A metal-organic framework signaling probe-mediated immunosensor for the economical and rapid determination of enrofloxacin in milk

Ensuring the safety of animal-derived foods requires the reliable and swift identification of enrofloxacin residues to monitor the presence of antibiotics. In this regard, we synthesized, tuned, and investigated the optical properties of a bimetallic metal-organic framework (Ce/Zr-UiO 66). The investigation was facilitated by employing a polydopamine-coated pipette tip with high adsorption efficiency, serving as an immunoreactive carrier. Subsequently, an immunofunctionalized variant of Ce/Zr-UiO 66, referred to as Ce/Zr-UiO 66@ Bovine serum albumin-enrofloxacin, was developed as an optical probe for the rapid and sensitive identification of enrofloxacin across a variety of samples. The method can accurately detect enrofloxacin at concentrations as low as 0.12 ng/mL, with a determination time of under 15 min; furthermore, it demonstrates exceptional efficacy when applied to food, environmental, and clinical samples. The implementation of this methodology offers a valuable means for cost-effective, rapid, and on-site enrofloxacin determination.

"Two-in-One" PtPdCu Trimetallic Multifunctional Nanoparticles-Mediated Dual-Signal-Integrated Aptasensor for Ultradetection of Enrofloxacin

Balancing the accuracy and simplicity of aptasensors is a challenge in their construction. This study addresses this issue by leveraging the remarkable loading capacity and peroxidase-like catalytic activity of PtPdCu trimetallic nanoparticles, which reduces the reliance on precious metals. A dual-signal readout aptasensor for enrofloxacin (ENR) detection is designed, incorporating DNA dynamic network cascade reactions to further amplify the output signal. Exploiting the strong loading capacity of PtPdCu nanoparticles, they are self-assembled with thionine (Thi) to form a signal label capable of generating signals in two independent modes. The label exhibits excellent enzyme-like catalytic activity and enhances electron transfer capabilities. Differential pulse voltammetry (DPV) and square-wave voltammetry (SWV) are employed to independently read signals from the oxidation-reduction reaction of Thi and the catalytic oxidation of hydroquinone (HQ) to benzoquinone (BQ) by H2O2. The introduced DNA dynamic network cascade reaction modularizes sample processing and electrode surface signal generation, avoiding electrode contamination and efficiently increasing the output of the catalyzed hairpin assembly (CHA) cycle. Under optimized conditions, the developed aptasensor demonstrates detection limits of 0.112 (DPV mode) and 0.0203 pg/mL (SWV mode). Additionally, the sensor successfully detected enrofloxacin in real samples, expanding avenues for designing dual-mode signal amplification strategies.

Comparison of oriented and non-oriented antibody conjugation with AIE fluorescence microsphere for the immunochromatographic detection of enrofloxacin

Antibodies and labels were typically non-oriented conjugated in conventional immunochromatographic assays (ICAs). In this work, a C-terminal cysteine-tagged recombinant protein A (rPA) was conjugated in an oriented manner onto aggregation-induced emission fluorescence microsphere (AIEFM). The Fc fragment of anti-enrofloxacin monoclonal antibody (anti-ENR mAb) was then conjugated onto the rPA. The resulting oriented mAb-AIEFM probe was used in an ENR-ICA for the rapid detection of ENR, a widely abused animal drug. The ENR-ICA with the oriented probe saved 66.7% of anti-ENR mAb and 25% of ENR-bovine serum albumin, and had a limit of detection of 0.035 ng/mL, compared with 0.079 ng/mL for the non-oriented probe. The corresponding linear ranges of the ENR-ICA based on the oriented and non-oriented probes were 0.25-10 ng/mL and 0.1-2.5 ng/mL, respectively. This novel ICA based on the oriented probe has the potential to be used for sensitive and rapid detection in food safety.

High-performance SERS chips for sensitive identification and detection of antibiotic residues with self-assembled hollow Ag octahedra

High-performance SERS chips via self-assembled hollow Ag octahedra on PDMS were employed to achieve the sensitive identification and detection of antibiotic residues. The developed SERS chips were successfully applied in the detection of ciprofloxacin (CIP), amoxicillin (AMX) and cefazolin (CZL) in wastewater and tap water samples, as well as enrofloxacin (ENR) in milk, demonstrating the sensitive determination of antibiotics in the real environment. From this perspective, these SERS chips are expected to expand the on spot sensitive detection and identification field of antibiotic residues.

