Oxidation Of Ofloxacin Research Articles

Cu-doped waste-tire carbon as catalyst for UV/H2O2 oxidation of ofloxacin.

Ofloxacin (OFX), commonly employed in the treatment of infectious diseases, is frequently detected in aquatic environments and poses potential ecological risks. UV/H2O2 oxidation has been recognized as an efficient approach for removing antibiotics. In this study, Cu-doped waste-tire carbon was prepared and used as a UV/H2O2 catalyst for the degradation of OFX. The results showed that the OFX removal was 89.3% within 90min under the optimal reaction conditions. It was found that ZnO, used in the tire manufacturing to promote rubber vulcanization for enhanced stability and durability, played an important role in UV/H₂O₂ oxidation for OFX degradation. Toxicity experiments conducted with a microbial degradation respirometer demonstrated that the treated water exhibited low toxicity. This study introduces a sustainable catalyst derived from waste tires, and facilitating the development of metal-carbon catalysts for the effective removal of antibiotics from wastewater.

Electrochemical degradation of ofloxacin using PbO2/Pb-based lead acid battery electrode: Parametric optimization and kinetics study

In this study, PbO2/Pb-based electrode used in commercial lead-acid battery was applied for electrochemical oxidation (ECO) of ofloxacin (OFX) in aqueous phase. Surface topography of PbO2/Pb electrode material was analysed to access surface morphology composed of Pb and oxygen elements of PbO2 through scanning electron microscopy analysis and energy dispersive X-ray analysis. Electrochemical characterization like linear sweep voltammetry analysis, oxygen evolution potential determined as 1.25 V for PbO2/Pb electrode. A high oxidation peak current obtained in cyclic voltammetry analysis suggest that oxidation of OFX with help of produced hydroxyl (●OH) reactive species. Parametric optimization of various process parameters in ECO process was conducted to determine maximum efficacy of process. Maximum OFX removal (85 %) was obtained under the optimum conditions of (initial concentration of OFX:100 ppm, current density: 50 mA/cm2, Na2SO4 electrolyte concentration: 0.1 M Na2SO4 and pH:4). Maximum Chemical oxygen demand (COD) removal (65 %) is obtained when 18 kWh (kg COD removed) −1 of electrical energy was used in ECO process for OFX degradation. Reusability test conducted for used PbO2/Pb electrode indicates that the electrode is stable and can be used repeatedly up to 5 repeated cycles with a minimum 20 % loss in removal %.

Design of 2D/2D CoAl LDH/g-C3N4 heterojunction-driven signal amplification: Fabrication and assay for photoelectrochemical aptasensor of ofloxacin

Ofloxacin (OFL), as a typical third-generation fluoroquinolone antibiotic, has been widespread employed in applications of preventing and treating skin tissue and bacterial infections. Detection of the residual OFL in water environment is extremely urgent on account of its toxicity to human body. Herein, a photoelectrochemical (PEC) aptasensor has been developed and fabricated for OFL determination based on CoAl layered double hydroxide/graphitic carbon nitride (CoAl LDH/g-C3N4) with two-dimensional/two-dimensional (2D/2D) structure. Strongly coupled 2D/2D structure with closed-connected contact can be beneficial to the formation of large numbers of high-speed transfer channels at the interfacial heterojunction, thereby shortening the transmission distance of carriers. Photocurrent signal of 2D/2D CoAl LDH/g-C3N4 heterojunction realized the remarkable amplification, endowing it excellent PEC performance. Based on the oxidation of OFL by photoinduced holes, this developed aptasensing platform exhibited a wide linearity range of 1 × 10–2~1 × 105 pmol L–1 with a low limit detection of 3.4 fmol L–1, along with anti-inference and feasibility for OFL assay in actual water samples. This design can be proposed by the layered structure materials coupled with g-C3N4 to significantly amplify the photocurrent signal, which opens the way for the field of PEC analysis and environmental pollutants detection.

