A fluorescent probe for zinc ions based on N-methyltetraphenylporphine with high selectivity

A zinc selective oxytocin based biosensor

Oxytocin is a peptide hormone with high affinity to both Zn²⁺ and Cu²⁺ ions compared to other metal ions. This affinity makes oxytocin an attractive recognition layer for monitoring the levels of these essential ions in biofluids. Native oxytocin cannot differentiate between Cu²⁺ and Zn²⁺ ions and hence it is not useful for sensing Zn²⁺ in the presence of Cu²⁺. We elucidated the effect of the terminal amine group of oxytocin on the affinity toward Cu²⁺ using theoretical calculations. We designed a new Zn²⁺ selective oxytocin-based biosensor that utilizes the terminal amine for surface anchoring, also preventing the response to Cu²⁺. The biosensor shows exceptional selectivity and very high sensitivity to Zn²⁺ in impedimetric biosensing. This study shows for the first time an oxytocin derived sensor that can be used directly for sensing Zn²⁺ in the presence of Cu²⁺.

Biologically synthesized silver nanoparticle-based colorimetric sensor for the selective detection of Zn2+

Schematic illustration for the colorimetric detection of Zn²⁺.

Improvement in the performance of a zinc ion-selective potentiometric sensor using modified core/shell Fe3O4@SiO2nanoparticles

A novel, simple, accurate and sensitive zinc ion-selective potentiometric sensor was fabricated by modifying the surface of Fe₃O₄@SiO₂nanoparticles using a ligand prepared by a coupled reaction between APTMS and 2-H-3-MBA.

Recent progress in optical chemical sensors

Optical chemical sensors have promoted escalating interest in the determination of various pollutants in the environment, which are creating toxicity and may cause serious health problems. This review paper focuses particularly on the recent progress and developments in this field; the working principles and basic classes of optical chemical sensors have been briefly described.

Potentiometric zinc ion sensor based on honeycomb-like NiO nanostructures

In this study honeycomb-like NiO nanostructures were grown on nickel foam by a simple hydrothermal growth method. The NiO nanostructures were characterized by field emission electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) techniques. The characterized NiO nanostructures were uniform, dense and polycrystalline in the crystal phase. In addition to this, the NiO nanostructures were used in the development of a zinc ion sensor electrode by functionalization with the highly selective zinc ion ionophore 12-crown-4. The developed zinc ion sensor electrode has shown a good linear potentiometric response for a wide range of zinc ion concentrations, ranging from 0.001 mM to 100 mM, with sensitivity of 36 mV/decade. The detection limit of the present zinc ion sensor was found to be 0.0005 mM and it also displays a fast response time of less than 10 s. The proposed zinc ion sensor electrode has also shown good reproducibility, repeatability, storage stability and selectivity. The zinc ion sensor based on the functionalized NiO nanostructures was also used as indicator electrode in potentiometric titrations and it has demonstrated an acceptable stoichiometric relationship for the determination of zinc ion in unknown samples. The NiO nanostructures-based zinc ion sensor has potential for analysing zinc ion in various industrial, clinical and other real samples.

Fluorescence "turn-on" chemosensor for the selective detection of zinc ion based on Schiff-base derivative

N,N'-phenylenebis(salicylideaminato) (L) has been used to detect trace amounts of zinc ion in acetonitrile-water solution by fluorescence spectroscopy. The fluorescent probe undergoes fluorescent emission intensity enhancement upon binding to zinc ions in MeCN/H(2)O (1:1, v/v) solution. The fluorescence enhancement of L is attributed to the 1:1 complex formation between L and Zn(II), which has been utilized as the basis for selective detection of Zn(II). The linear response range for Zn(II) covers a concentration range of 1.6x10(-7) to 1.0x10(-5)mol/L, and the detection limit is 1.5x10(-7)mol/L. The fluorescent probe exhibits high selectivity over other common metal ions, and the proposed fluorescent sensor was applied to determine zinc in water samples and waste water.