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Concept
Éprouvette graduée
Résumé
A graduated cylinder, also known as a measuring cylinder or mixing cylinder, is a common piece of laboratory equipment used to measure the volume of a liquid. It has a narrow cylindrical shape. Each marked line on the graduated cylinder represents the amount of liquid that has been measured.
Large graduated cylinders are usually made of polypropylene for its excellent chemical resistance or polymethylpentene for its transparency, making them lighter and less fragile than glass. Polypropylene (PP) is easy to repeatedly autoclave; however, autoclaving in excess of about (depending on the chemical formulation: typical commercial grade polypropylene melts in excess of ), can warp or damage polypropylene graduated cylinders, affecting accuracy.
A traditional graduated cylinder is usually narrow and tall so as to increase the accuracy and precision of volume measurement. It has a plastic or glass base (stand, foot, support) and a "spout" for easy pouring of the measured liquid. An additional version is wide and low.
Mixing cylinders have ground glass joints instead of a spout, so they can be closed with a stopper or connected directly with other elements of a manifold. With this kind of cylinder, the metered liquid does not pour directly, but is often removed using a Cannula. A graduated cylinder is meant to be read with the surface of the liquid at eye level, where the center of the meniscus shows the measurement line. Typical capacities of graduated cylinders are from 10 mL to 1000 mL.
Graduated cylinders are often used to measure the volume of a liquid. Graduated cylinders are generally more accurate and precise than laboratory flasks and beakers, but they should not be used to perform volumetric analysis; volumetric glassware, such as a volumetric flask or volumetric pipette, should be used, as it is even more accurate and precise. Graduated cylinders are sometimes used to measure the volume of a solid indirectly by measuring the displacement of a liquid.
Source officielle
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