Kinetic Spectrophotometric Method for the Estimation of Ofloxacin in Pharmaceutical Formulations

The objective of the current study was to develop a direct, sensitive spectrophotometric method based on the oxidation of Ofloxacin using potassium permanganate in alkaline medium. The rate of change of absorbance was measured at 603 nm. The initial rate method and fixed time method (at 4 min) are utilised to construct calibration graphs for calculating the concentration of the drug. The results were validated through inter day and intraday precision assays according to the ICH guidelines and also through recovery studies. Statistical comparison of the proposed methods with that of reference method shows excellent agreement and indicates no significant difference in their accuracy and precision.

Electrochemical Sensor Based on a Novel Pt−Au Bimetallic Nanoclusters Decorated on Reduced Graphene Oxide for Sensitive Detection of Ofloxacin

AbstractPt−Au nanoclusters decorated on the surface of reduced graphene oxide (rGO/Pt−Au) was facilely prepared by one‐pot electrochemical reduction. The morphology and composition of rGO/Pt−Au composites had been characterized by scanning electron microscopy (SEM) coupled with energy‐dispersive X‐ray spectrometry (EDX), fourier transform‐infrared spectroscopy (FT‐IR) and electrochemical methods. Ofloxacin is a member of synthetic quinolones which has been widely used for the treatment of common diseases in humans and animals. The performance of the rGO/Pt−Au nanocomposite toward the oxidation of ofloxacin was compared with the other similar nanostructures like rGO/Pt and rGO/Au. In the optimized conditions, two linear calibration curves were obtained, from 0.08 to 10 μM and 10 to 100 μM ofloxacin. A detection limit of 0.05 μM ofloxacin was observed at pH 5.7 for the GCE/rGO/Pt−Au. The proposed sensor was successfully applied to determine ofloxacin in tablets and human urine samples and the results were satisfactory.

Oxidation of ofloxacin by Oxone/Co2+: identification of reaction products and pathways

Oxidative degradation of ofloxacin (OFX) by sulfate free radicals (SO4 (-•)) in the UV/Oxone/Co(2+)oxidation process was investigated for the first time, with a special focus upon identifying the transformation products as well as understanding the reaction pathways. Thirteen main compounds were identified after the initial transformation of OFX; the detailed structural information of which were characterized by high-performance liquid chromatography-high resolution mass spectrometry and MS fragmentation analysis. The degradation pathways mainly encompassed ring openings at both the piperazinyl substituent and the quinolone moiety, indicating that the usage of SO4 (-•) aided the oxidative degradation of OFX to undergo more facile routes compared to those in previous reports by using OH(•)/h(+) as the oxidant, where the initial transformation attacks were mainly confined to the piperazine moiety. Moreover, in this study, smart control over the pH conditions of the oxidation system via different modes of Oxone dosage resulted in the selective degradation of the functional sites of OFX molecule, where it was shown that the SO4 (-•)-driven destruction of the quinolone moiety of OFX molecule favored the neutral pH conditions. This would be beneficial for the reduction of bacterial resistance against quinolones in the aqueous environment.

Light-induced catalytic transformation of ofloxacin by solar Fenton in various water matrices at a pilot plant: Mineralization and characterization of major intermediate products

This work investigated the application of a solar driven advanced oxidation process (solar Fenton), for the degradation of the antibiotic ofloxacin (OFX) in various environmental matrices at a pilot-scale. All experiments were carried out in a compound parabolic collector pilot plant in the presence of doses of H2O2 (2.5mgL−1) and at an initial Fe2+ concentration of 2mgL−1. The water matrices used for the solar Fenton experiments were: demineralized water (DW), simulated natural freshwater (SW), simulated effluent from municipal wastewater treatment plant (SWW) and pre-treated real effluent from municipal wastewater treatment plant (RE) to which OFX had been spiked at 10mgL−1. Dissolved organic carbon removal was found to be dependent on the chemical composition of the water matrix. OFX mineralization was higher in DW (78.1%) than in SW (58.3%) at 12mgL−1 of H2O2 consumption, implying the complexation of iron or the scavenging of hydroxyl radicals by the inorganic ions present in SW. On the other hand, the presence of dissolved organic matter (DOM) in SWW and RE, led to lower mineralization per dose of H2O2 compared to DW and SW. The major transformation products (TPs) formed during the solar Fenton treatment of OFX, were elucidated using liquid chromatography–time of flight-mass spectrometry (LC–ToF-MS). The transformation of OFX proceeded through a defluorination reaction, accompanied by some degree of piperazine and quinolone substituent transformation while a hydroxylation mechanism occurred by attack of the hydroxyl radicals generated during the process leading to the formation of TPs in all the water matrices, seven of which were tentatively identified. The results obtained from the toxicity bioassays indicated that the toxicity originates from the DOM present in RE and its oxidation products formed during the photocatalytic treatment and not from the TPs resulted from the oxidation of OFX.