The antibiotic resistance and risk heterogeneity between urban and rural rivers in a pharmaceutical industry dominated city in China: The importance of social-economic factors

Rivers are important environmental sources of human exposure to antibiotic resistance. Many factors can change antibiotic resistance in rivers, including bacterial communities, human activities, and environmental factors. However, the systematic comparison of the differences in antibiotics resistance and risks between urban rivers (URs) and rural rivers (RRs) in a pharmaceutical industry dominated city is still rare. In this study, Shijiazhuang City (China) was selected as an example to compare the differences in antibiotics resistance and risks between URs and RRs. The results showed higher concentrations of total quinolones (QNs) antibiotics in both water and sediment samples collected from URs than those from RRs. The subtypes and abundances of antibiotic resistance genes (ARGs) in URs were significantly higher than those in RRs, and most emerging ARGs (including OXA-type, GES-type, MCR-type, and tet(X)) were only detected in URs. The ARGs were mainly influenced by QNs in URs and social-economic factors (SEs) in RRs. The composition of the bacterial community was significantly different between URs and RRs. The abundance of antibiotic-resistant pathogenic bacteria (ARPBs) and virulence factors (VFs) were higher in URs than those in RRs. Therein, 371 and 326 pathogen types were detected in URs and RRs, respectively. Most emerging ARGs showed a significantly positive correlation with priority ARPBs. Variance partitioning analysis revealed that SEs were the main driving factors of ARGs (80 %) and microbial communities (92 %) both in URs and RRs. Structural equation models indicated that antibiotics (QNs) and microbial communities were the most direct influence of ARGs in URs and RRs, respectively. The cumulative resistance risk of QNs was high in URs, but relatively low in RRs. Enrofloxacin and flumequine posed the highest risk in water and sediment, respectively. This study could help us to better manage and control the risk of antibiotic resistance in different rivers.

A high-precision prediction for spatiotemporal distribution and risk assessment of antibiotics in an urban watershed using a hydrodynamic model

A methodology for the high-precision prediction and risk assessment of antibiotics at the watershed scale was established. Antibiotic emission inventory and attenuation processes were integrated into the MIKE 11 model to predict the spatiotemporal distribution of norfloxacin, ofloxacin, enrofloxacin, erythromycin, roxithromycin, and sulfamethoxazole in the Nanfei River watershed, China. Considering the variations in antibiotic removal in sewage treatment plants, manure composting, and lagoon systems, the high, medium, and low removal efficiencies of selected antibiotics across China were obtained and used as the best, expected, and worst scenarios, respectively, to evaluate the uncertainty of antibiotic emissions. The predicted concentrations were comparable to antibiotic measurements after flow calibration. The prediction results showed that the highest concentration exposures were mainly concentrated in urban areas with a dense population. Flow variations controlled the temporal distribution characteristics of antibiotics via the dilution effect, and the concentrations of antibiotics in the dry season were 3.1 times higher than those in the wet season. The median concentrations of norfloxacin and erythromycin ranged from 111.36 ng/L to 592.33 ng/L and 106.63 ng/L to 563.01 ng/L, respectively, which both posed a high risk to cyanobacteria and a medium risk to spreading antibiotic resistance. Scenario analysis further demonstrated that high removal efficiencies of these antibiotics can considerably reduce the potential ecotoxicity risks and bacterial resistance selection. The developed methodology for predicting the distribution and risk of antibiotics was suitable for the risk assessment and control strategy of human- and livestock-sourced pollutants.

Association between fluoroquinolone exposure and children's growth and development: A multisite biomonitoring-based study in northern China

BACKGROUND

Although animal experiments found that antibiotic exposure during early life increased adiposity, limited human epidemiological evidence is available for the effects of veterinary antibiotic exposure on children's growth and development.

OBJECTIVE

This study was conducted to examine the body burden of fluoroquinolones in northern Chinese children and assess its association with growth and development.

METHODS

After recruiting 233 children aged 0-15 years from 12 different sites in northern China in 2020, we measured urinary concentrations of 5 respective fluoroquinolones (fleroxacin, ofloxacin, norfloxacin, ciprofloxacin, and enrofloxacin) by high performance liquid chromatography. Categories of children's growth and development were identified based on the Z score of body mass index. The health risks of individual and combined antibiotic exposure were estimated by the hazard quotient (HQ) and hazard index (HI), respectively. The association between children's growth and development with antibiotic concentrations was evaluated via multiple logistic regression analysis.

