Details

Autor(en) / Beteiligte

• Lopez-Ruiz, Nuria
• Curto, Vincenzo F
• Erenas, Miguel M
• Benito-Lopez, Fernando
• Diamond, Dermot
• Palma, Alberto J
• Capitan-Vallvey, Luis F

Titel

Smartphone-Based Simultaneous pH and Nitrite Colorimetric Determination for Paper Microfluidic Devices

Ist Teil von

• Analytical chemistry (Washington), 2014-10, Vol.86 (19), p.9554-9562

Ort / Verlag

United States: American Chemical Society

Erscheinungsjahr

2014

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• In this work, an Android application for measurement of nitrite concentration and pH determination in combination with a low-cost paper-based microfluidic device is presented. The application uses seven sensing areas, containing the corresponding immobilized reagents, to produce selective color changes when a sample solution is placed in the sampling area. Under controlled conditions of light, using the flash of the smartphone as a light source, the image captured with the built-in camera is processed using a customized algorithm for multidetection of the colored sensing areas. The developed image-processing allows reducing the influence of the light source and the positioning of the microfluidic device in the picture. Then, the H (hue) and S (saturation) coordinates of the HSV color space are extracted and related to pH and nitrite concentration, respectively. A complete characterization of the sensing elements has been carried out as well as a full description of the image analysis for detection. The results show good use of a mobile phone as an analytical instrument. For the pH, the resolution obtained is 0.04 units of pH, 0.09 of accuracy, and a mean squared error of 0.167. With regard to nitrite, 0.51% at 4.0 mg L–1 of resolution and 0.52 mg L–1 as the limit of detection was achieved.