Malvar Oscar, Ramos Daniel, Martínez Carmen, Kosaka Priscila, Tamayo Javier, Calleja Montserrat
Institute of Microelectronics of Madrid (IMM-CSIC), Isaac Newton 8 (PTM), Tres Cantos, 28760 Madrid, Spain.
Sensors (Basel). 2015 Mar 30;15(4):7650-7. doi: 10.3390/s150407650.
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.
我们报告了使用市售玻璃微毛细管作为微机械谐振器，用于实时监测流经毛细管的液体的质量密度。通过测量激光束的前向散射来光学检测微毛细管悬浮区域的振动。针对乙醇与水、甘油与水以及曲拉通与乙醇的液体二元混合物，测量了填充液体的微毛细管的共振频率。该方法在空气环境中的检测限为50µg/mL，仅比封装在真空中的最先进的悬浮微通道谐振器所获得的检测限高五倍。该方法为基于微毛细管的微型全分析系统带来了新进展，通过增加机械传感来检测被分析流体的流变特性，而无需对谐振器进行真空封装。
