used to describe sedimentation coefficients and is
equal to the constant 1013 seconds.
Thus, most cellular proteins have sedimentation
coefficients between 1 and 200 S.
12.
13. PREPARATIVE CENTRIFUGATION:
The counterpart to analytical centrifugation is pre-
parative centrifugation, which provides for the isola-
tion of cell components for further analysis.
14. PREPARATIVE CENTRIFUGATION:
Three basic types of
centrifuge rotors are regularly
employed for conventional
preparative centrifugation;
swinging-bucket rotors
fixed angle rotors
vertical rotors
Each category is designed to
address three key factors:
type of centrifugation
(differential, rate-zonal, or
isopycnic),
speed
volume range
15. SWINGING-BUCKET ROTORS
swinging-bucket rotors are the most common styles for
benchtop, low-speed, and high-speed floor-model
centrifuge applications.
The most common benchtop and super speed
centrifuge applications requiring a swinging-bucket
rotor include:
1. high-throughput protocols such as batch harvesting of
whole cells from growth media
2. high-capacity processing of blood collection tubes
3. large-volume tissue culture processing.
For these applications, the user can start with volumes
as large as 1000 mL and scale down to smaller
volumes of 1.5-mL conical tubes
16. SWINGING-BUCKET ROTORS
An ultracentrifuge equipped with a swinging-bucket
rotor can support both types of separations: rate-zonal
(i.e., based on mass or size) or isopycnic (i.e., based on
density).
For rate-zonal separations, a swinging-bucket rotor is
advantageous because the path length of the gradient
(i.e., distance from Rmin [inside top of meniscus] to
Rmax [outside bottom of tube]) is long enough for
separation to occur.
Since the buckets are positioned at 90° during the run
and returned to a vertical position at the end of the run,
the sample retains its orientation, which minimizes any
pellet or band disturbance.
18. FIXED-ANGLE ROTORS
Fixed-angle rotors are the most ubiquitous rotors used
in centrifugation.
The majority are used for basic pelleting applications
(differential separations), either to pellet particles from a
suspension and discard the excess debris, or to collect
the pellet.
The cavities in these rotors range in volume from 0.2
mL to 1 L, with speeds ranging from single digits to
1,000,000×g (relative centrifugal force, RCF).
19. FIXED-ANGLE ROTORS
Two factors determine the type of fixed-angle rotor
required:
1. desired g-force (RCF)
2. desired volume
Generally speaking, the size of the rotor is inversely
proportional to its maximum speed capability (i.e., the
larger the rotor, the lower the maximum speed).
20. FIXED-ANGLE ROTORS
An important specification when selecting a fixed-angle
rotor is the K factor, which indicates the pelleting
efficiency of the rotor at top speed, taking into account
the maximum and minimum radius (path length) of the
rotor cavity.
A low K factor indicates a higher pelleting efficiency;
therefore, the K factor can be a useful metric for
comparing the speed at which particles will pellet
across a range of rotors
21. VERTICAL ROTORS
Vertical rotors are fairly specialized—their most common use
is during ultracentrifugation for isopycnic separations,
specifically for the banding of DNA in cesium chloride.
In this type of separation, the density range of the solution
contains the same density as the particle of interest; thus the
particles will orient within this portion of the gradient.
Isopycnic separations are not dependent on the path-length
of the gradient but rather on run time, which must be
sufficient for the particles to orient at the proper position
within the gradient.
Vertical rotors have very low K factors (typically in the range
of 5–25), indicating that the particle must only travel a short
distance to pellet (or in this case form a band); therefore run
time is minimized.
22. DIFFERENTIAL CENTRIFUGATION
During centrifugation, particles sediment through the
medium in which they are suspended at rates related
to their size, shape, and density.
Differences in the sedimentation coefficients of the
various subcellular particles provide the means for
their effective separation.
23. DIFFERENTIAL CENTRIFUGATION
The material to be fractionated is subjected first to low-
speed centrifugation to sediment the largest (or
densest) particles present. Following this, the
unsedimented material (called the supernatant) is
transferred to another tube and centrifuged at a higher
speed (and usually also for a longer period of time) to
sediment particles of somewhat smaller size (and/or
lower density).
