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Mapping the Salinity Gradient in a Microfluidic Device with Schlieren Imaging

This work presents the use of the schlieren imaging to quantify the salinity gradients in a microfluidic device. By partially blocking the back focal plane of the objective lens, the schlieren microscope produces an image with patterns that correspond to spatial derivative of refractive index in the...

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Autores principales: Sun, Chen-li, Chen, Shao-Tuan, Hsiao, Po-Jen
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4482010/
https://www.ncbi.nlm.nih.gov/pubmed/26007720
http://dx.doi.org/10.3390/s150511587
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author Sun, Chen-li
Chen, Shao-Tuan
Hsiao, Po-Jen
author_facet Sun, Chen-li
Chen, Shao-Tuan
Hsiao, Po-Jen
author_sort Sun, Chen-li
collection PubMed
description This work presents the use of the schlieren imaging to quantify the salinity gradients in a microfluidic device. By partially blocking the back focal plane of the objective lens, the schlieren microscope produces an image with patterns that correspond to spatial derivative of refractive index in the specimen. Since salinity variation leads to change in refractive index, the fluid mixing of an aqueous salt solution of a known concentration and water in a T-microchannel is used to establish the relation between salinity gradients and grayscale readouts. This relation is then employed to map the salinity gradients in the target microfluidic device from the grayscale readouts of the corresponding micro-schlieren image. For saline solution with salinity close to that of the seawater, the grayscale readouts vary linearly with the salinity gradient, and the regression line is independent of the flow condition and the salinity of the injected solution. It is shown that the schlieren technique is well suited to quantify the salinity gradients in microfluidic devices, for it provides a spatially resolved, non-invasive, full-field measurement.
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spelling pubmed-44820102015-06-29 Mapping the Salinity Gradient in a Microfluidic Device with Schlieren Imaging Sun, Chen-li Chen, Shao-Tuan Hsiao, Po-Jen Sensors (Basel) Article This work presents the use of the schlieren imaging to quantify the salinity gradients in a microfluidic device. By partially blocking the back focal plane of the objective lens, the schlieren microscope produces an image with patterns that correspond to spatial derivative of refractive index in the specimen. Since salinity variation leads to change in refractive index, the fluid mixing of an aqueous salt solution of a known concentration and water in a T-microchannel is used to establish the relation between salinity gradients and grayscale readouts. This relation is then employed to map the salinity gradients in the target microfluidic device from the grayscale readouts of the corresponding micro-schlieren image. For saline solution with salinity close to that of the seawater, the grayscale readouts vary linearly with the salinity gradient, and the regression line is independent of the flow condition and the salinity of the injected solution. It is shown that the schlieren technique is well suited to quantify the salinity gradients in microfluidic devices, for it provides a spatially resolved, non-invasive, full-field measurement. MDPI 2015-05-20 /pmc/articles/PMC4482010/ /pubmed/26007720 http://dx.doi.org/10.3390/s150511587 Text en © 2015 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Sun, Chen-li
Chen, Shao-Tuan
Hsiao, Po-Jen
Mapping the Salinity Gradient in a Microfluidic Device with Schlieren Imaging
title Mapping the Salinity Gradient in a Microfluidic Device with Schlieren Imaging
title_full Mapping the Salinity Gradient in a Microfluidic Device with Schlieren Imaging
title_fullStr Mapping the Salinity Gradient in a Microfluidic Device with Schlieren Imaging
title_full_unstemmed Mapping the Salinity Gradient in a Microfluidic Device with Schlieren Imaging
title_short Mapping the Salinity Gradient in a Microfluidic Device with Schlieren Imaging
title_sort mapping the salinity gradient in a microfluidic device with schlieren imaging
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4482010/
https://www.ncbi.nlm.nih.gov/pubmed/26007720
http://dx.doi.org/10.3390/s150511587
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