Jump to Main Content
Ultratrace Naked-Eye Colorimetric Ratio Assay of Chromium(III) Ion in Aqueous Solution via Stimuli-Responsive Morphological Transformation of Silver Nanoflakes
- Li, Xuemei, Zhang, Shouting, Dang, Yanfeng, Liu, Zheyuan, Zhang, Zhen, Shan, Duoliang, Zhang, Xuehong, Wang, Tiansheng, Lu, Xiaoquan
- Analytical chemistry 2019 v.91 no.6 pp. 4031-4038
- absorbance, aqueous solutions, blood serum, chromium, color, colorimetry, environmental monitoring, humans, nanoparticles, nanosilver, silver, spectroscopy
- In this work, we discover an effective domino-effect-based detection mechanism for the rapid, high-selectivity, and ultrasensitive naked-eye colorimetric ratio assay of chromium(III) ion (Cr³⁺) in aqueous solutions. This naked-eye colorimetric ratio assay to Cr³⁺ relies on changes in absorbance properties that are due to the stimuli response of Cr³⁺ for the morphological transformation of silver nanoflakes. In the presence of Cr³⁺, large silver nanoflakes can be stimulated to transform to small nanoparticles (NPs), which promoted a color change in solution from bright yellow to wine red that was detected by the naked eye and spectroscopic absorption methods. The proposed naked-eye sensing strategy was coupled with an ultraviolet (UV)-spectroscopic chemosensor for the detection of trace Cr³⁺. The detection method showed an ultralow detection limit of 1.4 nM (nanomole) for Cr³⁺ in ultrapure water and 11.5 nM in human serum sample, respectively. On the basis of colorimetry, the lowest concentration of ∼50 nM for Cr³⁺ in ultrapure water and human serum can be detected by the naked eye. This naked-eye-based colorimetric ratio assay for accurate and selective identification and high sensitivity of Cr³⁺ is expected to have large potential and wide applications such as pharmaceutical analysis, clinical diagnosis, and environmental monitoring.