The sequence is repeated several times until all
particles have been sedimented; each sediment is
then used for further experimentation and analysis.
24. DIFFERENTIAL CENTRIFUGATION
The procedure that is routinely used for the differential fractionation of liver
tissue serves as a convenient example of this method.
25. DIFFERENTIAL CENTRIFUGATION
Differential
centrifugation has
several major
disadvantages.
Because the
homogenate is
initially distributed
uniformly
throughout the
centrifuge tube, the
first particles
sedimented will
necessarily be
contaminated with
small amounts of all
other constituents
of the homogenate.
26. DENSITY GRADIENT CENTRIFUGATION:
The resolution achieved during centrifugation can be
greatly improved if the mixture of particles is confined
at the outset to a narrow zone at the top of the
centrifuge tube and the particles then permitted to
sediment from this position.
Initial stability under these conditions can be obtained
only if the particles are layered onto a density
gradient, that is, a column of fluid of increasing
density.
If a particle reaches a position in the gradient where
the particle’s density and the gradient’s density are the
same then s becomes zero, and no further
sedimentation of the particle occurs.
This technique, known as density gradient
centrifugation.
27. DENSITY GRADIENT CENTRIFUGATION:
Density gradients may be stepwise (discontinuous) or
continuous.
A step gradient is prepared by successively layering
solutions of decreasing density in the centrifuge tube.
Continuous density gradients are prepared by mixing
dense and light solutions in varying proportions at a
controlled rate and delivering the mixture to a
centrifuge tube in a continuous stream.
28. DENSITY GRADIENT CENTRIFUGATION:
A linear gradient can be
made using a simple
equipment called gradient
maker, containing two
cylinder. One of the
cylinder contain lighter
solution while other filled
with denser one.
The lighter solution mixed
with the denser solution
while moving to the
centrifuge tube.
29. DENSITY GRADIENT CENTRIFUGATION:
Using this method, a
density gradient is formed
that decreases linearly as
a function of volume
between the limiting
densities originally
present in the two
cylinders.
30. DENSITY GRADIENT CENTRIFUGATION:
Additives used to provide solutions for density
gradients are selected on the basis of their solubility in
water and their compatibility with cells and subcellular
organelles.
the additive must form a solution within the required
density range
the additive must not interfere with, or damage, the
sample
the solvent must be compatible with the sample
the solution must have a refractive index within the
practical range, as well as a low viscosity
The additive must be easily removable from the
sample.
31. DENSITY GRADIENT CENTRIFUGATION:
Additives used to provide solutions for density
gradients are selected on the basis of their solubility in
water and their compatibility with cells and subcellular
organelles.
the additive must form a solution within the required
density range
the additive must not interfere with, or damage, the
sample
the solvent must be compatible with the sample
the solution must have a refractive index within the
practical range, as well as a low viscosity
The additive must be easily removable from the
sample.
32. DENSITY GRADIENT CENTRIFUGATION:
The additives for density gradient centrifugation can
be divided into four main categories:
Salts of Alkali Metals
Neutral Water Soluble Molecules
Hydrophilic Macromolecules
Synthetic Molecules
33. DENSITY GRADIENT CENTRIFUGATION:
These solutions fulfill most of the above requirements.
However, due to the high ionic strength, hydrogen bonding
within biological macromolecules (protein, nucleic acid -
protein complexes) is impaired by a chaotropic effect.
Therefore these salts are mainly used for DNA and RNA
separations.
Cesium chloride is used most frequently. Other useful salts
include sodium iodide, sodium bromide, cesium sulfate and
cesium acetate. Potassium tartrate has been used to
separate viruses from host cells.
It should be kept in mind that the density of the sample is
highly dependent on the hydration of the macromolecule,
which in turn depends to a large extent on the dehydration
power of the salt solution.
SALTS OF ALKALI METALS
34. DENSITY GRADIENT CENTRIFUGATION:
In this class of compounds sucrose is most widely
used. It has a useful density range of up to 1.29. This
range can be increased to 1.37 by addition of glucose
or by dissolving sucrose in D2O.
Sucrose has very little effect on macromolecules, but
affects enzyme activity. Due to its high osmotic
pressure, sucrose solution dehydrates cells and their
organellae very efficiently.
