Theoretical and electrochemical analysis of L-serine modified graphite paste electrode for dopamine sensing applications in real samples

In this study, the carbon paste electrode (CPE) was modified by grinding L-serine in a pestle and mortar. L-serine (L-s) was shown to be an effective electrocatalyst at the modified CPE (MCPE) interface for detecting dopamine (DA). L-sMCPE showed excellent activity to detect DA in commercial injection samples with a recovery range of 98.9 to 100.5 %. Theoretical studies were used to understand the electrocatalysis of L-serine at the atomic level using frontier molecular orbitals (FMO) and analytical Fukui assay. According to theoretical findings, the amine group of L-serine works as an extra oxidation site (reason for enhanced reduction peak DA) and the carboxylic acid group acts as an additional reduction site (reason for enhanced oxidation peak DA) at the L-sMCPE interface

Effective Attenuation of Electromagnetic Waves by Synergetic Effect of α-Fe2O3 and MWCNT/Graphene in LDPE-Based Composites for EMI Applications

In this study, a polymer nanocomposite is synthesized using magnetic and conducting fillers for enhanced electromagnetic interference (EMI) shielding. Alfa-ferrite (α-Fe2O3) nanoparticles with minimal multiwalled carbon nanotube (MWCNT) as low as 5 weight % in combination with variable concentrations of graphene nanoplatelets (GNP) are used as fillers in low-density polyethylene (LDPE) polymer matrix. Nanofillers and the polymer matrix are characterized by various techniques such as XRD, SEM, color mapping, EDAX, TGA, etc. The EMI shielding efficiency of the LDPE-based nanocomposites is tested using Vector Network Analyzer (VNA). The results showed that composite with LDPE:MWCNT:GNP:α-FO-50:5:40:5 displayed enhanced EMI shielding (in X-band (8.2–12.4 GHz) compared to other concentrations studied. This is due to the superior ohmic, dielectric, and magnetic losses at this particular composition and to the synergism amongst the filler. An attenuation of 99.99% was achieved for 5% α-Fe2O3. The mechanistic aspects of the shielding are discussed using permittivity, conductivity, and attenuation