Graduated pipets are commonly used in laboratory settings to accurately measure small volumes of liquid in microscale and miniscale reactions. They come in different sizes, such as 1.00 mL, 2.00 mL, 5.00 mL, and 10.00 mL, and two types: one that delivers its total capacity when the last drop is expelled, and the other that delivers its total capacity by stopping the delivery when the meniscus reaches the bottom graduation mark.
To fill the pipet, a pipet pump or syringe can be used. The pump should be selected to fit the size of the pipet. To fill the pipet, turn the knurled wheel in a direction that moves the piston up, drawing the liquid into the pipet. To expel the liquid, turn the wheel in the opposite direction. Alternatively, a syringe attached to the pipet with a short piece of latex tubing can also be used.
The most accurate volumes are obtained by difference measurement. This involves filling the pipet to a convenient specific mark and then discharging the liquid until the required volume has been dispensed. The volume contained in a graduated pipet is read from the bottom of the meniscus.
It is important to note that the excess liquid remaining in the pipet after dispensing the required volume should be placed in the appropriate waste container. This ensures that accurate measurements are obtained and avoids contamination of subsequent reactions.
Questions about graduated pipet:
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What are graduated pipets used for? Answer: Graduated pipets are used to measure small volumes of liquid accurately in microscale and miniscale reactions.
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What are the different types of graduated pipets? Answer: The two types of graduated pipets are one that delivers its total capacity when the last drop is expelled and the other that delivers its total capacity by stopping the delivery when the meniscus reaches the bottom graduation mark.
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How do you use a graduated pipet? Answer: To use a graduated pipet, fill it with liquid using a pipet pump or syringe, dispense the liquid until the required volume has been reached using difference measurement, and read the volume from the bottom of the meniscus.
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What is difference measurement in pipetting? Answer: Difference measurement is a technique used in pipetting to accurately measure small volumes of liquid by filling the pipet to a convenient specific mark and then discharging the liquid until the required volume has been dispensed.
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What is a pipet pump? Answer: A pipet pump is a device used to fill and dispense liquid from a graduated pipet.
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How do you choose the right pipet pump for a graduated pipet? Answer: The pipet pump should be selected to fit the size of the pipet being used.
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How do you dispose of excess liquid in a graduated pipet? Answer: Excess liquid remaining in the pipet should be placed in the appropriate waste container to prevent contamination of subsequent reactions.
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What is the most accurate way to measure volumes using a graduated pipet? Answer: The most accurate way to measure volumes using a graduated pipet is through difference measurement.
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How do you read the volume in a graduated pipet? Answer: The volume in a graduated pipet is read from the bottom of the meniscus.
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How do you prevent contamination when using a graduated pipet? Answer: To prevent contamination, it is important to properly dispose of excess liquid remaining in the pipet after dispensing the required volume.