Quantitative Visual Detection of Mercury Ions With Ratiometric Fluorescent Test Paper Sensor

Abstract

A novel ratiometric fluorescence probe based on nitrogen-doped blue carbon dots (NCDs) and red gold nanoclusters (Au NCs) for mercuric ion (Hg2+) has been prepared and characterized. A user friendly fluorescent test paper based sensor combined with smartphone was fabricated for rapid visual and quantitative detection. Hg2+ can specifically bind to Au+ on the surface of Au NCs, leading to the quench of red fluorescence while the fluorescence intensity of the NCDs with blue fluorescence remained unchanged as a internal standard signal. The implement of paper-based sensor address some common drawback in analytical process such as the detection time, analysis cost. In a further demonstration, a homemade detection device with smartphone was used to qualify the Hg2+. After adding different concentration of Hg2+, red, purple, and blue colors were obtained on the detection zones of the fluorescent test paper. The Android App Color Grab was used to identify the red, green and blue (RGB) values of fluorescent color. The rapid visual and quantitative detection of Hg2+ was accomplished with the detection limit of 2.7 nM for fluorescence, 25 nM for smartphone and 32 nM for paper strip. The developed multi-mode detection platform was successfully applied to the detection of mercury ions in water samples with acceptable recoveries. The NCDs and Au NCs probe facilitate the one-site environmental monitoring for Hg2+ with “naked-eye” and smartphone.

Gold nanocluster composites: preparation strategies, optical and catalytic properties, and applications

“…In addition, the analysis function of the red, green, and blue (RGB) value of smartphones increases the utility of AuNC composites. Fan and co-workers 115 used the Android App Color Grab to identify the RGB values of fluorescent color after adding Hg 2+ to the test paper. The developed detection platform was successfully applied in water samples, proving the convenience and practicality of this method.…”

Recent advances in the visual detection of ions and molecules based on gold and silver nanoclusters

“…Based on this, Fan et al designed and prepared a ratiometric fluorescent nanoprobe based on nitrogen-doped blue CDs (NCDs) and AuNCs for the rapid visual detection of Hg 2+ . 82 A smart phone was used to recognize the red, green and blue (RGB) values of color, as shown in Fig. 6A.…”

Ratiometric fluorescence detection of Hg2+ based on gold nanocluster/carbon quantum dots nanohybrids

“…20,21 Ratiometric fluorescence assay can greatly minimize the influence of the instrument, background, and environmental signals, and improve quantification and accuracy through the measurement of the ratio of two signals. 22,23…”

“…20,21 Ratiometric uorescence assay can greatly minimize the inuence of the instrument, background, and environmental signals, and improve quantication and accuracy through the measurement of the ratio of two signals. 22,23 Metal nanoclusters (MNCs) have gained wide attention and undergone rapid progress in recent years because of their unusual physicochemical properties and excellent biocompatibility, and are widely used in sensing, bioimaging, therapy, catalysis, etc. 24 The related synthesis methods and ligands have an impact on the particle size, morphology, and crystalline structure of the MNCs.…”