Analytical Sciences

A Simple Microfluidic Integrated with an Optical Sensor for Micro Flow Injection Colorimetric Determination of Glutathione

Sam-ang SUPHAROEK,* Napaporn YOUNGVISES,** and Jaroon JAKMUNEE*

*Department of Chemistry, and Center of Excellence for Innovation in Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand
**Department of Chemistry, Faculty of Science and Technology, Thammasat University, Pathum Thani 12121, Thailand

A simple and inexpensive method for fabricating a microfluidic platform was developed. A printed circuit board (PCB) was used to make a master mold for replicating a polydimethylsiloxane (PDMS) microchannel. The master mold was fabricated by a simple photolithographic method, employing a photoresist dry film. The process did not use hazardous chemicals, a clean room or any expensive instrument. The PDMS microchannel was clamped with polymethylmethacrylate (PMMA) plates, where a light emitting diode (LED) as a light source and a light dependent resistor (LDR) as a light sensor were attached to form a simple optical sensor. The system was successfully employed as a micro flow injection analysis for the determination of glutathione in dietary supplement samples. A linear calibration graph in the range of 5.0 – 60.0 mg L⁻¹ glutathione was obtained with a detection limit of 0.01 mg L⁻¹. The system provided a sample throughput of 48 h⁻¹, with microliter consumption of the reagent.

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