Fractionation is a

separation process A separation process is a method that converts a mixture or a solution of chemical substances into two or more distinct product mixtures, a scientific process of separating two or more substances in order to obtain purity. At least one product mi ...

in which a certain quantity of a

mixture In chemistry, a mixture is a material made up of two or more different chemical substances which can be separated by physical method. It is an impure substance made up of 2 or more elements or compounds mechanically mixed together in any proporti ...

(of gasses, solids, liquids,

enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

s, or

isotope Isotopes are distinct nuclear species (or ''nuclides'') of the same chemical element. They have the same atomic number (number of protons in their Atomic nucleus, nuclei) and position in the periodic table (and hence belong to the same chemica ...

s, or a suspension) is divided during a

phase transition In physics, chemistry, and other related fields like biology, a phase transition (or phase change) is the physical process of transition between one state of a medium and another. Commonly the term is used to refer to changes among the basic Sta ...

, into a number of smaller quantities (

fraction A fraction (from , "broken") represents a part of a whole or, more generally, any number of equal parts. When spoken in everyday English, a fraction describes how many parts of a certain size there are, for example, one-half, eight-fifths, thre ...

s) in which the

composition Composition or Compositions may refer to: Arts and literature *Composition (dance), practice and teaching of choreography * Composition (language), in literature and rhetoric, producing a work in spoken tradition and written discourse, to include ...

varies according to a

gradient In vector calculus, the gradient of a scalar-valued differentiable function f of several variables is the vector field (or vector-valued function) \nabla f whose value at a point p gives the direction and the rate of fastest increase. The g ...

. Fractions are collected based on differences in a specific property of the individual components. A common trait in fractionations is the need to find an optimum between the amount of fractions collected and the desired

purity Purity may refer to: Books * ''Pureza'' (novel), a 1937 Brazilian novel by José Lins do Rego * ''Purity'' (novel), a 2015 novel by Jonathan Franzen ** ''Purity'' (TV series), a TV series based on the novel *''Purity'', a 2012 novel by Jackson ...

in each fraction. Fractionation makes it possible to isolate more than two components in a mixture in a single run. This property sets it apart from other separation techniques. Fractionation is widely employed in many branches of science and technology. Mixtures of liquids and gasses are separated by

fractional distillation Fractional distillation is the separation of a mixture into its component parts, or fractions. Chemical compounds are separated by heating them to a temperature at which one or more fractions of the mixture will vaporize. It uses distillation ...

by difference in boiling point. Fractionation of components also takes place in

column chromatography Column chromatography in chemistry is a chromatography method used to isolate a single chemical compounds, chemical compound from a mixture. Chromatography is able to separate substances based on differential absorption of compounds to the adsorbe ...

by a difference in affinity between stationary phase and the

mobile phase In analytical and organic chemistry, elution is the process of extracting one material from another by washing with a solvent: washing of loaded ion-exchange resins to remove captured ions, or eluting proteins or other biopolymers from an el ...

. In fractional crystallization and

fractional freezing Fractional freezing is a process used in process engineering and chemistry to separate substances with different melting points. It can be done by partial melting of a solid, for example in zone refining of silicon or metals A metal ( ...

chemical substance A chemical substance is a unique form of matter with constant chemical composition and characteristic properties. Chemical substances may take the form of a single element or chemical compounds. If two or more chemical substances can be com ...

s are fractionated based on difference in solubility at a given temperature. In

cell fractionation In cell biology, cell fractionation is the process used to separate cell organelle, cellular components while preserving individual functions of each component. This is a method that was originally used to demonstrate the cellular location of vari ...

cell Cell most often refers to: * Cell (biology), the functional basic unit of life * Cellphone, a phone connected to a cellular network * Clandestine cell, a penetration-resistant form of a secret or outlawed organization * Electrochemical cell, a de ...

components are separated by difference in

mass Mass is an Intrinsic and extrinsic properties, intrinsic property of a physical body, body. It was traditionally believed to be related to the physical quantity, quantity of matter in a body, until the discovery of the atom and particle physi ...

Of natural samples

Bioassay-guided fractionation

A typical protocol to isolate a pure chemical agent from natural origin is step-by-step separation of extracted components based on differences in their

bioassay A bioassay is an analytical method to determine the potency or effect of a substance by its effect on animal testing, living animals or plants (''in vivo''), or on living cells or tissues (''in vitro''). A bioassay can be either quantal or quantit ...

-guided fractionation physicochemical properties, and assessing the

biological activity In pharmacology, biological activity or pharmacological activity describes the beneficial or adverse effects of a drug on living matter. When a drug is a complex chemical mixture, this activity is exerted by the substance's active ingredient or ...

, followed by next round of separation and assaying. Typically, such work is initiated after a given crude extract is deemed "active" in a particular in vitro assay.

Blood fractionation

The process of blood fractionation involves separation of blood into its main components. Blood fractionation refers generally to the process of separation using a centrifuge (

centrifugation 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 denser components of the mixture migrate ...

), after which three major blood components can be visualized: plasma, buffy coat and erythrocytes (blood cells). These separated components can be analyzed and often further separated.

Of food

Fractionation is also used for culinary purposes, as

coconut oil Coconut oil (or coconut fat) is an edible oil derived from the kernels, meat, and milk of the coconut palm fruit. Coconut oil is a white solid fat below around , and a clear thin liquid oil at higher temperatures. Unrefined varieties have a disti ...

palm oil Palm oil is an edible vegetable oil derived from the mesocarp (reddish pulp) of the fruit of oil palms. The oil is used in food manufacturing, in beauty products, and as biofuel. Palm oil accounted for about 36% of global oils produced from o ...

, and

palm kernel oil Palm kernel oil is an edible plant oil derived from the kernel of the oil palm tree ''Elaeis guineensis''. It is related to two other edible oils: ''palm oil'', extracted from the fruit pulp of the oil palm, and ''coconut oil'', extracted from ...

are fractionated to produce oils of different viscosities, that may be used for different purposes. These oils typically use fractional crystallization (separation by solubility at temperatures) for the separation process instead of distillation. Mango oil is an oil fraction obtained during the processing of mango butter.

Milk Milk is a white liquid food produced by the mammary glands of lactating mammals. It is the primary source of nutrition for young mammals (including breastfeeding, breastfed human infants) before they are able to digestion, digest solid food. ...

can also be fractionated to recover the

milk protein concentrate Milk protein concentrate (MPC) is any type of concentrated milk product that contains 40–90% milk protein. The United States officially defines MPC as "any complete milk protein (casein plus lactalbumin) concentrate that is 40 percent or more p ...

or the milk basic proteins fraction.

Of natural samples

Bioassay-guided fractionation

Blood fractionation

Of food

Isotope fractionation

See also

References

Further reading