Titrimetric assay of ofloxacin in pharmaceuticals using cerium(IV) sulphate as an oxidimetric reagent

Two titrimetric methods which are simple, rapid, cost-effective and eco-riendly are described for the determination of ofloxacin (OFX) in bulk drug and in tablet formulations based on the oxidation of OFX by Ce(IV) sulphate. In direct titrimetry (method A), the acidified solution of OFX is titrated directly with Ce(IV) sulphate using ferroin as indicator, and indirect titrimetry (method B) involves the addition of known excess of Ce(IV) sulphate to an acidified solution of OFX followed by the determination of unreacted oxidant by back titration with ferrous ammonium sulphate (FAS) using the same ferroin indicator. In both the methods, the amount of Ce(IV) sulphate reacted corresponds to OFX concentration. Method A and method B permit the determination of OFX over the concentration range of 1.5–15 mg in both the methods and the quantitation is based on a 1: 5 reaction stoichiometry (OFX: Ce (IV) sulphate). The methods were statistically evaluated by calculating percent relative error (% RE) for accuracy and percent relative standard deviation (% RSD) for precision, and were applied successfully to the determination of OFX in tablets with mean recoveries in the range of 96.50–98.42%. No interference was observed from common additives found in pharmaceutical preparations. The accuracy and reliability of the methods were further ascertained by performing recovery tests s standard-addition technique.

Spectrophotometric determination of ofloxacin in pharmaceuticals by redox reaction

Two simple spectrophotometric methods have been developed to analyze ofloxacin (OFX) in pharmaceuticals. The methods are based on the oxidation of OFX by a measured excess of cerium(IV) sulfate in H(2)SO(4) medium. This was followed by the determination of the unreacted oxidant by reacting it with either p-toluidine (p-TD) and measuring the absorbance at 525 nm (method A) or o-dianisidine (o-DA) and measuring the absorbance at 470 nm (method B). In both methods, the amount of cerium(IV) sulfate reacted corresponds to the amount of OFX. Calibration graphs were linear over the ranges of 0-120 and 0-4 g/ml OFX for methods A and B, respectively. The calculated molar absorptivity (2.34.10(3) and 5.99.10(4)), Sandell sensitivity, and limit of quantification for the methods are reported. The intra-day precision (%RSD) and accuracy (%RE) were < 8.0 and <= 4.0%, respectively, and the inter-day RSD and RE values were within 5 and 4.0%, respectively. The applicability of the methods was demonstrated by determining OFX in tablets with an accuracy (%RE) of < 3% and precision (%RSD) of <= 2.65%. The accuracy of the methods was further ascertained by recovery experiments via a standard-addition procedure.

Electrochemical study on oxidation of ofloxacin at nano-ZnS/poly (Styrene sulfonic acid sodium salt) modified electrode and its interaction with calf thymus DNA

A PSS/nano-ZnS thin film modified electrode has been fabricated on the surface of glassy carbon electrode (GCE). In pH 5.0 phosphate buffer solution (PBS), Ofloxacin (OFX) appeared as an anodic peak with the peak potential of 1.28 V at PSS/nano-ZnS film modified electrode. In comparison with a bare GCE or a nano-ZnS modified electrode, the PSS/nano-ZnS film modified electrode exhibited an enhanced effectiveness for the oxidation of OFX. Cyclic voltammetry (CV) coupled with fluorescence and UV-vis absorbance spectra techniques were used to study the interaction of OFX with Calf thymus DNA (ctDNA). The interaction of OFX and ctDNA could result in a considerable decrease in the peak currents and positively shift in the peak potential, as well as changes of fluorescence, UV-Vis adsorption spectra. All acquired data showed that the new adduct between OFX and ctDNA was formed.