RESULTS

In total, 4 antibiotics, fleroxacin, ofloxacin, ciprofloxacin, and enrofloxacin, were found in urine samples of northern Chinese children at an overall frequency of 57.08%. Due to diet and economic differences, antibiotic concentrations in urine samples differed by study area, and the highest concentrations were found in Tianjin, Henan, and Beijing. The percentage of the participants with HQ > 1 caused by ciprofloxacin exposure was 20.61%, and the HI values in 23.18% of samples exceeded 1, suggesting potential health risks. The odds ratio (95% confidence interval) of overweight or obesity risk of tertile 2 of enrofloxacin was 3.01 (1.12, 8.11), indicating an increase in overweight or obesity risk for children with middle-concentration enrofloxacin exposure.

CONCLUSION

This is the first study to show a positive association of enrofloxacin internal exposure with overweight or obesity risk in children, demonstrating that more attention should be given to the usage and disposal of fluoroquinolones to safeguard children's health.

Activation of persulfate by a water falling film DBD process for the enhancement of enrofloxacin degradation

A synergetic system of water falling film dielectric barrier discharge (DBD) plasma and persulfate (PS) was established and applied to enhance the enrofloxacin (EFA) degradation in this study. The simultaneous existence of electrons, reactive species, heat and UV-visible light in the DBD plasma system were utilized together to activate the PS to form SO₄^-· and other reactive oxygen species (ROS), and then worked in synergy with the DBD plasma to oxidize the EFA. The obtained results verified that there was a significant increase in the degradation percentages of EFA (20 mg L^-1) in the DBD/PS system, and the trend was more obvious under the condition of larger discharge power input. When 0.8 mM PS was added into the DBD system with 0.8 kW discharge power, the degradation percentage of EFA could reach 99.35% after 60 min treatment, the corresponding synergetic factor (SF) was 7.94. Analysis of the O₃ and the H₂O₂ concentrations in the DBD plasma system before and after the PS addition explained the activation of the PS by the HO·. The quenching experiments on reactive species suggested that SO4^-·, HO·, and ¹O₂ were all important reactive species for EFA degradation. The intermediates formed by the EFA degradation were detected and the degradation pathways were speculated. Results of toxicity analysis illustrated that the toxicity of the initial EFA solution decreased after degradation in the synergetic system of DBD/PS.

Metabolites in Milk after Enrofloxacin Treatment and Their Persistence to Temperature

In this work, metabolomic profile changes in milk from cows affected by mastitis and treated with enrofloxacin (ENR) have been studied using LC-HRMS techniques. Principal component analysis was applied to the obtained results, and the interest was focused on changes affecting compounds without a structural relationship to ENR. Most of the compounds, whose concentrations were modified as a result of the pharmacological treatment and/or the pathological status, were related to amino acids and peptides. Compounds that may become possible biomarkers for either disease or treatment have been detected. Additionally, the alterations caused by thermal processes, such as those applied to milk before consumption, on the identified metabolites have also been considered.

Uptake of Pharmaceutical Pollutants and Their Metabolites from Soil Fertilized with Manure to Parsley Tissues

Manure is a major source of soil and plant contamination with veterinary drugs residues. The aim of this study was to evaluate the uptake of 14 veterinary pharmaceuticals by parsley from soil fertilized with manure. Pharmaceutical content was determined in roots and leaves. Liquid chromatography coupled with tandem mass spectrometry was used for targeted analysis. Screening analysis was performed to identify transformation products in the parsley tissues. A solid-liquid extraction procedure was developed combined with solid-phase extraction, providing recoveries of 61.9–97.1% for leaves and 51.7–95.6% for roots. Four analytes were detected in parsley: enrofloxacin, tylosin, sulfamethoxazole, and doxycycline. Enrofloxacin was detected at the highest concentrations (13.4–26.3 ng g⁻¹). Doxycycline accumulated mainly in the roots, tylosin in the leaves, and sulfamethoxazole was found in both tissues. 14 transformation products were identified and their distribution were determined. This study provides important data on the uptake and transformation of pharmaceuticals in plant tissues.

Novel electrochemical sensor modified with molecularly imprinted polymers for determination of enrofloxacin in marine environment

Molecularly imprinted polymers were synthesized by gel-sol method with multi-walled carbon nanotubes as support and enrofloxacin as a template and further modified on the surface of glassy carbon electrode to construct a molecularly imprinted electrochemical sensor. The performance of the imprinted electrochemical sensor was thoroughly investigated by using cyclic voltammetry and differential pulse voltammetry. The influence of imprinted polymers amount, electrolyte pH, and incubation time on the sensor performance was investigated for the detection of enrofloxacin. Under the optimal experimental conditions in a three-electrode system with the modified electrode as the working electrode the differential pulse voltammetry response current of the sensor had a good linear relationship at 0.2 V (vs. saturated calomel reference electrode) with the enrofloxacin concentration within 2.8 pM-28 μM and the limit of detection of the method was 0.9 pM. The competitive interference experiment showed that the imprinted electrochemical sensor could selectively recognize enrofloxacin. The method was applied to analyze spiked natural seawater, fish, and shrimp samples. The recovery was 96.4%-102%, and RSD was less than 4.3% (n = 3), indicating that the proposed imprinted electrochemical sensor was suitable for the determination of trace enrofloxacin in marine environment samples.

