Novel solid-state mercury(II)-selective electrode based on symmetrical sulfur-containing carrier

A novel miniaturized potentiometric electrode based on carbon nanotubes and molecularly imprinted polymer for the determination of lidocaine

A novel miniaturized, solid-contact potentiometric screen-printed electrode was developed for highly sensitive and selective determination of lidocaine anesthetic. The electrode integrated single-walled carbon nanotubes as a solid-contact material and a molecularly imprinted polymer as a recognition sensory material. The performance characteristics of the electrode were evaluated and optimized to display a Nernstian slope of 58.92 ± 0.98 mV/decade over a linear concentration range of 4.53 × 10-7 to 6.18 × 10-3 mol/l within < 6 s. The detection limit was 7.75 × 10-8 mol/l (18.16 ng/ml) of lidocaine. The use of the molecularly imprinted polymer significantly enhanced the selectivity of the electrode, and carbon nanotubes increased the sensitivity, accuracy, and potential stability. The electrode was successfully used for determining lidocaine in pharmaceutical preparations and human urine. The results favorably compared with data obtained by liquid chromatography-tandem mass spectrometry.

Preparation and application of a new ion-imprinted polymer for nanomolar detection of mercury(II) in environmental waters

This study introduces a novel ion-imprinted polymer for the ultrasensitive detection of mercury(II) in water. The ion-imprinted polymer was synthesized via a simple bulk polymerization process using methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the cross-linker, morpholine-4-carbodithioic acid phenyl ester as the chelating agent, and ammonium persulfate as the initiator. The electrochemical mercury(II) sensing capability of the ion-imprinted polymer was studied via the modification of a cost-effective carbon paste electrode. A stripping voltammetric technique was utilized to quantify the analyte ions following open-circuit enrichment. Critical experimental parameters, including the nature and concentration of the eluent, solution pH, preconcentration duration, ion-imprinted polymer dosage, sample solution volume and reduction potential, were systematically studied and optimized. Under optimal conditions, the sensor exhibited a linear response in the range of 1.0 to 240.0 nM, with a low detection limit of 0.2 nM. The sensor demonstrated remarkable selectivity against potential interfering ions, including lead(II), cadmium(II), copper(II), zinc(II), manganese(II), iron(II), magnesium(II), calcium(II), sodium(I) and cobalt(II). The practical applicability of the developed method was successfully validated through the analysis of real water samples, suggesting its potential for environmental monitoring applications.

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.

Stripping voltammetric detection of copper ions using carbon paste electrode modified with aza-crown ether capped gold nanoparticles and reduced graphene oxide

A novel electrochemical sensor based on reduced graphene oxide (RGO) and kryptofix 21-capped gold nanoparticles (GNPs) has been proposed.