Colorimetric determination of Hg

For the selective analysis of [Hg.sup.2+] in aqueous solution, a receptive sensor has been developed based on magnetic nanocomposite ([Fe.sub.3][O.sub.4]@ZIF-67). This sensor has promising intrinsic peroxidase mimicking activities which oxidize the 3, 3', 5, 5'- tetramethyl benzidine (TMB) in the presence of hydrogen peroxide ([H.sub.2][O.sub.2]). However, the oxidation of TMB was reduced in the presence of antiradical biomolecules Glutathione (GSH) because of its strong cation restoration property. When [Hg.sup.2+] is added, the solution turns into blue colour. The absorbance intensity was proportional to the concentration of [Hg.sup.2+] (0-30 nM) and detection limit was 0.37 nM. This promising property of the nanocomposite will have a wide platform for the colorimetric detection of [Hg.sup.2+]. This sensor could be applied to detect [Hg.sup.2+] in real-time analysis of various samples with reasonable results. Fascinatingly, this colorimetric sensing platform has the great prospective in the application of mercury contamination in industrial sewage. This work is in progress to apply this novel technology for the quantification of [Hg.sup.2+] in clinical samples.