Fluorescent Paper Based on CQDs/Rhodamine B: A Ratio and Sensitive Detection Platform for On-Site Fe 3+ Sensing

• Published in: Molecules (Basel, Switzerland) Vol. 29; no. 7
• Main Authors: Han, Guangda, Cai, Jihai, Yang, Lu, Li, Xiaoyun, Wang, Xiaoying
• Format: Journal Article
• Language: English
• Published: Switzerland 07.04.2024
• Subjects: smartphone; carbon quantum dots; xylan; ratio fluorescence paper; Fe3+ sensing
• ISSN: 1420-3049

Fluorescent sensors with single reading are generally subject to unpredictable disturbs from environmental and artificial factors. In order to overcome this barrier of detection reliability, a paper-based optical sensor with proportional fluorescence was established and further combined with a smartphone for visual, on-site and quantitative detection of Fe , which affects the color, smell and taste of water, and endangers the health of plants and animals. The ratio fluorescent probe was fabricated by rhodamine B and carbon quantum dots derived from xylan. The red fluorescence of rhodamine B was inert to Fe , which was referred to as background. And blue emitting carbon quantum dots functioned as signal report units, which would be quenched by Fe and make the fluorescence of the ratio probe change from purple to red. The quantitative detection of Fe was conducted by investigating the RGB value of fluorescent images with a smartphone. With the increase of Fe concentration, the R/B (red/blue) value of the fluorescent paper gradually increased. The linear detection range was 10-180 μM, and the limit of detection was 198.2 nM. The application of ratio fluorescent paper with a smartphone provides a facile method for the rapid detection of ions.