Elucidating the catalytic degradation of enrofloxacin by copper oxide nanoparticles through the identification of the reactive oxygen species

Copper oxide nanoparticles (CuO-NPs) have been suggested as effective catalysts to degrade many persistent organic contaminants. In parallel, CuO-NPs are considered toxic to soil microorganisms, plants and human cells, possibly because they induce oxidative stress and generation of reactive oxygen species (ROS). However, the mechanism of the catalytic process and the generated ROS are poorly understood. Here we discuss the reaction mechanism of CuO-NPs during the catalytic degradation of enrofloxacin - an antibiotic pharmaceutical used in this study as a representative persistent organic compound. The degradation of an aqueous solution of the enrofloxacin exposed to CuO-NPs and hydrogen peroxide was studied showing fast removal of the enrofloxacin at ambient conditionsns. ROS production was identified by electron spin resonance and a spin trapping technique. The distribution of the free radical species indicated production of a high percentage of superoxide (O₂^-.) radicals as well as hydroxyl radicals; this production is similar to the "radical production" activity of the superoxide dismutase (SOD) enzyme in the presence of hydrogen peroxide. This activity was also tested in the opposite direction, to examine if CuO-NPs show reactivity that potentially mimics the classical SOD enzymatic activity. The CuO-NPs were found to catalyze the dismutation of superoxide to hydrogen peroxide and oxygen in a set of laboratory experiments.

Individual and combined effects of amoxicillin, enrofloxacin, and oxytetracycline on Lemna minor physiology

We investigated individual and combined effects of environmentally representative concentrations of amoxicillin (AMX; 2 μg l^-1), enrofloxacin (ENR; 2 μg l^-1), and oxytetracycline (OXY; 1 μg l^-1) on the aquatic macrophyte Lemna minor. While the concentrations of AMX and ENR tested were not toxic, OXY decreased plant growth and cell division. OXY induced hydrogen peroxide (H₂O₂) accumulation and related oxidative stress through its interference with the activities of mitochondria electron transport chain enzymes, although those deleterious effects could be ameliorated by the presence of AMX and/or ENR, which prevented the overaccumulation of ROS by increasing catalase enzyme activity. L. minor plants accumulated significant quantities of AMX, ENR and OXY from the media, although competitive uptakes were observed when plants were submitted to binary or tertiary mixtures of those antibiotics. Our results therefore indicate L. minor as a candidate for phytoremediation of service waters contaminated by AMX, ENR, and/or OXY.

Exposure pathways and ecological risk assessment of common veterinary antibiotics in the environment through poultry litter in Bangladesh

Veterinary antibiotics (VAs) have entered the ecosystem principally through the application of organic fertilizer. However, factors influencing the contributions made by the prescribers and users thereof with respect to VAs in poultry manure have not been investigated. The purpose of this paper, therefore, is to identify factors associated with the VA prescription and usage as well as to measure the residual concentration along with the ecological risk of common VAs in poultry litter in Bangladesh. Structured questionnaire surveys were conducted so as to provide an understanding the perspective of prescribers and farmers. Ciprofloxacin (CIP), enrofloxacin (ENR), oxytetracycline (OTC), and doxycycline (DOX) were screened through the use of thin-layer chromatography (TLC) and quantified through high-performance liquid chromatography (HPLC). Also, methods of risk quotient (RQ) were applied to assess ecotoxicity. Most VAs were prescribed without a confirmatory diagnosis. The residue of CIP was dominant with a high concentration, followed by OTC but with a low concentration. A high ecological risk was associated with the use of OTC and DOX whereas the risk associated with the use of CIP and ENR was insignificant to low. The study highlights prescriber and user factors along with the variable ecological risk of VAs in litter.

