Zero-valent Iron Nanoparticles Modified Screen-printed Electrode for FIA or HPLC Amperometric Detection of Metronidazole in Pharmaceutical Formulations

Materials interacting with inorganic selenium from the perspective of electrochemical sensing

Inorganic selenium, the most common form of harmful selenium in the environment, can be determined using electrochemical sensors, which are compact, fast, reliable and easy-to-operate devices. Despite progress in this area, there is still significant room for developing high-performance selenium electrochemical sensors. To achieve this, one should take into account (i) the electrochemical process that selenium undergoes on the electrode; (ii) the valence state of selenium species in the sample and (iii) modification of the sensor surface by a material with high affinity to selenium. The goal of this review is to provide a knowledge base for these issues. After the Introduction section, mechanisms and principles of the electrochemical reduction of selenium are introduced, followed by a section introducing the modification of electrodes with materials interacting with selenium and a section dedicated to speciation methods, including the reduction of non-detectable Se(VI) to detectable Se(IV). In the following sections, the main types of materials (metallic, polymers, hybrid (nano)materials…) interacting with inorganic selenium (mostly absorbents) are reviewed to show the diversity of properties that may be endowed to sensors if the materials were to be used for the modification of electrodes. These features for the main material categories are outlined in the conclusion section, where it is stated that the engineered polymers may be the most promising modifiers.

Low potential detection of antiprotozoal drug metronidazole with aid of novel dysprosium vanadate incorporated oxidized carbon nanofiber modified disposable screen-printed electrode

In this work, we designed tetragonal nanogravel structured dysprosium vanadate Dy(VO₄) nanoparticles unified with oxidized carbon nanofiber (f-CNF) denoted as Dy(VO₄)/f-CNF nanocomposite for the low potential determination of antiprotozoal drug metronidazole (MEZ). The physicochemical properties of novel Dy(VO₄)/f-CNF nanocomposite were analyzed through microscopic and spectroscopic techniques and obtained results express nanocomposite formed with desired surface morphology, crystalline phase, atomic vibrational modes, and preferred elemental compositions. The electrocatalytic activity of Dy(VO₄)/f-CNF nanocomposite was examined with a disposable screen-printed electrode (SPCE) via cyclic voltammetry (CV) and linear sweep voltammetry technique (LSV) with a conventional three-electrode system. Dy(VO₄)/f-CNF/SPCE delivers a higher active surface area recommends superior electrocatalytic activity which is favorable for the MEZ sensor. Electrocatalytic reduction of MEZ occurred with lower reduction potential (-0.55 V) with dynamic linear range (1.5-1036.9 µM), lower detection limit (6 nm), LOQ (0.022 µM), and higher sensitivity (1.12 μA μM^-1 cm²). The anti-interference studies retain its actual current without any shift in cathodic potential. Besides, the practical feasibility outcomes with higher cathodic current with the higher recovery rate and RSD in human blood sample, urine sample, and lake water as a real samples. Thus, Dy(VO₄)/f-CNF nanocomposite modified SPCE considers being a potential candidate for the MEZ sensor.