Mercury isles in titanate nanotubes: a new strategy for using mercury electrodes in analytical application

A novel coumarin-benzopyrylium based near-infrared fluorescent probe for Hg2+ and its practical applications

A novel colorimetric and ratiometric NIR fluorescent probe for Hg²⁺ was designed and synthesized based on a coumarin-benzopyrylium platform. The ring-open form of the probe exhibits NIR absorption (670 nm) and emission (720 nm). The probe shows high sensitivity, high selectivity and rapid response (30 s) to Hg²⁺. The detection limit was as low as 6.94 nM. The probe shows high stability in a wide pH range from 2 to 10. Moreover, the probe can be employed for detecting Hg²⁺ in food and biological samples.

Bismuth Film-Coated Gold Ultramicroelectrode Array for Simultaneous Quantification of Pb(II) and Cd(II) by Square Wave Anodic Stripping Voltammetry

The widespread presence of heavy metals in drinking water sources arises as a major health concern, particularly in developing countries. The development of low-cost and reliable detection techniques is identified as a societal need to provide affordable water quality control. Herein, a bismuth film-coated gold ultramicroelectrode array (BF-UMEA) was used for the detection of Pb(II) and Cd(II) in water samples via square wave anodic stripping voltammetry (SWASV). Experimental parameters such as deposition time, Bi(III) concentration, acetate buffer concentration, pH, square wave frequency, amplitude, and step potential were all varied to determine their effects on the current peak intensities of the target metal ions. Ten-fold excess in the concentration of interferences was found to cause a decrease in the stripping peak areas of Cd(II) and Pb(II) in the following order of magnitude: benzene < NaCl < Ni(II) < Cu(II). Using Box-Behnken design, the optimum SWASV parameters that provided maximum current peak areas were 14.76 Hz (frequency), 50.10 mV (amplitude), and 8.76 mV (step potential). The limits of detection of the as-prepared BF-UMEA were 5 and 7 µg L^-1 for Pb(II) and Cd(II), respectively. These results demonstrate the potential use of a BF-UMEA in SWASV for the trace quantification of Pb(II) and Cd(II) in water samples.