José Losada

Two types of hyperbranched ferrocene‐containing polycarbosilanes were obtained by hydrosilylation of polydiallylmethylsilane (hb‐PDAMS) and polymethyldiundecenylsilane (hb‐PMDUS) with diferrocenylmethylsilane. The redox properties of both polymers have been investigated both in solution and confined onto platinum electrodes. The electrocatalytic activity of polymer‐modified electrodes toward the reduction of oxygen as well as the electrochemical reduction and oxidation of hydrogen peroxide has been examined.

An iron(III) doped zeolite modified glassy carbon electrode was constructed for the determination of pyridine-2-aldoxime methochloride. X-ray diffraction and chemical analysis were utilized to determine the optimum pH and chemical content for doping zeolite. Cyclic voltammetry was used to characterize the modified electrode and study the kinetics of the acid treated and untreated modified electrode. Acid treatment of the modified electrode showed a better electrochemical behavior compared to the untreated iron(III) doped zeolite modified electrode. Square wave anodic stripping voltammetry was employed to investigate the working pH and preconcentration time. The analytical performance of the modified electrode was evaluated, and a linear anodic stripping response for pyridine-2-aldoxime methochloride in the concentration range of 0.5–100.0 μM with a detection limit of 1.61 × 10⁻⁷ M was obtained. Finally, the developed method was successfully applied for the determination of pyridine-2-aldoxime methochloride in a biological sample.

In this work, the bioelectrocatalytical properties and kinetic characteristics of new oxidase amperometric biosensors based on two different ferrocene functionalized carbosilane polymers, polydiallylmethylsilane (PDAMS) and polymethyldiundecenylsilane (PMDUS) are described. In the development of these biodevices, glucose oxidase has been used as example of oxidase enzyme, and two different immobilization procedures have been studied. The polymer-modified electrodes act as efficient transducers for glucose sensing in anodic and cathodic aerobic conditions and also in anodic anaerobic conditions, and this fact turns them into useful devices for a wide field of applications. PMDUS has shown to be the bioelectrocatalyst with best kinetic and analytical properties in aerobic media while PDAMS was better in anaerobic conditions. The best aerobic biosensor developed displayed a strictly linear range from 0 to 3.0 mM, a detection limit of 7.8 μM and a response time less than 2 s in an ascorbate interference free work potential interval. The apparent Michaelis–Menten constant was calculated to be 1.36 mM according to the Lineweaver–Burk equation.

The bioelectrocatalytical properties and kinetic characteristics of new oxidase biosensors based on two different carbosilane dendrimers are described. The best glucose biosensor developed displayed, in an ascorbate interference free work potential interval, a strictly linear range from 0 to 4.0 mM, a detection limit of 40,6 μM and a response time less than 3 s. The lactate biosensor displayed a linear range from 0 to 0.8 mM, a detection limit of 0.73 µM and a response time less than 2 s. The apparent Michaelis–Menten constants were calculated to be 4.39 mM and 2.08 mM respectively, according to Lineweaver–Burk equation.

The reaction of bis(ferrocenyl)methylsilane 1 with two carbosilane dendritic cores containing terminal allyl units gives dendrimers functionalized with eight interacting ferrocenyl units. They show two reversible ferrocenyl waves in cyclic voltammetry (CV) and form derivatized Pt electrodes. Platinum electrodes modified with electrodeposited films of these two dendrimers exhibit electrocatalytic activity towards the reduction of oxygen and both oxidation and reduction of hydrogen peroxide. The molecular structure of 1 has been determined by single-crystal X-ray diffraction studies.