We use cookies to ensure that we give you the best experience on our website. By continuing to browse this repository, you give consent for essential cookies to be used. You can read more about our Privacy and Cookie Policy.

Durham Research Online
You are in:

Towards a high-throughput real-time confocal microfluidic system for monitoring absorbance spectra in mixed-phase chemical reactions.

Lawton, P. F. and Girkin, J. M. (2017) 'Towards a high-throughput real-time confocal microfluidic system for monitoring absorbance spectra in mixed-phase chemical reactions.', Microfluidics and nanofluidics., 21 (4). p. 69.


In this work, we present a compact, real-time absorbance spectroscopy instrument, designed with a particular focus on taking spectroscopic readings in a microfluidic channel environment and selectively analysing an active volume in this channel by adding confocality. There are time-saving advantages to industry in carrying out and monitoring chemical reactions in a high-throughput microfluidic environment as opposed to manually mixing and then analysing chemicals. In this paper, we use absorbance spectroscopy to investigate a particular complex mixed-phase reaction (specifically, the reaction of colloidal diluted hair dye with an oxidising agent and catalyst), which has an additional complication of oxygen gas being released then trapped in the mixture as the reaction progresses. We find that the results obtained using our instrument are comparable to those obtained in a standard spectrometer. Oxygen bubbles formed in the reaction, however, present a significant obstacle to obtaining the correct sample depth in narrow flow channels. This is mitigated through the use of a camera which views the reaction between the glass and liquid through the use of remote reimaging, allowing the bubbles to be detected via histogram analysis while spectroscopy takes place enabling rogue readings to be removed, and also serves to monitor the overall density of the ‘gassy colloidal’ mixture produced.

Item Type:Article
Full text:(VoR) Version of Record
Available under License - Creative Commons Attribution.
Download PDF
Publisher Web site:
Publisher statement:Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
Date accepted:20 March 2017
Date deposited:30 March 2017
Date of first online publication:28 March 2017
Date first made open access:30 March 2017

Save or Share this output

Look up in GoogleScholar