Highly Sensitive Measurement of Liquid Density in Air Using Suspended Microcapillary Resonators

We report the use of commercially available glass microcapillaries as micromechanical resonators for real-time monitoring of the mass density of a liquid that flows through the capillary. The vibration of a suspended region of the microcapillary is optically detected by measuring the forward scatter...

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Bibliographic Details
Main Authors: Oscar Malvar, Daniel Ramos, Carmen Martínez, Priscila Kosaka, Javier Tamayo, Montserrat Calleja
Format: Article
Language:English
Published: MDPI AG 2015-03-01
Series:Sensors
Subjects:
Online Access:http://www.mdpi.com/1424-8220/15/4/7650
Description
Summary:We report the use of commercially available glass microcapillaries as micromechanical resonators for real-time monitoring of the mass density of a liquid that flows through the capillary. The vibration of a suspended region of the microcapillary is optically detected by measuring the forward scattering of a laser beam. The resonance frequency of the liquid filled microcapillary is measured for liquid binary mixtures of ethanol in water, glycerol in water and Triton in ethanol. The method achieves a detection limit in an air environment of 50 µg/mL that is only five times higher than that obtained with state-of-the-art suspended microchannel resonators encapsulated in vacuum. The method opens the door to novel advances for miniaturized total analysis systems based on microcapillaries with the add-on of mechanical transduction for sensing the rheological properties of the analyzed fluids without the need for vacuum encapsulation of the resonators.
ISSN:1424-8220