This phenomenon has been intensively characterized for shake flask bioreactors. Under certain conditions the shaking process leads to a breakdown of liquid motion – called "out-of-phase phenomenon". 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. The shaking frequency has the most significant impact on oxygen transfer. The oxygen transfer rate in Erlenmeyer flasks depends on the agitation speed, the liquid volume, and the shake-flask design. 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. Erlenmeyer flasks used in cell culture are sterilized and may feature vented closures to enhance gas exchange during incubation and shaking. Microcystis floating colonies in an Erlenmeyer flask.Įrlenmeyer flasks are also used in microbiology for the preparation of microbial cultures. Their stamped volumes are approximate within about 5% accuracy. Like beakers, Erlenmeyer flasks are not normally suitable for accurate volumetric measurements. Hot vapors from the boiling solvent keep the filter funnel warm, avoiding the premature crystallization. The hot solution is filtered through a fluted filter paper into the receiving flask. The receiving flask is filled with a small amount of solvent, and heated to a boil. The sample to be purified is heated to a boil, and sufficient solvent is added for complete dissolution. The final two attributes of Erlenmeyer flasks make them especially appropriate for recrystallization. Erlenmeyer flasks' narrow necks can also support filter funnels. Hot vapour condenses on the upper section of the Erlenmeyer flask, reducing solvent loss. Such features similarly make the flask suitable for boiling liquids. 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 by placing it under the buret and adding solvent and the indicator in the Erlenmeyer flask. Method of swirling an Erlenmeyer flask during titration A Büchner flask is a common design modification for filtration under vacuum. Alternatively, the neck may be fitted with ground glass or other connector for use with more specialized stoppers or attachment to other apparatus. The mouth of the Erlenmeyer flask may have a beaded lip that can be stopped or covered. Depending on the application, they may be constructed from glass or plastic, in a wide range of volumes. It differs from the beaker in its tapered body and narrow neck. They may be graduated, and often spots of ground glass or enamel are used where they can be labeled with a pencil. Įrlenmeyer flasks have wide bases, with sides that taper upward to a short vertical neck. It is named after the German chemist Emil Erlenmeyer (1825–1909), who created it in 1860. An Erlenmeyer flask, also known as a conical flask ( British English) or a titration flask, is a type of laboratory flask which features a flat bottom, a conical body, and a cylindrical neck.
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