Glycerol solutions are the preferred media for the
separation of enzymes because they do not affect
enzyme activity. They exhibit a high viscosity, requiring
prolonged centrifugation times. More importantly
however, glycerol penetrates biological membranes.
NEUTRAL, WATER-SOLUBLE MOLECULES
35. DENSITY GRADIENT CENTRIFUGATION:
Dextran gradients have been used for the separation
of microsomes.
Separations achieved with dextrans show similar
results to those obtained by using synthetic sucrose/
epichlorohydrin co-polymers.
In some cases bovine serum albumin has been
applied, but the preparation of an appropriate solution
is very difficult.
HYDROPHILIC MACROMOLECULES
36. DENSITY GRADIENT CENTRIFUGATION:
Sucrose, Ficoll (a copolymer of sucrose and
epicholorhydrin), Metrizamide, Nycodenz, and Percoll
(a colloidal form of silica) are the most popular, as they
have minimal detrimental effects on organelles and
provide densities up to about 1.3 g/cm.
Cesium chloride, cesium trifluoroacetate, and other
dense salts are used when the limiting density must
be considerably higher (i.e., up to 1.9 g/cm).
38. DENSITY GRADIENT CENTRIFUGATION:
Density gradient centrifugation methods are of two
types, the rate zonal technique and the isopycnic
(isodensity or equal density) technique.
Rate Zonal Technique.
Isopycnic Technique
39. DENSITY GRADIENT CENTRIFUGATION:
When the densest region of a density gradient (i.e.,
the liquid at the bottom of the centrifuge tube) is less
dense than the particles being sedimented, all
particles will eventually reach the bottom of the tube (if
centrifugation is continued long enough).
However, if the duration of centrifugation is carefully
limited, this will not occur; instead, the particles will be
distributed through the density gradient in the order of
their sedimentation coefficient that depends on their
sizes and shapes.
Fractionations carried out in this manner are called
rate separations and are based on the combined
contributions of particle size and particle density.
RATE ZONAL TECHNIQUE
40. DENSITY GRADIENT CENTRIFUGATION:
A second density gradient technique, called equilibrium
density-gradient centrifugation is used to separate cellular
components on the basis of their density.
In this case the cellular mixture is centrifuged through a
steep density gradient that contains a high concentration of
sucrose, or more often, cesium chloride (CsCl).
In these gradients, the molecules being studied have a
density somewhere in between the highest and lowest
densities of sucrose or CsCl generated in the gradient.
The components of a sample begin to move down this
gradient in the same way as they do in a rate-zonal density
gradient. When a component of the mixture reaches a point
where the density of the solution is equal to its own density
(isopycnic), it stops moving further and forms a distinct
band.
ISOPYCNIC TECHNIQUE
41.
42. MOTOR
In general, centrifuge motors are high-torque, series-wound
DC motors, the rotation of which increases as the voltage is
increased. The rotor shaft is driven directly or through a gyro,
although occasionally a pulley system is used. Electrical
contact to the commutator is provided by graphite brushes,
which gradually wear down as they press against the
commutator turning at high speed, and thus should be
replaced at specified intervals.
43. MOTOR
Modern centrifuges have induction drive motors that have no
brushes to change. The shaft of the motor turns through
sleeve bearings located at the top and bottom of the motor.
Most instruments contain sealed bearings that are
permanently lubricated, while others require periodic
application of oil or grease.
The speed of the centrifuge
is controlled by a
potentiometer that raises
and lowers the voltage
supplied to the motor. The
calibrations on the speed
control are often only
relative voltage increments
and should never be taken
as accurate indicators of
speed. Therefore, periodic
recalibration is required.
44. IMBALANCE DETECTOR
Some instruments have an internal imbalance detector that
monitors the rotor during operation, causing automatic shutdown
if rotor loads are severely out of balance.
45. TACHOMETER
A tachometer indicates the speed in rpm. Most modern centrifuges use
electronic tachometers, in which a magnet rotates around a coil to produce a
current that can be measured.
The digital handheld tachometer is a gauge for determining speed, velocity
and distance. This handheld tachometer measures in two ways: either
optically and therefore without contact, or mechanically via various adapters.
In the optical measurement, a focused light beam is directed onto the
object andreflected back by a thin, reflective foil glued on the object with the
frequency of rotation. The result is displayed on the 5-digit LCD.
