An Erlenmeyer flask, also known as a conical flask (

British English British English (BrE, en-GB, or BE) is, according to Oxford Dictionaries, "English as used in Great Britain, as distinct from that used elsewhere". More narrowly, it can refer specifically to the English language in England, or, more broadl ...

) or a titration flask, is a type of

laboratory flask Laboratory flasks are vessels or containers that fall into the category of laboratory equipment known as glassware. In laboratory and other scientific settings, they are usually referred to simply as flasks. Flasks come in a number of shapes and ...

which features a flat bottom, a conical body, and a cylindrical neck. It is named after the German chemist

Emil Erlenmeyer Richard August Carl Emil Erlenmeyer (28 June 182522 January 1909), known simply as Emil Erlenmeyer, was a German chemist known for contributing to the early development of the theory of structure, formulating the Erlenmeyer rule, and designing ...

(1825–1909), who created it in 1860. Erlenmeyer flasks have wide bases, with sides that taper upward to a short vertical neck. They may be graduated, and often spots of

ground glass Ground glass is glass whose surface has been ground to produce a flat but rough (matte) finish, in which the glass is in small sharp fragments. Ground glass surfaces have many applications, ranging from ornamentation on windows and table glassw ...

or enamel are used where they can be labeled with a

pencil A pencil () is a writing or drawing implement with a solid pigment core in a protective casing that reduces the risk of core breakage, and keeps it from marking the user's hand. Pencils create marks by physical abrasion, leaving a tra ...

. It differs from the beaker in its tapered body and narrow neck. Depending on the application, they may be constructed from glass or plastic, in a wide range of volumes. The mouth of the Erlenmeyer flask may have a beaded lip that can be

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ed or covered. Alternatively, the neck may be fitted with

or other connector for use with more specialized stoppers or attachment to other apparatus. A

Büchner flask A Büchner flask, also known as a vacuum flask,The use of the term ''vacuum flask'' sometimes causes confusion with the Thermos flask filter flask, suction flask, side-arm flask, Kitasato flask or Bunsen flask, is a thick-walled Erlenmeyer flas ...

is a common design modification for

filtration Filtration is a physical separation process that separates solid matter and fluid from a mixture using a ''filter medium'' that has a complex structure through which only the fluid can pass. Solid particles that cannot pass through the filter ...

under vacuum.

Uses

In chemistry

The slanted sides and narrow neck of this flask allow the contents of the flask to be mixed by swirling, without risk of spillage, making them suitable for

titrations Titration (also known as titrimetry and volumetric analysis) is a common laboratory method of quantitative chemical analysis to determine the concentration of an identified analyte (a substance to be analyzed). A reagent, termed the ''titrant'' ...

by placing it under the buret and adding solvent and the indicator in the Erlenmeyer flask. Such features similarly make the flask suitable for boiling liquids. Hot vapour condenses on the upper section of the Erlenmeyer flask, reducing

solvent A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...

loss. Erlenmeyer flasks' narrow necks can also support filter funnels. The final two attributes of Erlenmeyer flasks make them especially appropriate for recrystallization. The sample to be purified is heated to a boil, and sufficient solvent is added for complete

dissolution Dissolution may refer to: Arts and entertainment Books * ''Dissolution'' (''Forgotten Realms'' novel), a 2002 fantasy novel by Richard Lee Byers * ''Dissolution'' (Sansom novel), a 2003 historical novel by C. J. Sansom Music * Dissolution, in mu ...

. The receiving flask is filled with a small amount of solvent, and heated to a boil. The hot solution is filtered through a fluted filter paper into the receiving flask. Hot vapors from the boiling solvent keep the filter funnel warm, avoiding the premature

crystallization Crystallization is the process by which solid forms, where the atoms or molecules are highly organized into a structure known as a crystal. Some ways by which crystals form are precipitating from a solution, freezing, or more rarely deposi ...

. Like beakers, Erlenmeyer flasks are not normally suitable for accurate volumetric measurements. Their stamped volumes are approximate within about 5% accuracy.

In biology

Erlenmeyer flasks are also used in

microbiology Microbiology () is the scientific study of microorganisms, those being unicellular (single cell), multicellular (cell colony), or acellular (lacking cells). Microbiology encompasses numerous sub-disciplines including virology, bacteriology, ...

for the preparation of

microbial culture A microbiological culture, or microbial culture, is a method of multiplying microbial organisms by letting them reproduce in predetermined culture medium under controlled laboratory conditions. Microbial cultures are foundational and basic diagn ...

s. Erlenmeyer flasks used in cell culture are sterilized and may feature vented closures to enhance gas exchange during incubation and shaking. The use of minimal liquid volumes, typically no more than one fifth of the total flask volume, and baffles molded into the flask's internal surface both serve to maximize gas transfer and promote chaotic mixing when the flasks are orbitally shaken. The oxygen transfer rate in Erlenmeyer flasks depends on the agitation speed, the liquid volume, and the shake-flask design. The shaking frequency has the most significant impact on oxygen transfer. Oxygenation and mixing of liquid cultures further depend on rotation of the liquid "in-phase", meaning the synchronous movement of the liquid with the shaker table. Under certain conditions the shaking process leads to a breakdown of liquid motion – called "out-of-phase phenomenon". This phenomenon has been intensively characterized for shake flask bioreactors. Out-of-phase conditions are associated with a strong decrease in mixing performance, oxygen transfer, and power input. Main factor for out-of-phase operation is the viscosity of the culture medium, but also the vessel diameter, low filling levels and/or a high number of baffles.

Legal restriction

To impede illicit drug manufacturers, the state of

Texas Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by ...

previously restricted the sale of Erlenmeyer flasks to those who have the requisite permits. On September 1, 2019, SB 616 amended the law so that permits are no longer required, but accurate inventory of this and certain other pieces of lab equipment must still be maintained, loss or theft must still be reported, and the owner must still allow audits of their records and equipment to be made.

Additional images

File:Matraz de Erlenmeyer - Diseño original.png, Original drawing of the Erlenmeyer flask File:Erlenmeyer flasks en.svg, Different styles Erlenmeyer flasks File:Erlenmeyer flask ben.jpg, Different sizes of Erlenmeyer flask File:Autoclaved sterile Erlenmeyer flasks.jpg, Autoclaved sterile Erlenmeyer flasks covered with aluminium foil

References