A New Nanocomposite Electrode of Carbon Quantum Dots Doped Functionalized Multi-walled Carbon Nanotubes for Lethal Mercury Sensing

Novel Amperometric Mercury-Selective Sensor Based on Organic Chelator Ionophore

A novel amperometric sensor for the direct determination of toxic mercury ions, Hg²⁺, based on the organic chelator ionophore N, N di (2-hydroxy-5-[(4-nitrophenyl)diazenyl]benzaldehyde) benzene-1,2-diamine (NDBD), and multiwalled carbon nanotubes (MWCNT) immobilized on a glassy carbon electrode surface was developed. The parameters influencing sensor performance including the ionophore concentration, the applied potential, and electrolyte pH were optimized. The sensor response to Hg²⁺ was linear between 1-25 µM with a limit of detection of 60 nM. Interferences from other heavy metal ions were evaluated and the sensor showed excellent selectivity towards Hg²⁺. The method was successfully applied to the determination of mercury ions in milk and water samples.

A smartphone-integrated dual-mode nanosensor based on Fe3O4@Au for rapid and highly selective detection of glutathione

A simple, rapid and straightforward method for detecting reduced glutathione (GSH) was developed supported on smartphone analysis software package and a peroxide simulated catalyst nanoparticles (Fe₃O₄@Au) system. The nanocomposite was prepared by self-assembling technique, and the characterization was carried out using transmission electron microscopy, Fourier transforms infrared, and X-ray diffractometer. Fe₃O₄@Au materials have catalyzed the oxidation of a typical colorimetric substrate in the presence of H₂O₂, with the color changes from colorless to green oxidized. A smartphone with a free self-developed app referred to as "Color Capture" was accustomed live the RGB (red-greenblue) values of color intensity within the Fe₃O₄@Au system and computationally convert them GSH concentrations. The smartphone detection system showed high property and sensitivity of GSH detection. It gave a constant correlation (R² = 0.9973) between the colour intensity of I and the GSH concentration, with a linear vary of 0-0.25 mmol/L, and a detection limit of 0.013 μmol/L. The results obtained were most consistent with the results obtained in ultraviolet spectrophotometry. The colorimetric system is based on smartphone analysis software developed to detect GSH in actual samples with potential application values.

Carbon dot composites for bioapplications: a review

Recent advancements in the synthesis of carbon dot composites and their applications in biomedical fields (bioimaging, drug delivery and biosensing) have been carefully summarized. The current challenges and future trends of CD composites in this field have also been discussed.

Recovered fluorescence of the Cd-nanocluster-Hg(II) system based on experimental results and computational methods

Human Serum Albumin, a plasma protein existing in abundance, was selected as a template and reducing agent for the formation of CdNCs due to two factors: its stability and low cost. In the presence of human serum albumin (HSA), a selective and sensitive, low-cost, environmental friendly, and label-free off-on fluorescent sensor was synthesized and characterized for a bioaccumulating and toxic heavy metal, Hg²⁺ and biothiols. HSA - CdNCs can specifically recognize Hg²⁺ through aggregating NCs and causing fluorescence quenching. Subsequently, with increase in the concentration of biothiols, Hg²⁺ was eliminated from the surface of NC, while the fluorescence was restored. The calculated limits of detection (LOD) were 55 pM for Hg(II) and 14 nM for GSH, respectively. The assay was capable of detecting Hg²⁺ ions and GHS at different concentrations in the range of 0.008 to 8530 nM and 7.5-5157 nM, respectively. Furthermore, the appropriate molecular mechanics (MM) as well as quantum mechanical (QM) methods were performed to optimize and the theoretical investigation of the discussed HSA-profile structures and its interactions with the Cd-NCs (one atom of Cd), Hg²⁺ and glutathione (G).

A new CQDs/f-MWCNTs/GO nanocomposite electrode for arsenic (10−12M) quantification in bore-well water and industrial effluents

Strategic combination ofCQDs/f-MWCNTs/GO/GCE for pico-molar arsenic sensing.