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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

NEAR-INFRARED IMAIGING OF REACTION AND DIFFUSION PHENOMENA OF AQUEOUS SOLUTIONS IN MICROFLUDIC CHANNEL

Get access (open in a dialog) DOI: 10.1615/IHTC16.nmt.023920
pages 7315-7322

Abstract

In recent years, chemical analyses/syntheses using microfluidic chips, or microreactors, have been vigorously studied because it is possible to precisely control chemical reactions between very small amounts of samples. For the design and evaluation of microreactors, it is important to measure concentration distributions of target substances in liquid and to quantify their generation or reduction during chemical reactions. We have thus developed a concentration imaging method for aqueous solutions, based on the near-infrared (NIR) absorption characteristic of water. This method needs to add no substance to the aqueous solutions and can be applied to various aqueous solutions. Moreover, a great advantage of this method is to measure the concentrations of multiple substances simultaneously. In this study, when the aqueous solutions of HCl and NaOH were flowed in parallel through a microfluidic channel, the concentration distribution of HCl, NaOH, and NaCl were measured by the NIR-based imaging method, where three wavelengths of 1412 nm, 1442 nm, and 1520 nm in the ν1 + ν3 absorption band of water were used. The concentration images indicated the generation of NaCl by neutralization reaction and the interdiffusion processes of HCl and NaOH.