Pilot study: Intercomparison of ultra-low liquid flow rates in range below 100 nL/min

Project Description

Intercomparison to validate new primary standards for ultra-low liquid flow rates below 100 nL/min. This is part of Work Package 1 of EMPIR project 18HLT08 MeDDII, Metrology for Drug Delivery.

Final Report 2022-02-18

The project has been completed and the final report can be downloaded here>>.

In this comparison between the nine participants, static calibrations and dynamic calibrations were completed. In the static calibration, three different transfer standards were used. Two thermal flow meters and one syringe pump. For the dynamic calibration comparison, the two thermal flow meters were used.

The overall conclusion from this comparison exercise was that it was extremely successful and enabled the partners to share knowledge, improve their methodologies, evaluate their measurement uncertainties, and enhance their calibrations facilities. All participants succeeded in performing the evaluation with at least one Transfer Standard at several flow rates and to obtain results in line with the agreed protocol.

The results from the static calibrations were extremely promising and several laboratories achieved equivalency for at least two of the flow rates conducted with each of the three transfer standards

The results from the dynamic calibrations validate the traceability of the three laboratories that participated in the comparison. Whilst only three laboratories conducted the comparison for dynamic flow with both of the Transfer Standards, the results were extremely positive and further underpin the laboratory measurement uncertainty. All the calculated En values were less than 1.0 for the dynamic flow calibrations.