Fluoroquinolones and trace elements in poultry litter: estimation of environmental load based on nitrogen requirement for crops

Poultry litter soil application contributes to sustainability of agricultural systems and is in accordance with the United Nations Sustainable Development Goals (UN-SDG). Poultry litter recommended rates are based on crop nitrogen (N) needs, however, their application can be a potential source of antibiotics and trace elements overload. The aim of the study was to estimate the role of poultry litter application on soil contamination by fluoroquinolones [enrofloxacin (ENR) and ciprofloxacin (CIP)] and trace elements, based on N requirements for crops. Analytical and sampling techniques were used to estimate the loads from poultry litter application. Only CIP was found in poultry litter samples (283 ± 124 µg kg^-1) and its load was estimated to be of 9.89 ± 4.33 g ha^-1, for the poultry litter application (35 t ha^-1). The estimated loads (g ha^-1) of trace elements were: Cr 9.19 ± 3.26, Ni 12.3 ± 4.93, Pb 22.0 ± 8.26, Cu 229 ± 85.6, Mn 691 ± 259 and Zn 1,011 ± 378. These estimates were 900% higher than those recommended by the technical guidance, while N exceeded 600% the recommended application. In order to achieve UN-SDGs, local policies to disseminate knowledge and technologies are required for consolidating sustainable agricultural practices.

Toxicity of enrofloxacin and cadmium alone and in combination to enzymatic activities and microbial community structure in soil

Antibiotics and heavy metals have long-term potential toxicity to the environment, and their residuals in agricultural soils are receiving more and more attention. To evaluate the ecotoxicological effects of enrofloxacin and cadmium on soil enzymatic activities and microbial community structure, soil samples were exposed to individual and combined contaminants over 28 days. The results indicated that the toxic effects of enrofloxacin alone on soil enzymatic activities were relatively small and showed no concentration dependence. In contrast, significant inhibition of soil enzymatic activities was observed upon cadmium contamination by itself. Overall, the combination of two contaminants also has toxic effect on enzymatic activities; an antagonism between enrofloxacin and cadmium was observed. On 14 and 21 days, individual enrofloxacin and cadmium reduced average well color development (AWCD), Shannon, McIntosh, Simpson indices, and substrate utilization, except for Shannon, McIntosh, Simpson indices of the cadmium 0.4 mmol/kg treatment were higher than the control on 21 days. In general, combined treatments led to higher value of these microbial diversity indicators than those found under separate contamination, although there were some exceptions. With the increase in enrofloxacin concentration, the utilization of any carbon source by the microorganisms gradually decreased. In addition, the AWCD value and substrate utilization decreased as time increased. In the separate and combined contaminant treatments, the order of substrate utilization by soil microorganisms was aliphatics > amino acids > saccharides > metabolites. Thus, enrofloxacin and cadmium had a variable but generally negative influence on soil enzymatic activities and microbial community structure.

High-sensitive imprinted membranes based on surface-enhanced Raman scattering for selective detection of antibiotics in water

Poly(vinylidene fluoride) (PVDF) is known as one of the widely used membrane separation materials with excellent physical and chemical properties. In this work, we combine surface-enhanced Raman scattering (SERS) detection technology, membrane separation technology and molecular imprinting technology (MIT) to improve sensitivity and selectivity for selective detection of the enrofloxacin hydrochloride in water. In this investigation, PVDF membranes were used as the support materials and different experiment parameters were investigated to obtain the best property. Meanwhile, the Ag nanoparticles (Ag NPs) modified by 3-methacryloxypropyltrimethoxysilane (KH-570) were used as the SERS substrates and they were uniformly dispersed on the surface of the membrane. Finally, Ag-based SERS imprinted membranes (ASIMs) with specific recognition property were successfully prepared with enrofloxacin hydrochloride as the template molecule, acrylamide (AM) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker agent and 2,2'-azobis(2-methylpropionitrile) (AIBN) as the initiator by a facile and versatile precipitation polymerization strategy. Under the optimal condition, it was presented good linear relationship (R² = 0.994) between the Raman signal (at 1390.8 cm^-1) and the concentration (10^-3 mol·L^-1-10^-7 mol·L^-1) of the templates, and the limit of detection was determined as 10^-7 mol·L^-1. The morphology and characters were investigated and the results proved that the SERS imprinted membranes could be used into the selective detection of antibiotics and it provided a novel approach of antibiotics detection.

