Separate measurement of the density and viscosity of a liquid using a quartz crystal microbalance based on admittance analysis (QCM-A)

• Published in: Measurement science & technology 2011-01, Vol.22 (1), p.015402-015402
• Main Authors: Itoh, Atsushi, Ichihashi, Motoko
• Format: Article
• Language: English
• Subjects: Density; Ethyl alcohol; Liquids; Microorganisms; Quartz; Quartz crystals; Resonators; Viscosity
• ISSN: 0957-0233; 1361-6501
• DOI: 10.1088/0957-0233/22/1/015402

We previously used a quartz crystal microbalance (QCM) to identify a frequency f2 that allows measurement of the mass load without being affected by the viscous load of a liquid in the liquid phase. Here, we determined that frequency in order to separately measure the density and viscosity of a Newtonian liquid. Martin et al separately measured the density and viscosity of a liquid by immersing two quartz resonators, i.e. a smooth-surface resonator and a textured-surface resonator, in the liquid. We used a QCM based on admittance analysis (QCM-A) in the current study to separately measure the viscosity and density of a liquid using only a textured-surface resonator. In the current experiments, we measured the density and viscosity of 500 mu l of 10%, 30%, and 50% aqueous glycerol solutions and compared the measured values to reference values. The density obtained had an error of +/-1.5% of reference values and the viscosity had an error of about +/-5% of reference values. Similar results were obtained with 500 mu l of 10%, 30%, and 50% ethanol solutions. Measurement was possible with a quartz resonator, so measurements were made with even smaller samples. The density and viscosity of a liquid were successfully determined with an extremely small amount of liquid, i.e. 10 mu l, with almost the same precision as when using 500 mu l of the liquid.