Nickel foam decorated with ZnO nanocrystals using mesoporous silica templates for ultrasensitive electrogenerated chemiluminescence determination of diazinon

Single-step microwave synthesis of a novel ternary nanocomposite as an efficient luminophore and boron nitride quantum dots as a new coreactant for a cathodic ECL monitoring of chlorpyrifos

In this study, a novel and innovative enzyme-free electrochemiluminescence (ECL) pesticide probe based on a ternary nanocomposite, CuS/CQDs/g-C₃N₄NS, was demonstrated for the accurate monitoring of chlorpyrifos. Boron nitride quantum dots were introduced as a new and effective coreactant in comparison with other coreactants, such as hydrogen peroxide, peroxydisulfate, and tripropylamine, in the negative potential range for the first time. The nanocomposite as a promoted luminophore was synthesized by a one-pot microwave route. Carbon quantum dots and copper sulfide nanostructures were truly incorporated on the porous graphitized carbon nitride, which displayed a good cooperative effect on the signal improvement. CuS as a co-reaction accelerator and CQDs with a superior luminescence effect produced more radical species, and thus, the ECL signal was amplified. Upon increasing the appropriate concentration of this coreactant in electrolyte media, the signal intensity of the nanocomposite increases. A low detection limit of 3.0 × 10^-16 M and a wide range from 2.0 × 10^-15 to 7.0 × 10^-9 M were gained. Also, the fabricated pesticide sensor presented excellent repeatability for 20 consecutive optical signals, with a RSD of about 1.4%. Owing to its high proficiency, the developed sensor was applied as a new probe for chlorpyrifos analysis in water and fruit samples.

An enzyme-free electrochemiluminescence insulin probe based on the regular attachment of ZnO nanoparticles on a 3-D nickel foam and H2O2 as an efficient co-reactant

In this study, a highly sensitive, fast, and enzyme-free electrochemiluminescence (ECL) probe based on the decoration of zinc oxide nanoparticles on nickel foam is proposed for insulin determination. A silica film was employed as a size adjusting agent for the modification of the nickel foam surface with ZnO nanoparticles (ZnO NPs). The ECL of the ZnO NP/Ni foam was investigated in a natural medium in the presence of hydrogen peroxide (H₂O₂) as an efficient co-reactant. With increasing insulin concentration, a remarkable improvement in ECL signal was observed, which proved the enhancing effect of insulin on the ECL emission. The characterization of the ZnO-NP/Ni-foam electrode was performed via electrochemical impedance spectroscopy, Brunauer-Emmett-Teller (BET) surface area measurement, X-ray diffraction, field emission scanning electron microscopy (FESEM), and energy-dispersive X-ray analysis techniques. The fabricated electrode was applied for the trace analysis of insulin using the ultrasensitive ECL method in a phosphate buffer solution. Under the optimal conditions, the results showed excellent performance during insulin determination with a wide linear range of 3.57 × 10^-15 M to 2.94 × 10^-9 M, a low detection limit of 1.00 × 10^-16 M, and a relative standard deviation of 1.03%. The proposed ECL sensor with excellent reproducibility, long-term stability, and high selectivity was used for insulin determination in real serum samples with acceptable outcomes.