A new modified working electrode of glassy carbon electrode with nanoparticles of SiO₂ (SiO₂ nanoparticles/GCE) was prepared by mechanical attachment method. The modified electrode (SiO₂ nanoparticles/GCE) was characterised by electrochemical analysis using cyclic voltammetric technique to evaluate this electrode as nano-sensor. A standard solution of 1 mM K₄[Fe(CN)₆] with 1 M KCl as an electrolyte was used to study the redox current peaks of FeⅡ/FeⅢ ions on the modified electrode at different concentrations, scan rates, pH, determination of diffusion coefficient (D_f), reliability and stability of the modified electrode. It was found the new nano-sensor (SiO₂ nanoparticles/GCE) had enhancement for the oxidation and reduction current peak of FeⅡ/FeⅢ ions of about 1.29 and 1.58 μA, respectively. The current ration value of the new modified electrode was I_pa /I_pc = 1.7 with the peak separation of ∆E_pa-c = 140 mV, which demonstrated that the new modified electrode acted in electrolyte as irreversible and heterogeneous reaction, had low detection limit, and enhanced the redox current peaks in acidic pH with good reliability and stability of nanoparticles on the surface of GCE.

For the first time, one of the antibiotic nanoparticles such as a classical form of ampicillin trihydrate compound was studied. The electrochemical behavior of ampicillin nanoparticles was investigated in blood medium using cyclic voltammetric technique by glassy carbon electrode. The results showed that the oxidation-reduction current peaks of ampicillin nanoparticles in blood medium were different from that of microparticles. The nanoparticles acted as anti-oxidative antibiotic by making the oxidation current peak at 1 V disappear, while the oxidation peak of microparticles still appeared in blood medium; hence, ampicillin at microform acted as oxidative reagent in blood medium. A good reliability and stability of glassy carbon electrode in blood medium was found with low values of RSD for oxidation-reduction current peaks at ±0.52% and ±0.038% respectively. Scanning electron microscopy for the characterization of ampicillin trihydrate nanoparticles was studied.

Cyclic voltammetric technique using glassy carbon electrode of cobalt chloride Co(Ⅱ) was studied in blood medium for the effect of ascorbic acid as an electrocatalyst reagent on the oxidation reduction current peaks of Co(Ⅱ). It was found that the two oxidation reduction current peaks for Co(Ⅱ) in 0.1M KCl as electrolyte were at 900 and 250 mV respectively. In the study of Co(Ⅱ) in blood medium the result was different, in that the reduction current peak disappeared and the oxidation current peak shifted to a higher potential at 1.4 V. The other study for the effects of different concentrations of ascorbic acid on the anodic current peak of Co(Ⅱ) in blood medium showed an enhancement of the oxidation current peak about three times and the ascorbic acid acted as an electrocatalyst in blood components which caused damage to blood cells.