Mercury-ion optical sensors

The toxicity of mercury (Hg) to humans, including damage to the nervous system, is well known. Hg cannot be degraded into nontoxic compounds or other elements. It is released mainly through mining, industries, and fossil fuel combustion. Anthropogenic and natural activities, such as volcanoes, transform elemental Hg (Hg-0) into its ionic form [Hg(II)], which bioaccumulates in biota and is biomagnified in the food chain, notably in aquatic environments. This critical report aims to control Hg(II)-ion toxicity through risk assessment, recognition, and removal via high-level waste management. We first discuss successful and up-to-date developments in different techniques, designs and studies that are potentially useful in enhancing the effectiveness of control of Hg(II)-ion toxicity. The key to designing optical nanosensors is to construct chromophore and fluorophore receptors as nanoscale platform scavengers with different functional characteristics (e.g., density, accessibility, and intrinsic mobility), which allow for easy, reliable signaling in continuous monitoring modes. We highlight a technique that depends on the use of engineered mesocage materials that have multidirectional cavities and microsized, particle-like monoliths to control the adsorption/detection of toxic metal ions, especially Hg(II) ions. With regard to proximal sensing, we consider controlled assessment processes that involve the evaluation of intrinsic properties (e.g., signal change, long-term stability, adsorption efficiency, extraordinary sensitivity, selectivity, and reusability). This study provides evidence that miniaturized mesosensor strips can revolutionize consumer and industrial markets with the introduction of ion-sensor strips. (c) 2012 Elsevier Ltd. All rights reserved.