The distance between the handheld
tachometer and the measured object can
reach up to 600 mm. The mechanical
measurement of speed is performed with an
adapter tip that is placed on the axis of the
moving parts. For normal speed
or length measurement, a measuring wheel
is place on the adapter.
46. SAFETY LID
Modern centrifuges must have a door-locking mechanism to prevent the lid
from being opened while the instrument is running. If there is a power failure
or the safety latch fails for some reason it may be necessary to trip the door-
locking mechanism manually to retrieve the samples. Manufacturers’
instructions should be checked for the exact procedure required.
47. BRAKING SYSTEM
B raking devices are incorporated to provide rapid rotor deceleration. Modern
instruments have an electrical braking system that functions by reversing the
polarity of the electrical current to the motor. Other machines may have a
mechanical brake.
48. REFRIGERATOR
A centrifuge generates heat as it rotates and if samples are
temperature labile then a refrigerated centrifuge should be used.
Some centrifuges enable the rotor and chamber to be precooled
before a run
49. CENTRIFUGE TUBES
It is advisable to use a conical-bottomed tube in a swing-out bucket
rotor for the sedimentation of cells. This tube type will retain the pellet
of cells more effectively as the supernatant is removed. All tubes for
use with high-speed rotors are round-bottomed. Pyrex glass tubes
can withstand forces of around 2000 xg , while Corex tubes can be
used up to 12,000 xg.
Polycarbonate or polyallomer are the most common plastic tubes in
use but great care must be taken when using organic solvents.
Manufactur ers usually provide extensive information about solvent,
salt and pH resistance, as well as sterilisation procedures.
50. RELATIVE CENTRIFUGAL FORCE (F)
The force acting on a particle during centrifugation is given by
the equation
F = Mω2r
M = mass of particle
ω (omega) = Angular velocity of the spinning rotor in radians
per second (one unit of circumference contains 2π radians),
r = radius of rotation (distance of particles from axis of rotation
in cm)
𝜔 =
2𝜋 𝑟𝑒𝑣 𝑚𝑖𝑛−1
60
𝜔 =
2(3.1416) 𝑟𝑒𝑣 𝑚𝑖𝑛−1
60
𝜔 = 0.10472 × 𝑟𝑒𝑣 𝑚𝑖𝑛−1
51. RELATIVE CENTRIFUGAL FORCE (RCF)
The magnitude of the induced gravitational field is measured in terms
of the G value which is also referred to as the RCF (relative
centrifugal force) value depends on the rotation speed as well as the
manner in which the centrifuge tubes are held by the rotor.
𝐺 (𝑅𝐶𝐹) =
𝑟𝜔2
𝑔
r = distance from the axis of rotation (mm)
ω = angular velocity (radians/s)
g = acceleration due to gravity (m/s2)
𝐺 (𝑅𝐶𝐹) =
𝑟(0.10472 𝑥 𝑟𝑒𝑣 𝑚𝑖𝑛−1 )2
980
𝐺 (𝑅𝐶𝐹) =
𝑟(0.10472)2 𝑥 (𝑟𝑒𝑣 𝑚𝑖𝑛−1 )2
980
𝐺 (𝑅𝐶𝐹) = (𝑟 1.119𝑥10−5 𝑥 𝑟𝑒𝑣 𝑚𝑖𝑛−1 2)
52. RELATIVE CENTRIFUGAL FORCE (RCF)
What is the maximum relative centrifugal force applied when
red blood cells are sedimented at 1000 rpm in a rotor of
maximum sample radius equal to 10 cm?
RCFmax = 1.119 x 10-5 (1000)2(10)
= 1.119 x 102 or 112g
53. RELATIVE CENTRIFUGAL FORCE (RCF)
The RCF value can also be obtained using a nomogram. Using a straight-edged ruler,
line up the known rotating radius (distance from the center of the rotor to the bottom of
the centrifuge bucket) on the left with the known rpm on the far right and read the RCF
value where the line crosses the graph in the center.
nomogram..
55. RELATIVE CENTRIFUGAL FORCE (RCF)
Most manufacturers include a nomogram in the instruction manual;
however, most modern centrifuges now have the facility to swap the
figure displayed on the control panel between rpm and RCF,
making manual calculation unnecessary.
