Global standards such as GLP and ISO 8655-6 require pipette testing at defined intervals to ensure their proper functioning. However, in between these periodic checks, lab workers typically have little certainty that their pipettes are operating correctly.
Pipette accuracy checks reduce the potential for errors, but they are also time-consuming and resource intensive. However, convertible semi-micro balances such as the Mettler Toledo’s NewClassic MS105 are now available, combining weighing and pipette accuracy checking in the same easy-to-use instrument for reliable, reproducible results – and the cost savings that come with them.
The NewClassic MS105 converts easily from a laboratory balance with 0.01mg readability into a standalone pipette check-station: an evaporation trap is the only external device needed if the pipetting volume is smaller than 50μg. The trap keeps humidity levels stable during the check and thus minimises evaporation for accurate testing.
Since minute quantities cannot be measured directly, ISO8655-6 recommends distilled water for gravimetric capacity meter calibration. Distilled water is pipetted onto the balance and converted to a volumetric value. An application built into the balance firmware guides users through the check process. Systematic and random pipette errors are automatically calculated in absolute and relative values. Results are displayed and can be printed for traceability or for easy and quick comparison with the manufacturer’s tolerances.
Convertible balances such as the NewClassic MS are ideal for labs where more frequent accuracy checks – in between periodic required ISO standard calibrations – will provide added certainty that pipettes are still performing as expected.
