Synthesis of palladium nanoparticles on organically modified silica: Application to design of a solid-state electrochemiluminescence sensor for highly sensitive determination of imipramine

Electroanalysis of Tricyclic Psychotropic Drugs using Modified Electrodes

Background:

Tricyclic psychotropic drugs are defined as a tricyclic rings of the dibenzazepine group with the presence of sulfur and nitrogen atoms. They have been prescribed for antidepressive therapy over the years. Due to their medical importance, many analytical methods have been developed for their monitoring. However, benefits of electrochemical techniques such as costeffectiveness, fast, easy operation and non-destructiveness make them appropriate analytical methods for drug assays. Electrochemical determinations of pharmaceuticals require suitable working electrodes. During years, many electrodes are modified by a variety of modifiers and several sensors were developed based on them. In this regard, nanomaterials, due to their remarkable properties, are one of the most important choices.

Objective:

Here, the application of electroanalytical methods in the determination of electroactive tricyclic psychotropic drugs will be reviewed and the nanomaterials which are used for improvements of the working electrodes will be considered.

3D Nanostructured Palladium-Functionalized Graphene-Aerogel-Supported Fe3O4 for Enhanced Ru(bpy)32+-Based Electrochemiluminescent Immunosensing of Prostate Specific Antigen

We developed a novel Ru(bpy)₃²⁺-based electrochemiluminescence (ECL) immunosensor utilizing palladium nanoparticle (Pd NP)-functionalized graphene-aerogel-supported Fe₃O₄ (FGA-Pd) for real-sample analysis of prostate specific antigen (PSA). 3D nanostructured FGA-Pd, as a novel ECL carrier, was prepared by in situ reduction. Large amounts of Ru(bpy)₃²⁺ could combine with FGA-Pd via electrostatic interaction to establish a brand-new ECL emitter (Ru@FGA-Pd) for improving ECL efficiency. The obtained Ru@FGA-Pd composite was utilized to label the secondary antibody, which generated strong ECL signals with tripropylamine (TPrA) as a coreactant. Furthermore, we demonstrated that the participation of Pd NPs endowed FGA with favorable electrocatalytic ability in the luminescence process to produce more excited state [Ru(bpy)₃²⁺]* for realizing desirable signal amplification. In addition, the primary antibody was captured by gold nanoparticle (Au NP)-functionalized Fe₂O₃ nanodendrites (Au-FONDs), which possessed good electrical conductivity and favorable biocompatibility. Under optimum conditions, the fabricated sandwich-type ECL immunosensor showed a sensitive response to PSA with a low detection limit of 0.056 pg/mL (S/N = 3) and a calibration range of 0.0001-50 ng/mL. Featuring favorable selectivity, stability, and repeatability, the proposed immunosensor is expected to blaze a novel trail for the real sample detection of PSA and other biomarkers.

Kinetic studies of nucleation and growth of palladium nanoparticles

In this paper, the kinetic studies of nucleation and growth processes of palladium nanoparticles formation are presented. As a palladium precursor the chloride complex of Pd(II) and as a reductant l-ascorbic acid, were used. Kinetic studies were conducted under different experimental conditions such as initial concentration of metal ions, ascorbic acid, chloride ions as well as at different temperature and ionic strength. Using Finke-Watzky model kinetic rate constants were established and discussed. The value of activation enthalpy and entropy have also been determined using Eyring-Polanyi equation. For all obtained colloids, plasmons and values of hydrodynamic radius were registered.