Tannic Acid-Functionalized Silver Nanoparticles as Colorimetric Probe for the Simultaneous and Sensitive Detection of Aluminum(III) and Fluoride Ions

[Image: see text] In this study, we employed tannic acid (TA)-functionalized silver nanoparticles (TA@AgNPs) as colorimetric probe for the simultaneous and sensitive detection of Al(III) and F(–) ions. The proposed sensor was based on the aggregation and anti-aggregation effects of target Al(III) and F(–) ions on TA@AgNPs, respectively. Because of the strong coordination bond between Al(III) ions and TA, the addition of Al(III) ions to TA@AgNPs could cause aggregation and, hence, result in a significant change in the absorption and color of the test solution. Interestingly, in the presence of F(–) ions, the aggregation effect of Al(III) ions on TA@AgNPs can be effectively prevented. The extent of aggregation and anti-aggregation effects was concentration-dependent and can be used for the quantitative detection of Al(III) and F(–) ions. The as-proposed sensor presented the sensitive detection of Al(III) and F ions with limits of detection (LOD) of 0.2 and 0.19 μM, respectively. In addition, the proposed sensor showed excellent applicability for the detection of Al(III) and F(–) ions in real water samples. Moreover, the sensing strategy offered a simple, rapid, and sensitive detection procedure and could be used as a potential alternative to conventional methods, which usually involve sophisticated instruments, complicated processes, and a long detection time.