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

Author： Malvar Oscar Ramos Daniel Martínez Carmen Kosaka Priscila Tamayo Javier Calleja Montserrat

Publisher： MDPI

E-ISSN： 1424-8220|15|4|7650-7657

ISSN： 1424-8220

Source： Sensors, Vol.15, Iss.4, 2015-03, pp. : 7650-7657

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Abstract

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.