Resources

Practical technique

Essential knowledge should include:

• ensuring that the pipette is clean and free from contamination, e.g. oil film;
• knowing how to use a pipette filler correctly to draw-up liquid; adjust the volume and dispense the contents;
• knowing that the operating temperature should be consistent and close to the manufacturer’s specification (value is marked on the side of pipette);
• knowing the importance of ensuring that the temperature of the liquid being pipetted is similar to the pipette calibration temperature;
• knowing that it is essential to keep the tip of the pipette below the level of the liquid being drawn into the pipette;
• knowing how to check a glass pipette for damage, e.g. a broken tip, worn calibration line, etc.;
• knowing the need to condition glass pipettes, by rinsing with the sample before using to measure a particular volume
• knowing, when using a glass pipette, how to line up the bottom of the meniscus on the calibration line;
• knowing the importance of removing surplus liquid from the outside of a glass pipette (by wiping with a tissue);
• knowing to place the tip of the pipette onto the inner wall of the receiving vessel whilst draining;
• knowing how to check the time of outflow from the pipette against time indicated (usually marked on the pipette itself and related to delivery of water only);
• knowing how to use each manufacturers’ type of automatic pipette correctly;
• knowing how to choose an appropriate size and type of automatic pipette to dispense a particular liquid;
• knowing how to determine if the tip is fitted correctly onto the automatic pipette;
• knowing how to prevent solvent being drawn up into the body of an automatic pipette;
• knowing how to clean the mechanism of an automatic pipette and check its calibration;
• knowing that an automatic pipette must be kept upright if there is liquid in the pipette tip;
• knowing how to store pipettes when not in use, e.g. in a stand and upright.