title: Highly sensitive measurement of liquid density in air using suspended microcapillary resonators.
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.
authors.affiliation: Institute of Microelectronics of Madrid (IMM-CSIC), Isaac Newton 8 (PTM), Tres Cantos, 28760 Madrid, Spain. oscar.malvar@csic.es.
authors.forename: Oscar
authors.initials: O
authors.lastname: Malvar
authors.affiliation: Institute of Microelectronics of Madrid (IMM-CSIC), Isaac Newton 8 (PTM), Tres Cantos, 28760 Madrid, Spain. daniel.ramos@csic.es.
authors.forename: Daniel
authors.initials: D
authors.lastname: Ramos
authors.affiliation: Institute of Microelectronics of Madrid (IMM-CSIC), Isaac Newton 8 (PTM), Tres Cantos, 28760 Madrid, Spain. carmen.martinez.d@csic.es.
authors.forename: Carmen
authors.initials: C
authors.lastname: Martínez
authors.affiliation: Institute of Microelectronics of Madrid (IMM-CSIC), Isaac Newton 8 (PTM), Tres Cantos, 28760 Madrid, Spain. priscila@imm.cnm.csic.es.
authors.forename: Priscila
authors.initials: P
authors.lastname: Kosaka
authors.affiliation: Institute of Microelectronics of Madrid (IMM-CSIC), Isaac Newton 8 (PTM), Tres Cantos, 28760 Madrid, Spain. jtamayo@imm.cnm.csic.es.
authors.forename: Javier
authors.initials: J
authors.lastname: Tamayo
authors.affiliation: Institute of Microelectronics of Madrid (IMM-CSIC), Isaac Newton 8 (PTM), Tres Cantos, 28760 Madrid, Spain. mcalleja@imm.cnm.csic.es.
authors.forename: Montserrat
authors.initials: M
authors.lastname: Calleja
mesh_terms: D057230:Limit of Detection; D012212:Rheology / Q000295:instrumentation*
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