en
Scientific article
Open access
English

Quantification of Colorimetric Data for Paper-Based Analytical Devices

Published inACS Sensors, vol. 4, no. 12, p. 3093-3101
Publication date2019
Abstract

Colorimetric measurements by image analysis, giving RGB or HSV data, have become commonplace with optical indicator-based assays and as a readout for paper-based analytical devices (PADs). Yet, most works on PADs tend to ignore the quantitative relationship between color data and concentration, which may hamper their establishment as analytical devices and make it difficult to properly understand chemical or biological reactions on the paper substrate. This Perspective Article discusses how image color data are computed into colorimetric absorbance values that correlate linearly to dye concentration and compare well to traditional spectrophotometry. Thioflavin T (ThT), Neutral Red (NR), and Orange IV are used here as model systems. Absorbance measurements in solution correlate well to image data (and Beer's law) from the color channel of relevance if the gamma correction normally used to render the picture more natural to the human eye is removed. This approach also allows one to correct for color cast and variable background color, which may otherwise limit quantitation in field measurements. Reflectance measurements on paper color spots are equally found to correlate quantitatively between spectroscopy and imaging devices. In this way, deviations from Beer's law are identified that are explained with dye interactions on the paper substrate.

Keywords
  • Colorimetry
  • RGB analysis
  • Scanner
  • Gamma correction
  • Background light correction
  • Smartphone analysis
  • Paper-based analytical devices
Citation (ISO format)
SODA, Yoshiki, BAKKER, Eric. Quantification of Colorimetric Data for Paper-Based Analytical Devices. In: ACS Sensors, 2019, vol. 4, n° 12, p. 3093–3101. doi: 10.1021/acssensors.9b01802
Main files (1)
Article (Published version)
accessLevelPublic
Identifiers
ISSN of the journal2379-3694
310views
139downloads

Technical informations

Creation09/17/2020 9:32:00 AM
First validation09/17/2020 9:32:00 AM
Update time03/15/2023 10:38:00 PM
Status update03/15/2023 10:37:59 PM
Last indexation01/17/2024 10:55:27 AM
All rights reserved by Archive ouverte UNIGE and the University of GenevaunigeBlack