Oxytetracycline Research Articles

Mechanisms of manganese-tolerant Bacillus brevis MM2 mediated oxytetracycline biodegradation process

Addressing the environmental threat of oxytetracycline (OTC) contamination, this study harnesses the bioremediation capabilities of Bacillus brevis MM2, a manganese-oxidizing bacterium from acid mine drainage. We demonstrate the strain's exceptional efficiency in degrading OTC under high manganese conditions, with complete removal achieved within 24 h. The degradation is facilitated by the production of Bio-MnOx, utilizing their high redox potential and large specific surface area, which significantly enhance the adsorption and oxidation of OTC. Advanced characterization techniques, including X-ray diffraction, scanning electron microscopy, High Resolution-Transmission Electronic Microscope and X-ray photoelectron spectroscopy, provide a detailed analysis of the structural and functional properties of Bio-MnOx. The study also reveals the crucial role of Mn(III) intermediates and reactive oxygen species in the OTC degradation process, with quenching experiments validating their substantial impact on efficiency. Laccase activity, a key manganese-oxidizing enzyme, is assessed spectrophotometrically, further highlighting the enzymatic contribution to Mn(II) oxidation and OTC breakdown. This research contributes valuable insights and approaches for the targeted bioremediation of OTC-contaminated aquatic environments, offering a promising strategy for combating pollution from antibiotics and analogous compounds.

Biosurfactant-mediated transport of tetracycline antibiotics in saturated porous media: Combined effects of the chemical properties of contaminants and solution chemistry conditions

The mobility of tetracycline antibiotics (TCs) in saturated aquifers is possibly affected by the presence of biosurfactants, which are widespread in the aquatic/soil environments. This study investigated the mobility characteristics of various tetracyclines—specifically tetracycline (TC), oxytetracycline (OTC), and chlortetracycline (CTC)—within quartz sand columns in the presence of rhamnolipid, a common biosurfactant. Exogenous rhamnolipid significantly inhibited the transport of the three TCs over the pH range of 5.0–9.0 (e.g., the mass of retained TC, OTC, and CTC increased from 32.6 %, 26.9 %, and 39.2 % (in the absence rhamnolipid) to 39.4 %, 38.9 %, and 51.7 % (in the presence of rhamnolipid), respectively). This observation could be attributed to the bridging effects of this biosurfactant. Specifically, the hydrophilic head of rhamnolipid molecules is likely associated with the surfaces of sand grains through surface complexation and/or hydrogen bonding interactions. Accordingly, the hydrophobic moieties of the deposited rhamnolipid molecules (i.e., the aliphatic chains) interact with the hydrophobic groups of TCs molecules via hydrophobic interactions. Interestingly, the extent of the inhibitory effect on CTC mobility was greater than that on OTC and TC, which was related to the different hydrophobic characteristics of the three antibiotics. Furthermore, the inhibitory effect of rhamnolipid on the transport of TCs diminished as the pH of the background solution increased. This observation was attributed to the weakened bridging effects, resulting from the reduced deposition of the biosurfactant on the sand surfaces. Additionally, the cation-bridging mechanism involved in the retention of TCs in the addition of rhamnolipid when the background electrolyte was Ca2+ (i.e., Ca2+ ions served as bridging agents between the deposited rhamnolipid molecules and TCs). The insightful findings enhance our understanding of the critical roles of biosurfactants in influencing the environmental dynamics and ultimate fate of conventional antibiotic pollutants within groundwater systems.

Highly efficient MIL-53(Al)@Biomass hybrid for oxytetracycline elimination: Adsorption, LED-induced photocatalysis and pyrolytic recycling

The presence of antibiotics in water discharges represents a hazard for the ecosystems, as it could affect the biota equilibrium at the micro and macroscales. Consequently, it is crucial to develop effective adsorption and oxidation technologies to remove antibiotics from water. Herein, we assessed the effectivity and stability of a metal organic framework-biomass hybrid (MIL-53(Al)@RH) for the removal of oxytetracycline (OTC) via adsorption and photocatalytic degradation. Under equilibrated conditions, the hybrid retained 165mgg−1 OTC. When adsorption and photocatalytic degradation were arranged in tandem, the system removed 99% of OTC with a dose of 2.83mg H2O2/mg OTC. The thermo-kinetic interpretation of the adsorption measurements was well described by Sip´s isotherm and pseudo-second kinetic models, which along with the heat of adsorption (−104.8kJmol−1) suggest a chemical interaction between the OTC and MIL-53(Al)@Rice Husk hybrid active centres. The MIL-53(Al)@RH hybrid demonstrated a remarkable stability with an OTC removal above 90% after 10 operational cycles. Moreover, pyrolysis of OTC-saturated hybrid led to a carbonaceous structure which demonstrated an outstanding OTC adsorption capacity (221mgg−1 OTC). The results demonstrate that the MIL-53(Al)@RH hybrid presents a significant prospect for combined adsorption-photocatalytic treatment of water bodies contaminated with antibiotics.

