ABSTRACT
In this study, we demonstrate the influence of crystallinity and morphology on the analytical performance of various Cu2MoS4 (CMS) nanocatalysts-based electrochemical sensors for the high-efficiency detection of Ofloxacin (OFX) antibiotic. The electrochemical kinetics parameters including peak current response (ΔIp), peak-to-peak separation (ΔEp), electrochemically active surface area (ECSA), electron-transfer resistance (Rct), were obtained through the electrochemical analyses, which indicate the single-crystalline nature of CMS nanomaterials (NMs) is beneficial for enhanced electron-transfer kinetics. The morphological features and the electrochemical results for OFX detection substantiate that by tuning the tube-like to plate-like structures of the CMS NMs, it might noticeably enhance multiple adsorption sites and more intrinsic active catalytic sites due to the diffusion of analytes into the interstitial spaces between CMS nanoplates. As results, highly single-crystalline and plate-shaped morphology structures of CMS NMs would significantly enhance the electrocatalytic OFX oxidation in terms of onset potential (Eonset), Tafel slope, catalytic rate constant (kcat), and adsorption capacity (Γ). The CMS NMs-based electrochemical sensing platform showed excellent analytical performance toward the OFX detection with two ultra-wide linear detection concentration ranges from 0.25-100 and 100-1000â µM, a low detection limit of 0.058â µM, and an excellent electrochemical sensitivity (0.743â µA µM-1 cm-2).
ABSTRACT
<b>Background and Objective:</b> Basil (<i>Ocimum basilicum</i> L.), an aromatic herb, is considered one of the most important crops with essential oils as well as other bioactive compounds. Basil leaves have tremendous pharmaceutical benefits and are used for foods. Slow-release fertilizers have been developed to optimize the fertilization of crops. This work aims to discover the effect of NPK Slow-Release Fertilizer Coated by Starch (NPK-SRFS) at different rates on growth, yield and essential oil components of basil grown on the field in Northern Vietnam. <b>Materials and Methods:</b> Basil seedlings, sown from seeds, were used as plant materials. NPK-SRFS was stocked in the Faculty of Chemistry, Hanoi Pedagogical University 2. The experiments were designed in a fully randomized block model, consisting of four treatments with different rates of NPK-SRFS. Each treatment had three replicates with an area of 8 m<sup>2</sup>. Duncan's Multiple Range Test was being used for statistical analysis (p = 0.05). <b>Results:</b> All 3 NPK-SRFS treatments significantly increased the number of buds and leaves per plant compared to the control. However, NPK-SRFS at different rates affected diversely plant height and leaf area of the basil. F5.0 and F10 treatments accelerated chlorophyll content as well as Fv/Fm value in comparison with none NPK-SRFS treatment. The application of NPK-SRFS at different rates caused slightly different changes in basil essential oil composition, especially the content of Methyl Chavicol, the most abundant oxygenated monoterpene and α-trans-Bergamotene, the most abundant sesquiterpene hydrocarbon. <b>Conclusion:</b> The present study provides further insight into the influence of NPK-SRFS on the growth, yield and essential oil components of basil.