Cetylpyridinium bromide assisted micellar-enhanced ultrafiltration for treating enrofloxacin-laden water

The presence of a fluoroquinolone base veterinary antibacterial drug enrofloxacin in aqueous media poses a major threat due to its ecotoxicity on aquatic microbiota. Hence, for the first time, an attempt was made to remove enrofloxacin (ENX) from its aqueous solution by employing micellar-enhanced ultrafiltration (MEUF) where cetylpyridinium bromide (CPB), a cationic surfactant was used for micellization. Response surface methodology (RSM) with central composite design (CCD) approach was applied to design the experiment, and to optimize the process parameters, namely, ENX concentration (3-15 mg/L), transmembrane pressure (2-6 kg_f/cm²), recirculation flow rate (5.5-7.5 L/min) and CPB concentration (1.4-4.2 mM). The objective of this study was to maximize the permeate flux and rejection coefficient and to find out the optimal process condition for the removal of enrofloxacin from aqueous solution. Though maximum 68.23 L/m² h of permeate flux and 94.20% of rejection coefficient were achieved at different process conditions, the optimization study reveals that the predicted optimal values of permeate flux and rejection coefficient are 67.53 L/m² h and 89.67% respectively. Modelling was also carried out with the aid of artificial neural network (ANN) to validate the prediction of RSM. The predictability of the model by RSM and ANN was compared statistically by evaluating root-mean-square error (RMSE), absolute average deviation (AAD) and mean absolute error (MAE), where ANN exhibited better predictability. The following set of parameters was proposed for industrial scale up: ENX concentration of 8.4 mg/L, TMP of 5 kg_f/cm², recirculation flow rate of 6 L/min and CPB concentration of 2.1 mM.

Presence and environmental risk assessment of selected antibiotics in coastal water adjacent to mariculture areas in the Bohai Sea

The presence and concentrations of 25 antibiotics in Dalian coastal water of the Bohai Sea were investigated using solid-phase extraction coupled with high-performance liquid chromatography tandem mass spectrometry. Results showed that antibiotics were widely detected in this region with total concentration ranging from 22.6 to 2402.4 ng/L. Enrofloxacin and trimethoprim were 100% detected followed by sulfamethoxazole with a detection rate of 90.9%. No significant correlations were found between antibiotics concentrations and sample parameters such as dissolved organic carbon, salinity, and distance from the coast, suggesting that concentrations and distributions of the antibiotics in this area were source-dependent. Antibiotic concentration in the sample from an offshore cage-culture area was the highest. Based on composition profiles, mariculture was supposed to be an important source of antibiotics. According to the assessment, individual antibiotic posed low to moderate risk, while the antibiotic mixture presented high risk. Enrofloxacin, clarithromycin and sulfamethoxazole, the top three contributors to the mixture risk quotients for each site, need priority control in this area. Besides, levels of enrofloxacin were high enough to exert a selective pressure on bacteria that may lead to an increase in the prevalence of resistance.

Fluorescent carbon dots based sensing system for detection of enrofloxacin in water solutions

Enrofloxacin (ENR) is one of the environmental pollutants need to remove in many wastewater treatment processes. Traditional methods for measuring ENR are often complex and time-consuming. Due to their low cost and high efficiency, fluorescent carbon dots can be used for detecting many pharmaceuticals. In this contribution, nitrogen doped fluorescent carbon dots (N-CDs) were firstly synthesized with a fluorescence quantum yield of 20.5%. The N-CDs can emit strong blue fluorescence when excited at 368 nm and there exist a large amount of carboxyl, hydroxyl and amine groups on their surfaces. In addition, the fluorescence of N-CDs could be quenched in the presence of Cu²⁺, which could be gradually restored upon adding ENR. Thereby, a rapid and sensitive fluorescent sensing strategy based on the fluorescence recovery of the N-CDs-Cu²⁺ system was designed for selective detection of ENR. The possible sensing mechanism was also proposed in terms of the results of resonance Rayleigh scattering, UV-vis absorption and Fourier transform infrared (FITR) spectra. Under the optimal condition, a good linear relationship was obtained for ENR determination with concentrations ranging from 1.0 to 15.0 μg·mL^-1 and the detection limit of 0.16 μg·mL^-1 was achieved. Finally the proposed sensing system was applied for the detection of ENR in real water samples with satisfactory results.

Comprehensive analysis on sorptive uptake of enrofloxacin by activated carbon derived from industrial paper sludge

The current investigation deals with how chemically activated carbon derived from industrial paper sludge (ACPS) performs on sorptive removal of enrofloxacin (ENF), an antibacterial drug from its water solution. Thermogravimetric (TGA) and proximate analysis of raw paper sludge (RPS) were conducted. ACPS was characterized with proximate analysis, XRD, FT-IR, SEM and BET. The influence of five operational parameters viz. adsorbate concentration (initial), dose of adsorbent, pH, temperature, and contact time on the adsorption of ENF onto ACPS has been conducted using batch experiments. The process of adsorption was optimized through ANN (artificial neural network) in addition to RSM (response surface methodology). The maximum percentage removal (95.85%) was achieved at initial ENF concentration 12 mg/g, adsorbent dose 1.2 g/L, contact duration of 18 h and temperature 20 °C. Kinetic data were best fitted into pseudo-second order kinetic model and adsorption equilibrium study indicates that the adsorption process follows Langmuir isotherm model. Adsorption capacity was noted to have a highest value of 44.44 mg/g. A study on thermodynamics of the adsorption process suggests that it exhibits spontaneity, being essentially exothermic. Cost analysis and reusability study confirm that adsorbent produced from industrial paper sludge is cost-effective and reusable. Therefore, ACPS as adsorbent has potency for removing ENF from aqueous solution.

