Calibration of Equipment: Pipette Calibration

Good Laboratory Practices (GLP) must be kept in check for any laboratory environment. In the lab, there are some precise fluid volumes that need to be measured for dilution or transference of any kind. A pipette is the most helpful device in that regard but GLP dictates that equipment like pipette should undergo proper calibration procedures. This is why pipette calibration is a very essential step for any lab experiment or measurement procedure.

What is a Pipette?

Simply put, a pipette is a very important tool in the lab used for transport a measured liquid volume. Pipettes are pretty much used in all major scientific labs for medical testing, molecular biology and analytical chemistry. The levels of precision and designs all vary for pipettes depending on their usage and application. Various simple and complex designs are available. The most complex types of pipettes create a partial vacuum above the chamber that holds the liquid. Micropipettes dispense only around 1 to 1000 l while macro-pipettes deliver a much larger quantity.

Types of Pipette

Various types of pipettes exist including piston-driven air-displacement pipettes and positive-displacement pipettes which are micropipettes; volumetric or graduated pipettes which are large capacity pipettes. Air-displacement pipettes have further varieties that include adjustable or fixed, volume handled, Single-channel, multi-channel or repeater, conical tips or cylindrical tips, standard or locking and manual or electronic. Positive-displacement pipettes are less common and used generally for important substances like DNA. Mohr pipettes and serological or blow-out pipettes are examples of Graduated pipettes. Pipette calibration varies from one pipette to another.

Pipette Calibration

In order to ensure high quality standards for a laboratory calibration of equipment is very important. This is the process through which the quality of a measuring device can be adjusted by comparison with a standard device. Any form of pipette calibration will provide assurance for the precise working of an instrument like pipette. It is a complex issue to tackle because calibration ultimately depends on pipette models as well as several other factors like accuracy and precision of liquid volumes required, operator training applications and various additional external factors. Most companies will give their equipment to a third party calibrator.

When Should Pipette Calibration Take Place?

So when should you give your instrument or pipette in this case, for calibration? Well the answer to that isnt simple because really, it depends on a number of factors. The sooner a pipette gets affected by inaccuracy the sooner it requires some kind of calibration and this time period depends not only on the make and model of the pipette but also on the training and expertise of the operator.

Other factors that must be taken into consideration would be temperature, humidity, heat transference, operator fatigue, type of liquid being dispensed, accuracy and precision required and the amount of wear and tear inflicted on the pipette. All this collectively will determine when you should opt for pipette calibration. As a general rule, pipette calibration is required every six months but calibration of equipment is required every four months if the institution is regulated by GMP/GLP or FDA regulations.