carbon paste electrode was modified by disodium 2,4-diamino-7-methylbenzo[g] pteridine-5,10-dioxide to fabricate a sensor for potentiometric determination of vanadyl ion (vo2+) in aqueous medium. the new ligand was synthesized in three steps with high yield. the optimal composition of the carbon paste was made of graphite powder (64.5%), ionophore (16.6%), paraffin oil (17.8%), and sodium tetra...

A new method was developed for simultaneous determination of copper, lead, and cadmium, based on their voltammetric response at a carbon paste electrode modified with hexagonal mesoporous silica (HMS) immobilized quercetin (HMS-Qu/CPE). Compared with quercetin modified carbon paste electrode (Qu/CPE) and quercetin ionic liquid modified carbon paste electrode (Qu-IL/CPE), the HMS-Qu/CPE exhibite...

graphene-based nanocomposites are newly emerged materials with a wide range of applications such as in supercapacitors electrode. the high conductivity and ability for passing electric current, makes graphene an appropriate new item to be used in cells. electroactive transition metal oxides, owing fast reversible redox pairs, are used to store electrical charge. furthermore, the graphene/nio na...

Graphene has attracted considerable attention as a next-generation transparent conducting electrode, because of its high electrical conductivity and optical transparency. Various optoelectronic devices comprising graphene as a bottom electrode, such as organic light-emitting diodes (OLEDs), organic photovoltaics, quantum-dot LEDs, and light-emitting electrochemical cells, have recently been rep...

An improved process for graphene transfer was used to demonstrate high performance graphene enabled vertical organic field effect transistors (G-VFETs). The process reduces disorder and eliminates the polymeric residue that typically plagues transferred films. The method also allows for purposely creating pores in the graphene of a controlled areal density. Transconductance observed in G-VFETs ...

A non-invasive brain-machine interface (BMI) or brain-computer interface is a technology for helping individuals with disabilities and utilizes neurophysiological signals from the brain to control external machines or computers without requiring surgery. However, when applying electroencephalography (EEG) methodology, users must place EEG electrodes on the scalp each time, and the development o...

A bi-enzymatic biosensor (LACC-TYR-AuNPs-CS/GPE) for carbamates was prepared in a single step by electrodeposition of a hybrid film onto a graphene doped carbon paste electrode (GPE). Graphene and the gold nanoparticles (AuNPs) were morphologically characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, dynamic light scattering and laser Doppler velocimetry. The ele...

a novel modified ni-zsm-5 nanozeolite was fabricated via an organic template-free hydrothermal route. the average particle size of ni-zsm-5 nanozeolite was calculated to be 85 nm by scanning electronic microscopy. then, carbon paste electrode (cpe) was modified by ni-zsm-5 nanozeolite and ni2+ ions were then incorporated to the nanozeolite matrix. electrochemical behavior of this electrode was ...

In this paper, the effect of cationic and anionic ion sizes on the charge storage capability of graphene nanosheets is investigated. The electrochemical properties of the produced electrode are studied using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques in 3M NaCl, NaOH, and KOH electrolytes. Scanning electron microscopy (SEM) is used to characterize the mi...

a graphene nanosheets (gns) film coated glassy carbon electrode (gce) was fabricated for sensitive determination of tyrosine (tyr). the gns-based sensor was characterized by scanning electron microscope and electrochemical impedance spectroscopy. the voltammetric techniques were employed to study electro-oxidation of tyr. the results revealed that the modified electrode showed an electrocatalyt...