Automated pipetting robot for proxy high-throughput viscometry of Newtonian fluids

Abstract

In this work, we develop a high-throughput viscometer for Newtonian fluids with viscosities between 1500 and 12 000 cP. The viscometer is developed based on an automated pipetting robot Opentrons (OT-2), with a commercial wide bore tip. The measurement protocol exploits the known characteristics of air-displacement pipettes in dispensing and gravimetrically measuring fluids of different viscosities. Specifically, by measuring the actual dispense flow rate of fluids with varying viscosities under fixed dispense conditions, we construct a calibration curve and propose a scaling analysis based on flow through an idealized pipette tip geometry. Our model can predict the viscosity of Newtonian fluids with an error of 6.5%. We also showcase the flexibility of our platform by integrating a custom-design tip for a different viscosity range.