Enrofloxacin and copper plant uptake by Phragmites australis from a liquid digestate: Single versus combined application

Application of anaerobically digested sludges and manure (digestates) to agricultural fields reduces the need for fertilizer application, but might also pose environmental risks due to the introduction of various pollutants -including metal trace elements and pharmaceuticals- to amended soils. The simultaneous presence of different contaminants can affect plant uptake, altering the performance of phytoremediation. This work aims to investigate and compare the single and combined effects of Enrofloxacin (Enro) and Cu on their plant uptake from digestate solutions. Plant uptake experiments were carried out by exposing, for 5 days, Phragmites australis to three different concentrations of a liquid digestate doped with Cu and/or Enro. Contaminant concentrations were afterward determined in both plant tissues and digestate solutions. Contaminant speciation in solution and Cu speciation in plant roots were also assessed. Cu plant uptake (mostly in plant roots, Cu concentration varied between 55 and 254 μg·g^-1) was observed, especially at low concentration of digestate. At high digestate concentration, Cu uptake decreased due to the formation of Cu-DOC complexes rendering Cu less bioavailable. The presence of the antibiotic slightly further reduced Cu plant uptake due to the formation of Cu-Enro complexes. Plant roots also accumulated Enro, an accumulation also higher for the lowest concentration of digestate (an increase of 40%), and that slightly increased in the presence of Cu (up to 226 μg·g^-1). However, proportion of free Enro in solution decreased (up to 70%) in the presence of Cu due to complexation. Cu speciation in plant roots confirmed the implication of the complexation in the uptake of Cu and Enro when they are simultaneously present in solution. Thus, the presence of amendments (such as digestates) increasing the DOC content, in addition to the interactions between contaminants, should be taken into account for field crop soils as well as for phytoremediation technologies.

Excessive use of enrofloxacin leads to growth inhibition of juvenile giant freshwater prawn Macrobrachium rosenbergii

Giant freshwater prawn Macrobrachium rosenbergii is an economically important species. However, its growth retardant have brought serious economic losses in recent years. Antibiotics abuse is suggested as a reason for M. rosenbergii's growth retardant, while few studies focused on the toxic effect of antibiotics on M. rosenbergii. To investigate the effect of enrofloxacin, a widely used antibiotic, on juvenile M. rosenbergii, a 14 days exposure study was carried out within 0.2, 1 and 5 mg/L enrofloxacin and followed by 7 days decontamination. Results showed that during the test period, enrofloxacin had the largest accumulation in juvenile shrimp at day 3, and gradually decreased at day 7 and 14, and almost all the drugs are cleared after 3 days decontamination. Short-term exposure to low dose enrofloxacin can promote the growth of juveniles. High dose enrofloxacin inhibited the growth of juvenile shrimp, to gill and liver damage, and induced apoptosis of the hepatopancreatic cells. These adverse effects was possibly caused by enrofloxacin-induced oxidative stress. Moreover, we also found the damage caused by high concentrations of enrofloxacin was irreversible in the short term. Collectively, these data indicated that enrofloxacin did affect the juvenile shrimp growth and development, and high level enrofloxacin abuse may contributed to M. rosenbergii's growth retardant.

Fluoroquinolones in agricultural soils: Multi-temporal variation and risks in Rio de Janeiro upland region

Our main goal was to investigate the potential accumulation of fluoroquinolones (FQs) in agricultural soils over extended periods of land use, predicting leaching and estimating risk quotients for soil microorganisms. Short to long-term of poultry litter fertilization (<1-30 years) were evaluated for enrofloxacin (ENR) and ciprofloxacin (CIP) input, in addition to the emergence of plasmid-mediated quinolone resistance (PMQR) genes. High FQs concentration (range 0.56-100 mg kg^-1) were measured in poultry litter samples. In soils, FQs occurrence and risks have changed over the years. An accumulation trend was observed between short and medium-term fertilized soils (ST and MT soils), reaching a range of 330-6138 μg kg^-1 ENR and 170-960 μg kg^-1 CIP in MT soil, followed by decreased concentrations in long-term fertilized soils (LT soils). The environmental risk assessment showed a high ENR risk quotient (RQ ≥ 1) in ST and MT soils ranging (7-226) and high CIP risk (9-53) in LT soils. The detection of qnrS genes in the area with the lowest FQs concentration emphasizes the importance of a broader approach to environmental assessment, in which not only target compounds are considered. FQs soil-water migration model pointed out a high leaching risk in ST soil. To reduce risks, management measures to decrease antibiotic environmental load should be taken before poultry litter application. In addition, the high weathering of tropical soils contributing to possible fate of antibiotics to water resources through drainage basins should be considered.

