Selective Aggregation of Silver Nanoprisms Induced by Monohydrogen Phosphate and its Application for Colorimetric Detection of Chromium (III) Ions

In this study, we established a simple colorimetric method for visual detection of chromium (III) ions using aggregated silver nanoprisms induced by monohydrogen phosphate. The detection strategy had two steps, selective aggregation of silver nanoprisms with monohydrogen phosphate at high temperature, and anti aggregation of silver nanoprisms in the presence of chromium (III) ions. In this strategy, significant spectral shift of the localized surface plasmon resonance (LSPR) absorption peak of silver nanoprisms could be visualized with the color changed from yellow to blue. The spectral peak shift of silver nanoprisms in the anti-aggregation process was linear with the concentrations of the added chromium (III) ions in the range of 20.0–800.0 nM. Thus, a colorimetric method for chromium (III) ions detection was established with the detection limit of 3.6 nM. The experimental results of real water samples indicated that the colorimetric sensor was potential in environmental monitoring.