56. RELATIVE CENTRIFUGAL FORCE (RCF)
The sedimentation of particles by centrifugation is, in effect, a
method for concentrating them; therefore, one of the major
physical forces opposing such concentration is diffusion.
In the case of the sedimentation of cells or sub-cellular organelles
(nuclei, mitochondria, etc.), the effects of diffusion are essentially
nil.
However, when centrifugation is used to sediment much smaller
particles (such as cellular proteins, nucleic acids, or
polysaccharides), the effects of diffusion become significant.
57. SEDIMENTATION COEFFICIENT
The RCF or “g force” applied to particles during centrifugation is
independent of the physical properties of the particles being
sedimented. However, a particle’s sedimentation rate at a
specified RCF depends on the properties of the particle itself and
medium.
The instantaneous sedimentation rate of a particle during
centrifugation is determined by three forces.
FC, the centrifugal force,
FB, the buoyant force of the medium
FF, the frictional resistance to the particle’s movement
Two particles having different sizes or different densities can have
similar sedimentation coefficients. On the other hand, two particles
with either similar size or similar density can have markedly
different sedimentation coefficients.
58. SEDIMENTATION COEFFICIENT
The sedimentation coefficient s of a particle is used to
characterize its behavior in sedimentation processes.
The sedimentation coefficient has the dimention of a unit of time
and is expressed in svedbergs.
It is equal to 10-13 seconds and is written with no space between
the number and the symbol (e.g. 70S).
It is named after Theodor Svedberg (1884–1971), the Swedish
chemist who developed the technique of centrifugation for the
study of colloids and macromolecules, for which he was awarded
a Nobel Prize in 1926
Editor's Notes
See more at: http://www.biologydiscussion.com/cell-biology/centrifugation-theory-sedimentation-rate-coefficient-and-other-details/3558#sthash.Ok7F7O1o.dpuf
See more at: http://www.biologydiscussion.com/cell-biology/centrifugation-theory-sedimentation-rate-coefficient-and-other-details/3558#sthash.Ok7F7O1o.dpuf
See more at: http://www.biologydiscussion.com/cell-biology/centrifugation-theory-sedimentation-rate-coefficient-and-other-details/3558#sthash.Ok7F7O1o.dpuf
See more at: http://www.biologydiscussion.com/cell-biology/centrifugation-theory-sedimentation-rate-coefficient-and-other-details/3558#sthash.Ok7F7O1o.dpuf
The removed liver tissue is homogenized in cold buffer and centrifuged 10 minutes at 700 g. This is usually sufficient to sediment all the cell nuclei to the bottom of the centrifuge tube, thereby providing the nuclear fraction. Depending on the effectiveness of the homogenization procedure, some unbroken cells and large cell fragments may also be recovered in this fraction.
The overlying supernatant (called the nuclear supernatant) is removed and transferred to another tube for a second centrifugation at 20,000 g for 15 minutes. These sediments nearly all the mitochondria (i.e., the mitochondrial fraction).
Again, the supernatant (i.e., mitochondrial supernatant) is removed and is subjected to a third centrifugation at 105,000 g for 60 minutes. This causes the sedimentation of a fraction called microsomes, which includes ribosomes and small fragments of intracellular membranes.
The microsomal supernatant is referred to as the soluble phase of the cells, or cytosol, and includes soluble proteins, soluble nucleic acids, soluble polysaccharides, lipid droplets, and other minute particles. In the procedure just described the liver tissue is separated into four major fractions.
The instantaneous sedimentation rate of a particle during centrifugation is determined by three forces.
FC, the centrifugal force,
FB, the buoyant force of the medium
FF, the frictional resistance to the particle’s movement
The different components being separated by this technique are denser than any of the sucrose concentrations used in the gradient. Samples are, therefore, centrifuged just long enough to separate the components of interest. Longer centrifugation than necessary would allow all components to form a pellet at the bottom of the tube. One of the most important applications of this technique over the past decades was the separation of transfer RNA (4S) from ribosomal RNA that forms three different classes with distinct sedimentation values 23S, 16S and 5S. This helped to facilitate the characterization of the protein synthesizing system.