Since pipettes are such as crucial tool in any laboratory, keeping them properly calibrated is essential. If you don't, your uncalibrated pipettes could lead to inaccurate test results and penalties for ISO noncompliance (including losing your certification). However, not all calibration is equal; on-site calibration services is often the most affordable option, but its potential for inaccuracy makes it a poor choice.
While the equipment used to calibrate your pipettes has the biggest impact on the accuracy of the calibration, it's not the only factor that affects the outcome. The environment they're calibrated in can also interfere with the accuracy. That's why off-site calibration is almost always the best way to ensure your pipettes are measuring and transferring fluids precisely.
If you're wondering what makes off-site calibration services superior, take a look at these 2 ways your on-site environment can lead to improperly calibrated pipettes.
Uncontrolled Heat and Moisture
One of the biggest environmental factors that impacts on pipette calibration is uncontrolled heat. If your pipettes are calibrated on-site in a room that's too warm, for example, fluids may start to evaporate. This leads to incorrect volume measurements, giving you an allegedly calibrated pipette that's actually inaccurate. It's not just dry heat that's a problem, though — humidity can also be an issue.
A warm and moist environment will interfere with volume measurements when your pipettes are being calibrated because the air inside them will absorb the humidity and expand. Since your site's environment is set up for your specific laboratory activities rather than calibration services, it's very difficult to make sure you have the right conditions during on-site calibration. Off-site calibration, on the other hand, takes place in an atmosphere that has temperature and humidity controlled with calibration in mind.
Uncontrolled Airflow and Vibration
Alongside the environmental factors that affect the pipettes themselves, on-site calibration can also be inaccurate because of factors that affect the calibration equipment itself. Vibrations and air currents, in particular, are the culprit. Since pipette calibration tools must be highly sensitive in order to give the most accurate readings, even the smallest of movements can mess with the calibration process.
Someone brushing past the table the equipment is sat on, for example, could throw your pipette accuracy off balance. Off-site calibration centres don't have this problem because they're designed and furnished to minimise movement. Calibrators often use very heavy marble tables and specially-made chairs that ensure no detectable motion can interfere with their tools.