New and miniaturized method for analysis of enrofloxacin in palatable tablets

Enrofloxacin is an antimicrobial for oral use, from the fluoroquinolones of second-generation class, and it is the first fluoroquinolone used in veterinary for the treatment of bacterial infections. The development of trustworthy analytical methods has extreme importance for the assurance of safety, quality and therapeutic efficiency of pharmaceuticals. Previous articles in the literature describe several analytical methods for evaluation of enrofloxacin, but they do not use spectrophotometry in the visible region, nor use a miniaturized method or ecologically correct. In this work an analytical method for quantification of enrofloxacin in palatable tablets for veterinary prescriptions was developed and validated by spectrophotometry in the visible region. This method used a spectrophotometer UV-Vis BMG LabTechSpectrostar Nano, solution of iron chloride 0.5% as complexing agent, microplates and the analyses were conducted at 430 nm. The validation was conducted following international guides and showed linearity between the concentrations of 100 and 200 μg/ mL, selectivity, precision (intraday RSD 0.52%, interday RSD 0.44% and interanalyst RSD 0.56%), accuracy of 98.51% and robustness to time of analysis variation and wavelength. Therefore, the developed method approached the required parameters of validation and can be considered suitable for quantification of enrofloxacin in palatable tablets. The method also involves characteristics in green analytical chemistry for the current pharmaceutical analysis. This work contemplates a miniaturized, clean, innovator, fast and low cost method by spectrophotometry in the visible region for quantification of enrofloxacin in palatable tablets.

[Nanoscale Zero-valent Copper-Activated Molecular Oxygen for the Degradation of Enrofloxacin in Water]

Systematically studied the oxidation of enrofloxacin (ENR) in a nanoscale zero-valent copper (nZVC)-activated molecular oxygen system. The results show that nanoscale copper powder has a higher surface area than microscale copper powder, non-porous structure, and rough surface and exists in form of agglomerates. Nanoscale ZVC shows a superior activated performance toward molecular oxygen compared with microscale ZVC, which is due to its larger specific area and the fact that it corrodes easier. The H₂O₂ generated from the activation of molecular oxygen and the Cu⁺ released from surface corrosion form a novel Fenton-like system in which hydroxyl radicals are continuously produced, resulting in high-efficiency removal of ENR from water. The superoxide radicals produced during the reaction promote the reduction of Cu²⁺ to Cu⁺, thus speeding up the removal of ENR. The reaction conditions have a certain effect on the ENR degradation in nZVC-activated molecular oxygen systems. A higher nZVC dosage, lower ENR concentration, higher reaction temperature, and strong acidic conditions are favorable for the ENR removal.

A New Green Method for the Quantitative Analysis of Enrofloxacin by Fourier-Transform Infrared Spectroscopy

Background: A green analytical chemistry method was developed for quantification of enrofloxacin in tablets. The drug, a second-generation fluoroquinolone, was first introduced in veterinary medicine for the treatment of various bacterial species. Objective: This study proposed to develop, validate, and apply a reliable, low-cost, fast, and simple IR spectroscopy method for quantitative routine determination of enrofloxacin in tablets. Methods: The method was completely validated according to the International Conference on Harmonisation guidelines, showing accuracy, precision, selectivity, robustness, and linearity. Results: It was linear over the concentration range of 1.0-3.0 mg with correlation coefficients >0.9999 and LOD and LOQ of 0.12 and 0.36 mg, respectively. Conclusions: Now that this IR method has met performance qualifications, it can be adopted and applied for the analysis of enrofloxacin tablets for production process control. The validated method can also be utilized to quantify enrofloxacin in tablets and thus is an environmentally friendly alternative for the routine analysis of enrofloxacin in quality control. Highlights: A new green method for the quantitative analysis of enrofloxacin by Fourier-Transform Infrared spectroscopy was validated. It is a fast, clean and low-cost alternative for the evaluation of enrofloxacin tablets.