Taking advance of isotropic-to-anisotropic morin-modified silver nanoparticles for simultaneous colorimetric sensing of trivalent chromium and iron ions

Taking into account colorimetric sensing purposes of silver nanoparticles (AgNPs), a convenient system for simultaneous detection of multiple metal ions has been more challenging and less exploited. In the present work, at the same condition (involving AgNPs and morin concentrations, pH and incubation time), morin-modified AgNPs were firstly applied to the simultaneous detection of Cr3+ and Fe3+ ions by naked eyes and ultraviolet-visible spectrophotometry. Furthermore, method validation was also carried out involving specification, selectivity, limits of detection and quantification. The colorimetric sensing mechanisms for such metal ions were admitted via an anisotropic growth of AgNPs, resulting in either larger aggregates due to a coordination complex (Cr3+ ion) or a smaller size due to a redox cycle (Fe3+ ion).