• Skip to primary navigation
  • Skip to main content
  • Skip to primary sidebar

SBRU

  • Home
  • Documents & Resources
        • Protein Prep
          • Before you begin
          • Biochemistry & assays
          • Crystallography
          • Electrophoresis & gel staining
          • Immunoassays & immunological techniques
          • Liquid handling
          • Protein expression & cloning
          • Protein purification techniques
        • Chromatography
          • Affinity chromatography
          • Gel filtration chromatography
          • HPLC
          • Hydrophobic interaction chromatography
          • Ion-exchange chromatography
          • Reversed Phase chromatography
        • Manuals
          • All manuals
          • IMAGIC-5
          • “O”
          • Pymol
          • Spider
        • Other Resources
          • Student Resources
          • Useful Structural Biology Links
        • Book MCB Equipment

  • Structural Biology Coursework
  • Research Projects
  • People and Publications
  • About the SBRU
    • Events
    • MCB Bookings
    • Contact Us
    • Sitemap
You are here: Home / Structural Biology Coursework Modules / [GRD] Laboratory Techniques for Structural Biologists / Measuring Concentrations / Precision Volumetric Equipment

Precision Volumetric Equipment

pipetmanThe dispensing of small volumes of liquids with a high accuracy and repeatability is a routine operation in the bioscience laboratory. The equipment used for this purpose are costly precision instruments, which require careful handling. You will use the Gilson Pipetman® or the Labnet Biopette®, which allow one to deliver volumes down to 0.1 µl. The information below is adapted from the Gilson Pipetman manual. The operation of the Labnet Biopette is very similar.

The Gilson Pipetman

The Pipetman®, shown above, is a volumetric instrument designed to measure and transfer liquids precisely and safely. Eight different models are available, which cover a volume range from 0.1 μl to 10 ml

pipetman2

Construction

A diagram of the outer features of the Pipetman is shown on the left. The labels A-F refer to:

A: The push button (which is labelled with the maximum volume for the instrument).

B: A knurled knob by means of which the volume to be delivered may be adjusted. The volume is read on a digital volumeter.

C: The shaft, which may be autoclaved at for 20 minutes at 120 °C and 1 bar pressure. Do not attempt to dismantle the Pipetman! Get a staff member to assist you!

D: Disposable tip ejector (not found on P5000 and P10ml). This is activated by pressing on the button E.

F: Disposable polypropylene tip.

Top

Setting the volume

The volumeter consists of three numbers, and is read from top to bottom. The three numbers indicate the number selected. Note that the sequence of number indicate different volumes for each model.

pipetman3 pipetman6

The volume of the pipette is set by turning the black knurled adjustment ring (marked B in the above diagram).

To obtain maximum accuracy when changing the volumeter setting, follow the recommendations below:

  • When decreasing the volume setting, turn the adjustment ring slowly to reach the required setting, making sure not to overshoot the mark.
  • When increasing the volume setting, turn the adjustment ring until you are about1/3 turn above the required setting. Turn the adjustment ring slowly to decrease the volume to reach the desired setting, making sure not to overshoot the mark.
Top

Operation:

Place a suitable tip on the shaft of the pipette. Press the tip on firmly using a slight twisting motion to ensure a positive, airtight seal. Never handle a liquid with a Pipetman that has not been fitted with a tip.

pipetman7_original

Aspiration

  • Press the push button to the first positive stop (diagram A above).
  • Holding the pipette vertically, immerse the tip into the sample liquid. The depth to which the tip should be immersed in the sample liquid depends on the model
    • P2 and P10: 1 mm
    • P20 and P100: 2-3 mm
    • P200 and P1000: 3-6 mm
    • P5000: 3-6 mm P10ml: 5-7 mm
  • Release the pushbutton slowly and smoothly to aspirate the sample (diagram B above).
  • Wait one second and then withdraw the tip from the liquid. Wipe any droplets away from the outside of the tip using a tissue. Avoid touching the orifice of the tip..

Dispensing:

  • Place the end of the tip against the inside wall of the vessel at an angle of 10 to 40 degrees. Press the pushbutton smoothly to the first stop (diagram C above). Wait one second. Press the pushbutton to the second stop to expel any remaining liquid (diagram D above).
  • Keeping the pushbutton pressed to the end, remove the pipette by drawing the tip along the inside surface of the vessel.
  • Release the pushbutton (diagram E above).
  • Eject the tip by pressing the ejector button. It is only necessary to change the tip if a different liquid is being sampled or if the volumeter setting is changed.

Pre-rinsing

When pipetting liquids that have a viscosity and density different to water, for example, organic solvents, a film of liquid is formed on the inside wall of the pipette tip. The film can create an error. Since the film remains relatively constant in successive pipetting operations with the same tip, this error can be avoided by forming the film before dispensing the first sample. This is done by aspirating a sample and dispensing it into the same vessel. Since the film is already formed, all the following samples will have better accuracy and repeatability.

Top

Pipetman models:

Model

Volume range

Application

Typical Volumeter Reading

P2 0.1 – 2 μl Measurement and transfer of micro-volumes, DNA sequencing and enzyme assays P2
P10 0.5 – 10 μl P10
P20 2 – 20 μl Measurement and transfer of general aqueous solutions, acids and bases. P20
P100 20 – 100 μl P100
P200 50 – 200 μl P200
P1000 200 – 1 000 μl P1000
P5000 1 – 5 ml Measurement and transfer of large volumes. P5000
P10 ml 1 – 10 ml P10ml
Top

Disposable tips:

The Gilson polypropylene tips are chemically clean and may be autoclaved at 120 °C for 20 minutes at 1 bar pressure.

They come in different colours, as indicated in the table below… Note: The colour of the top of the pushbutton of the Pipetman corresponds to the colour of the tip that should be used.

Code

Volume range

For Pipetman model

C10 0.1 μl – 10 μl P2 – P10 pipetman5
C 20
(yellow)
2 μl – 200 μl P20 – P100
C200
(blue)
200 μl – 1 ml P1000
C5000
(Natural)
1 ml – 5 ml P5000
C10ml 1 ml – 10 ml P10ml
Top

References

Gilson Pipette documentation

  • Decontamination Procedures for Gilson Pipettes
  • Pipetman® P User Manual (2004)
  • Gilson Pipetman® Two Minute Inspection
  • Pipetman® Ultra Multichannel Brochure
  • Verification Procedure for Accuracy and Precision
Top

Primary Sidebar

Contact Us

021 650 2817
trevor.sewell@uct.ac.za

Copyright © 2025 · Genesis Sample on Genesis Framework · WordPress · Log in