Smallest Volume for Pipette Calibration Capability Published
Artel is pleased to announce that its technology was used in a project comparing the photometric and gravimetric methods for micropipette calibrations. Dr. Elsa Batista at the Portuguese National Metrology Institute (IPQ) led the study in the EURAMET Technical Committee for Flow, with participation of Artel’s metrology experts. The photometric method used by Artel’s PCS Pipette Calibration System achieved superior results at pipetted liquid volumes between 0.1 and 100 microliters compared to the more commonly used gravimetric system. Use of the PCS technology allowed IPQ to become the first National Metrology Institute worldwide to publish a Calibration and Measurement Capability (CMC) for volume measurements of 0.1 microliters. This is the smallest volume for which a CMC is reported in the BIPM (Bureau International des Poids et Mesures) key comparison database.
“When undertaking the project of comparing micropipette calibration methods, IPQ needed technology that could deliver results with the lowest possible level of measurement uncertainty,” according to Doreen Rumery, Laboratory Technical Manager, Artel. “Using Artel’s photometric PCS technology enabled IPQ to achieve and validate the CMC for the smallest reported calibration volume and be able to publish it on the BIPM website.”
IPQ utilized the photometric method, which employs a high-resolution photometer for colorimetric analysis to determine the volume dispensed by a micropipette. In volume measurements of 0.1 microliters, the photometric method results in about 2% overall measurement uncertainty, while the gravimetric method resulted in up to 30% measurement uncertainty. The large gravimetric uncertainty was primarily due to balance error. The reduced uncertainty of the photometric method revealed the actual volumetric performance of the micropipette. The study concluded that the photometric method used in the Artel PCS is the superior choice for obtaining reliable and repeatable results when working with smaller volumes.
IPQ and Artel will continue their cooperation to make process improvements in the field of volume measurement.