Colorimetric detection of Hg(II) by measurement the color alterations from the “before” and “after” RGB images of etched triangular silver nanoplates
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It is shown that triangular silver nanoplates (TAgNPs) are viable colorimetric probes for the fast, sensitive and selective detection of Hg(II). Detection is accomplished by reducing Hg(II) ions to elemental Hg so that an Ag/Hg amalgam is formed on the surface of the TAgNPs. This leads to the inhibition of the etching TAgNPs by chloride ions. Correspondingly, a distinct color transition can be observed that goes from yellow to brown, purple, and blue. The color alterations extracted from the red, green, and blue part of digital (RGB) images can be applied to the determination of Hg(II). The relationship between the Euclidean distances (EDs), i.e. the square roots of the sums of the squares of the ΔRGB values, vary in the 5 nM to 100 nM Hg(II) concentration range, and the limit of detection is as low as 0.35 nM. The color changes also allow for a visual estimation of the concentrations of Hg(II). The method is simple in that it only requires a digital camera for data acquisition and a Photoshop software for extracting RGB variations and data processing.
KeywordsTriangular silver nanoplates Mercury ions Colorimetric probe RGB images Digital camera Photoshop software Euclidean distance
All authors gratefully acknowledge the financial support of Scientific Research Project of Beijing Educational Committee (Grant No. KM201710028009).
Compliance with ethical standards
The author(s) declare that they have no competing interests.
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