Guide to Pipette Maintenance

Accurate pipetting iscrucial for achieving accurate, reliable analyses. That’s why your pipettedeserves to be cared for.  

Choosing the right tip

• In liquid handling, the pipettor and the tip form a system and best results are naturally achieved when they have been developed together by the manufacturer. While there are many tip suppliers on the market, it is important to remember there is no such thing as a universal or standard tip. Being an integral component of the pipetting system, the tip’s shape, material properties and fit have a considerable influence on pipetting accuracy.
• The tip’s fit is also important. If the fitting is too loose, the pipettor might leak and could result in a 50% error in pipetting accuracy. 
• Calibration must be performed using the same shaped tip as for pipetting.  

Service and checking

• Pipettes are simple devices and do not actually need servicing more that once or twice a year. In fact, they are best left alone. However, regular checking is advised to identify any pipettes that are moving out of acceptable tolerances.

• The required frequency of checking can be determined using three simple questions:

1. What is the pipette used with? - Corrosive or non-corrosive liquids?
2. How well is the pipette looked after? - Is it stored vertically or horizontally?
3. How often is it used?

Some pipettes need checking every 2-4 weeks while others only need to be checked after 4-6 months.

• With the correct training, pipette checking can be carried out in the laboratory by the end user, calling on a service company only to rectify problem pipettes. A full service and calibration would then only be required 1-2 times a year..
• Leading pipette manufacturers state that seals and o-rings in their pipettes should last a minimum 100,000 operations. For the average pipette that means that the wearable parts should last an absolute minimum of 12 months.

Contamination of pipettes

• Good laboratory practice – pipetting slowly and carefully - minimises foaming and the formation of aerosols (tiny liquid droplets that remain suspended in the atmosphere for a long time). This is important to avoid contamination of the pipettor and the subsequent sample.

• As an additional precaution, aerosol-barriers tips have been introduced which incorporate a filter between the sample the pipettor. During pipetting, air flows through the filter, aimed to reduce the flow of aerosols or liquid into the pipettor barrel, and subsequently to the next sample (carryover contamination).
  

Should your pipette become contaminated, follow the manufacturer’s guidelines for cleaning the pipette or contact your pipette service company. A useful contact is Pipette Doctor , who deals with all makes of pipettes.