Pencil graphite is electrochemically exfoliated to obtain few layered graphene oxide (GO) in hydrochloric acid (HCl, HGO), sodium hydroxide (NaOH, NGO) and phosphate buffer saline (PBS, pH 7.4, PGO) media at a constant potential (+7.0 V) without ionic 10 liquid for the first time. Thus, obtained graphene oxide is deposited (by drop casting and electro reduction) onto a glassy carbon electrode (GCE). Following this, gold nanoparticles (AuNP) are electro deposited to form GO-AuNP composite for simultaneous discrimination of dopamine (DA), ascorbic acid (AA) and uric acid (UA) at pH 7.4. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques reveal well separated oxidation peaks for DA, AA and UA. The sensor surfaces are characterized by Ultraviolet Visible (UV-Vis), Photoluminescence (PL), X-ray diffraction (XRD), Fourier transform Infrared (FTIR), contact angle goniometry (CA) and scanning 15 electron microscopy (SEM) techniques. DA, AA and UA are studied individually to evaluate the dynamic ranges and lowest detection limits of the sensor by the DPV method. Concentrations of DA, AA and UA in real samples viz., dopamine injection, vitamin C tablets and human urine samples are evaluated.

No abstract

No abstract

No abstract

A novel Gd 2 O 3 nanosheet was synthesized by the template-free chemical coprecipitation method. Interestingly, upon calcination at 600 °C, nanoparticles were transformed into a nanosheet, as observed from field emission scanning electron microscopy (FESEM) images. An increase in the calcination temperature to 600 °C increases the particle size to 50 nm, which results in aggregation. A sheetlike Gd 2 O 3 exhibits superparamagnetism from 300 K. The highly selective nonenzymatic sensing of riboflavin (RF) was studied using a modified glassy carbon electrode with Gd 2 O 3 nanosheets, and its various applications were made possible by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The redox behavior of the RF was determined. The newly fabricated sensor showed high sensitivity, stability, and reproducibility and was also tested with a commercial vitamin B2 tablet and a milk powder sample.

No abstract

No abstract

No abstract