Ultra-sensitive electrochemical detection of levofloxacin using a binder-free copper and graphene composite.

Given the levels of pollution in the aquatic environment and the development of antimicrobial resistance, it is essential to develop sensors, with sensitivity, selectivity, stability, and cost-effectiveness, for the determination of antibiotics. The present article highlights the fabrication of an ultra-sensitive graphene and copper sensor, Gr/Cu, supported on glassy carbon (GCE/Gr/Cu) for the electroanalysis of levofloxacin through a cost-effective electrodeposition method. The sequential electrodeposition of graphene and Cu was optimised to give GCE/Gr/Cu, with the Cu particles well dispersed on the graphene sheets. The composite exhibited very good conducting properties as evidenced from electrochemical impedance studies. Using cyclic voltammetry, an impressive sensitivity of 19.7 µA µM-1 cm-2 was achieved with a detection limit of 11.86 nM, providing a promising electrocatalytic material for the determination of this antibiotic. Moreover, good selectivity was observed in the presence of various ions typically found in water and other drug molecules, while very good stability exceeding a 21-day period was achieved, and recovery values between 97.7 and 103.8 % were obtained in tap water.

Preparation of starch-based porous carbon electrode and biopolymer electrolyte for all solid-state electric double layer capacitor.

An ever-increasing demand for energy coupled with environmental pollution associated with conventional energy production continues to drive the search for alternative renewable energy storage solutions. In this regard, a high surface area (1841 m2 g-1), hierarchically porous (∼1.18 cm3 g-1) and self-inherited nitrogen (2.1 at.wt%) based activated carbon are obtained from Artocarpus heterophyllus seed derived starch as a result of ZnCl2 chemical activation. A flexible, conductive, thermally stable and bio-degradable biopolymer electrolyte film is prepared from Manihot esculenta starch powder. These eco-friendly hierarchically porous architectured carbon electrode and flexible biopolymer electrolytes are employed as significant components in a coin cell-based all-solid-state supercapacitor. The resulting device delivers a high specific capacitance of 240 Fg-1 at 0.5 mA with 97% coulombic efficiency over 2000 cycles. In addition, the device provided excellent specific energy (17 Wh kg-1) and specific power (3823 W kg-1). Interestingly, the starch derived biopolymer electrolyte film, when buried under soil, shows a favourable natural rate of degradation. Therefore, this fabricated electric double layer capacitor can be used as a promising device with little to no potential environmental harm.