Synthesis of a novel bismuth molybdite/iron oxide thin film for oxytetracycline degradation in a photoelectrocatalytic system

In this study, heterostructures based on Bismuth molybdite/iron oxide (Bi2MoO6/Fe2O3) thin films were fabricated by a dip-coating technique using precursor solutions. The heterostructures were deposited on fluorine-doped tin oxide glass substrates. From a detailed characterization using X-ray diffraction and X-ray photoelectron spectroscopy, the formation of the orthorhombic phase for Bi2MoO6 and the co-existence of hematite and maghemite in Fe2O3 was demonstrated. Meanwhile, the field emission scanning electron microscopy cross-section images confirm the formation of well-defined Bi2MoO6 film under the Fe2O3 deposition. The optical band gap energies for the heterostructure obtained were estimated from the diffuse reflectance spectra and ranged from 2.3 to 3.5 eV. Photoluminescence analysis revealed an improved separation and faster transfer of photogenerated electrons and holes for the Bi2MoO6/Fe2O3 (Het) film. The best oxytetracycline (OTC) removal percentage through photoelectrocatalytic treatment was 96.85% using the Het. Besides, were carried out the variation of parameters which affect the OTC photoelectrocatalytic degradation as pH, potential applied, and scavenger assay. The 1O2 was the oxidant predominate, which attack the OTC ring to initiate and accelerate the degradation process. Based on the analysis of degradation intermediates and characteristics of Bi2MoO6/Fe2O3, possible degradation pathways and mechanisms of OTC were displayed. An enhancement of oxytetracycline degradation efficiency of Het fabricated compared to pristine oxides was achieved mainly due to avoid the charge recombination of photogenerated electron-hole pairs provided by Direct Z-scheme heterostructure. Finally, the Het fabricated represents a promising material for efficient and sustainable pharmaceutical removal applications.

A smartphone-integrated bimetallic ratiometric fluorescent probe for specific visual detection of tetracycline antibiotics in food samples and latent fingerprinting

Designing and preparing highly sensitive and accurate fluorescent chemosensors for monitoring tetracycline antibiotics remains a challenge. Herein, a fluorescent chemosensor based on lanthanide metal-organic frameworks (Ln-MOFs) is proposed to realize high-precision monitoring by adjusting the ratio of lanthanide ions. Ln-MOFs with good aqueous stability were prepared by a solvothermal method using Eu3+, Tb3+ and the ligand 4,4′,4″-s-triazine-2,4,6-triyltribenzoic acid (H3TATB) in DMF/NMP/H2O. The Ln-MOFs could recognize oxytetracycline (OTC) and doxycycline (DOX), and the detection limits of OTC and DOX were as low as 8.6 and 4.8 nM, respectively. In particular, Eu(1.4 μM)-Tb-MOF sensors were used for visual detection of OTC and DOX in combination with smartphones with detection lines as low as 9.8 nM and 14.2 nM, respectively. Meanwhile, Eu-MOF, Tb-MOF and Eu(1.4 μM)-Tb-MOF can be used for latent fingerprint (LFP) visualization, demonstrating their potential applications in the field of criminal case investigation. The developed probes were successfully applied to determining OTC and DOX in milk, beef and pork with recoveries ranging from 92.0 % to 109.63 % and relative standard deviations (RSDs) ranging from 1.83 % to 4.56 %. Eu(1.4 μM)-Tb-MOF is believed to utilize its lanthanide metal ion coordination and photoinduced electron transfer (PET) mechanism to achieve highly selective and accurate OTC and DOX detection, which is supported by experimental and density functional theory (DFT) calculations.

Effects of water matrices on the removal of oxytetracycline antibiotic and total organic carbon (TOC) using four different oxidation processes

Antibiotic compounds are actively discharged into aquatic environments through wastewater, potentially contributing to the emergence of drug-resistant bacteria and associated health issues. Oxidation processes (OPs), including advanced oxidation processes (AOPs), have gained attention as promising methods for removing antibiotics from wastewater. In this study, we comprehensively compared the efficiencies of removing oxytetracycline (OTC) and total organic carbon (TOC) by four OPs. These processes include three AOPs: the ozone/hydrogen peroxide process (O3/H2O2), photo-Fenton reaction (Fe/H2O2/UV), and Fenton reaction (Fe/H2O2), and ozonation (O3) as a conventional OP. To evaluate the effects of different water matrices, the degradation experiments were conducted using ultrapure water and actual wastewater. All four OPs achieved over 99% OTC degradation within 15 minutes of the experiment. The photo-Fenton reaction exhibited the highest TOC removal rates (66% for ultrapure water and 74% for actual wastewater) after 210 minutes. Conversely, ozonation resulted in the lowest TOC removal rates (7% for ultrapure water and 10% for actual wastewater). Therefore, this study suggests that the photo-Fenton reaction may be most suitable for degrading OTC and removing TOC from wastewater.

