An Erlenmeyer flask, also known as a conical flask (

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

) or a titration flask, is a type of laboratory flask which features a flat bottom, a conical body, and a cylindrical neck. It is named after the German chemist Emil Erlenmeyer (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 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 (mechanical), abra ...

. 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 ground glass or other connector for use with more specialized stoppers or attachment to other apparatus. A Büchner flask 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 filte ...

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 funnel A filter funnel is a laboratory funnel used for separating solids from liquids via the laboratory process of filtering. In order to achieve this, a cone-like shaped piece of filter paper is usually folded into a cone and placed within the funnel. ...

s. 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. 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. Like

beakers Beaker may refer to: Containers * Beaker (drinkware), a beverage container * Beaker (laboratory equipment), a glass container used for holding liquids in a laboratory setting * Beaker (archaeology), a prehistoric drinking vessel * Beaker culture ...

, 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 cultures. 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

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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