Pipettes and Tips Information
Pipettes and tips are used for accurate liquid handling in many lab applications. They are either of the classical style (glass) or digital.
This area includes both pipettors, which are complete devices used to deliver a known quantity of solution to a vessel; and pipette tips, through which fluids are dispensed, which are often sold separately from the pipette or pipettor.
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There are three main types of pipettes and tips: Pasteur, positive displacement, and air displacement.
Pasteur pipettes are small glass tubes with a bulb at the end used for dispensing small amounts of fluids. Both Pasteur and positive displacement types of pipettes have a piston that moves in a cylinder, or capillary.
In air displacement pipetting, a specified volume of air remains between the piston and the liquid. Typically, air displacement pipettes are meant for general use with aqueous solutions.
Selecting air displacement pipettes and tips require special consideration. Air displacement pipetting, which is used for standard pipetting applications, is highly accurate. Even so, conditions such as atmospheric pressure, and the specific gravity and viscosity of the solution can have an effect on the performance of air displacement pipettes.
In positive displacement pipetting, the piston is in direct contact with the liquid. Positive displacement pipettes are used for high viscosity and volatile liquids. Positive displacement pipettes and tips are also used for high viscosity and volatile liquids.
Positive displacement pipettes and tips are used in applications that require extreme accuracy. These pipettes and tips are also recommended for specialized procedures such as DNA amplification. The microsyringe tips used in positive displacement pipettes are disposable, which helps avoid sample-to-sample and cross-contamination, and contamination due to the aerosol effect.
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