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Prototype microfluidic system for fluorescence-based chemical sensing
Author(s)
Kittidachachan, Pattareeya
Rujihan, Suparat
Damrongsak, Badin
Date Issued
January 1, 2014
Type
Article
Abstract
A prototype microfluidic system for fluorescence detection is presented in this paper. The system consists of an excitation light source, a polymer-based microfluidic channel and an optical detector. Experiments are conducted to demonstrate use of the developed system for fluorescence detection in chemical applications. Three fluorescent dyes - Rhodamine 6G, Coumarin 153 and DCM - with different concentrations ranging from 100 nM to 5 mM are used as the analyte in the experiments. Relationship between the photo-response of the microfluidic system and concentration of fluorescent dyes is investigated. The results are compared to that obtained from a bulk system where the analyte under test is dispensed into a standard-size cuvette. In the bulk system, we found a decrease in the fluorescence signal when dye concentration is higher than 10-5 M for Rhodamine 6G and 10-4 M for Coumarin 153 and DCM. This is probably due to the re-absorption and self-quenching phenomena, which result in low quantum yield of fluorescent dyes at high concentration. However, this problem is not found in microfluidic systems with a low detection volume. In addition, the relationship between the photo-response of the system corresponding to different dye concentrations was modeled based on Beer Lambert's law. The measured results agreed will with the theoretical model.
Citation
Chiang Mai University Journal of Natural Sciences, 13(2), 625-633, 2014