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Efficiency in variable pipetting

Handling of air-interface pipettes

Aspirate sample

Pipetting: Adjust volume

  • Adjust volume
  • Use the correct tip(s) according to the volume range (Color-Code)
  • Press the pipetting button to the first stop and keep the button pressed
  • Immerse the pipette tip(s) 2 to 6 mm into the liquid (depending on volume)
  • Let the pipetting button slide back slowly while holding the pipette in an upright position (the liquid will be aspirated)

Discharge sample

Pipetting: Discharge sample

  • Place the pipette tip(s) against the wall of the receiving vessel
  • Press the pipetting button slowly and evenly down to the second stop (over-stroke) to empty the tip(s) completely
  • Ensure while discharging the sample that the tip(s) are not immersed into the liquid that might be in the receiving vessel
  • Wipe the pipette tip(s) against the receiving vessel wall over a distance of approx. 10 mm

Ejecting the tip(s)

Pipetting: Ejecting the tip(s)

  • Keep the pipetting button pressed while removing the pipette from the receiving vessel
  • Let the pipetting button slide back slowly
  • Press the tip ejection key to remove the tip(s)
  • Correctly dispose of pipette tip(s)
  • Store the pipette in an upright position when not in use (VITLAB® bench top rack/ shelf mount)

Optimal pipetting

For exact and precise analytical results, the following points should be considered, independent of the pipetting technique:

  • The best results are obtained with pipette tips that are recommended by the manufacturer, since only they have been checked for an optimal fit with the pipette.
  • A second important factor that can influence the analytical result is the quality of the tip material. VITLAB® pipette tips are manufactured from high quality polypropylene.
  • Pipette tips are intended for single-use only. Reuse and cleaning of used pipette tips should be avoided because it can influence accuracy and lead to cross-contamination of samples.
  • The pipette should be held vertically while as- pirating the sample because an increase in the
    angle of inclination can result in volume errors.
  • To obtain optimal results, the immersion depth of the tip should only be a few millimetres (de-
    pending on volume).
  • The air-interface between piston and sample should be kept as small as possible. The smaller the air-interface the higher is the accuracy of the result. The color-code helps with the selection of the fitting pipette tip.

Forward pipetting

Pipetting: Forward pipetting
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Reverse pipetting

The reverse pipetting technique should be used to pipet viscous solutions, wetting solvents or media with high vapour pressure with air-interface pipettes. In contrast to forward pipetting, the reverse pipetting technique is as follows:

Pipetting: Reverse pipetting
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