Analytical Sciences

Microfluidic Paper-based Analytical Device for the Determination of Hexavalent Chromium by Photolithographic Fabrication Using a Photomask Printed with 3D Printer

Hitoshi ASANO* and Yukihide SHIRAISHI**

*Center for Liberal Arts and Sciences, Tokyo University of Science, Yamaguchi, 1-1-1 Daigaku-Dori, Sanyo Onoda, Yamaguchi 756-0884, Japan
**Department of Applied Chemistry, Faculty of Engineering, Tokyo University of Science, Yamaguchi, 1-1-1 Daigaku-Dori, Sanyo Onoda, Yamaguchi 756-0884, Japan

This article describes a simple and inexpensive microfluidic paper-based analytical device (μPAD) for the determination of hexavalent chromium (Cr^VI) in water samples. The μPADs were fabricated on paper by photolithography using a photomask printed with a 3D printer and functionalized with reagents for a colorimetric assay. In the μPAD, Cr^VI reacts with 1,5-diphenylcarbazide to form a violet-colored complex. Images of μPADs were captured with a digital camera; then the red, green, and blue color intensity of each detection zone were measured using images processing software. The green intensity analysis was the best sensitive among the RGB color. A linear working range (40 – 400 ppm; R² = 0.981) between the Cr^VI and green intensity was obtained with a detection limit of 30 ppm. All of the recoveries were between 94 and 109% in recovery studies on water samples, and good results were obtained.

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