| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 5009287 | Sensors and Actuators B: Chemical | 2017 | 8 Pages |
•A new colorimetric sensor based on three color changes of AuNPs was developed for Hg2+ detection.•Detection of Hg2+ through three different color changes could enhance the selectivity of the sensor, minimizing the chance of false detection.•The observed response was linear for the range 8.76 × 10−9 to 1.27 × 10−4 M, indicating this colorimetric sensor was a high potential candidate for Hg2+ detection.•Multiple color changes based colorimetric sensor provides a novel insight for designing Hg2+ sensing probe.
A new colorimetric method of detecting Hg2+ in aqueous solutions was proposed, based on the three color changes of gold nanoparticles (AuNPs) with the assistance of ascorbic acid (AA) and multi-sulfhydryl functionalized hyperbranched polyethylenimine (SH-HPEI). The mechanism of sensing is based on the formation of Au-Hg alloy and its aggregation, along with the corresponding three color changes from red (AuNPs) through sandy beige (Au-Hg alloy) to celandine green (larger Au-Hg alloy). Compared with usual colorimetric assays with only one color change progress from red to blue or red to purple of reported AuNPs, this assay is highly selective for Hg2+ detection due to the fact that the appearing probability of identical three color changes triggered by interfering agents or the possibility of false positive results is very, very low. The detection limit of 8.76 × 10−9 M is lower than the guideline value of Hg2+ (30 nM) in drinking water defined by the World Health Organization (WHO). Meanwhile, the concentration range (from 8.76 × 10−9 to 1.27 × 10−4 M) of this new detection method is the widest one that has been reported. Moreover, this method is successfully applied to detecting Hg2+ in real water sample. More importantly, this novel colorimetric sensor based on multiple color changes may open a new avenue for the development of Hg2+ sensing probes.
Graphical abstractThe novel red through sandy beige to celandine green colorimetric sensor for Hg2+ detection based on multi-sulfhydryl functionalized hyperbranched polyethylenimine stabilized Au-Hg alloys showed high sensitivity and selectivity.Figure optionsDownload full-size imageDownload high-quality image (98 K)Download as PowerPoint slide
