Using and looking after your pipettes correctly is paramount to maintaining accuracy and achieving repeatable and reproducible results. Dispensing of precise volumes of liquid is but one step in a workstream and often an essential activity within protocols. The pipette has hidden complexities for an instrument that looks so simple in design, and yet if it is used properly it can be precise on a microscopic level, delivering to a specified nominal volume. It is no surprise, therefore, that international standard ISO 8655 dictates design requirements, calibration procedures, and possible sources of error when pipetting. Once a pipette has been calibrated correctly it is important to maintain Good Pipetting Practice in order to avoid inaccuracies and to service each pipette at least once a year to guarantee that you can standardise the delivery of a precise volume. Servicing also extends your pipettes’ lifespan, helps you to avoid poor performance and leakages, and eliminates cross contamination. In order to help make your pipetting experience more comfortable this article focusses on some top tips.
Get started - Ergonomics of your work station
Get organised so that your area is laid out in zones. The closest items should be those that you intend to use constantly, such as tips and pipettes. Reagents should be place further afield, and gloves or tubes even further away still. You should also consider adjusting your chair to a correct height so that you can pipette comfortably with your elbow resting on the bench. Also, be sure to take short breaks to prevent fatigue and repetitive strain injuries.
Tailor your pipetting style
Whatever your pipetting style start by ensuring that your pipette is clean by wiping it with 70% ethanol, and then choose your technique based on your sample to ensure accuracy.
Keep a consistent aspirate/dispense rhythm; hold the pipette vertically when aspirating; pre-rinse, where possible, the tip in the liquid to be pipetted; immerse the tip to the correct depth; place the end of the tip against the inside wall of the vessel when dispensing; and maintain a constant environment.
Take care of your pipette, so it takes care of your samples
After you have finished pipetting it is good to get into the practice of storing it upright and putting a maintenance plan into action. Look after your pipette by checking and cleaning the shaft, seal and piston regularly. When pipetting take care not to force the volume setting higher than the maximum, avoid bumping or dropping it, and take care when mounting tips. After 6-12 months of pipetting it is important to ensure that pipettes are serviced and calibrated in accordance with ISO 8655-6. This can be undertaken professionally and should be done by a well-established pipetting service. The Cole-Parmer Kinesis® Pipette Services has over 20 years’ experience in the calibration, repair & servicing of all manufacturers’ single, multi-channel, manual & electronic pipettes, in accordance with ISO 8655-6. The laboratories work to the widest accreditation schedule from 0.1µl to 100ml, and perform a complete operation assessment, examination of all internal and external parts, and overhaul the sealing system in accordance with manufacturers’ procedures, whilst using genuine parts.