Iron mediated n → π* electron transitions and mid-gap states formation in CN under low-temperature secondary calcination enhances photodegradation of organic pollutants

Iron modified carbon nitride (CN) materials have attracted widespread attention from researchers in different application fields. In this paper, single atom iron anchored CN (FeCN) with mid-gap states and n → π* electron transition was synthesized through low temperature secondary calcination. The mid-gap states introduce surface states capable of trapping photogenerated electrons, enabling FeCN to absorb photons with energies lower than its intrinsic optical bandgap. 10%FeCN also exhibits distinct optical absorption above 490 nm derived from the n → π* electron transition, which expand the visible light response range of photocatalysts and enhance electron transport ability. Additionally, the Fe-Nx site enhances the separation and transmission efficiency of photoexcited charges. The prepared 10%FeCN exhibits extremely high photocatalysis and photo-Fenton activity. Mercaptobenzothiazole (MBT) degradation rate of 10%FeCN is 3.47 times higher than CN, achieving a mineralization rate of 86.7% in 100 min. Additionally, the oxytetracycline hydrochloride (OTC) degradation rate of 10%FeCN in photo-Fenton reaction is 11.9 times higher than CN. After five cycles, this catalyst still has good reactivity, indicating its good stability.

Effective removal of tetracycline antibiotics from water by in-situ nitrogen-doped porous biochar derived from waste antibiotic fermentation residues

This study explored the utilization of waste oxytetracycline fermentation residue (OFR), abundant in nitrogen and organic matter, to prepare in-situ nitrogen-doped porous biochar (activated OFR derived biochar, AOBC) through a coupled pyrolysis process, and investigated the removal of tetracycline antibiotics (TCs) from water with the prepared AOBCs. The physicochemical characterization results showed the characterizations of abundant nitrogen functional groups, high specific surface area (1960.38 m2/g), and the high microporosity (61.6%) for AOBCs. At 25 ℃, the maximum adsorption capacity calculated by Langmuir model of AOBC-3-600 for tetracycline hydrochloride (TC), chlortetracycline hydrochloride (CTC), oxytetracycline hydrochloride (OTC), and doxycycline hydrochloride (DOC) reached 473.00, 293.28, 220.61, and 282.72mg/g, respectively. The superior fit of the pseudo-second-order and Langmuir models indicated that the adsorption mechanism involved both the physical effect (pore filling) and chemical interactions (electrostatic attraction, hydrogen bonding, π-π interaction, and Lewis acid-base interaction). Environmental risk assessments substantiated the absence of residual oxytetracycline and antibiotic resistance genes in the prepared biochar, indicating its application safety. This research provides a sustainable route to simultaneously treat the antibiotic contamination in water and rationally utilize antibiotic fermentation residues.

Uncovering the mechanisms of ethanol stimulation on magnetite-enhanced anaerobic process treating oxytetracycline contained wastewater

Magnetite has been proved to facilitate direct interspecies electron transfer (DIET)-based syntrophys and might alleviate inhibitory effects of antibiotics in anaerobic digestion (AD), while feeding ethanol was an effective approach to enrich the DIET partners. However, most of the existing studies were conducted at fixed ethanol concentration, few attentions were paid on the effects of differential ethanol proportion on AD, the underlying roles and mechanisms of ethanol stimulation remains unclear. This study systematically investigated the impact of ethanol stimulation on anaerobic processes treating oxytetracycline (OTC)-contaminated wastewater at varying proportions (20%, 50%, and 80%, based on equivalent COD value). In the presence of magnetite, ethanol stimulation promoted the methane production from 244.9 mL/g COD to a maximum 434.2 mL/g COD, with the most pronounced enhancement observed at high ethanol proportions. In particular, the average methane production obtained at 50% and 80% ethanol was 328.5 and 297.7 mL/g COD, respectively, whereas the enhancement of 20% ethanol stimulation was relatively limited. Concurrently, more stable COD removal and OTC reduction was noted in the existence of both magnetite and high ethanol proportions. Microbial analysis revealed the pivotal roles of Methanosaeta, alongside the predominance of Methanobacterium, in regulating COD conversion and driving methanogenesis through the CO2 reduction pathway. Notably, high ethanol proportions fostered the enrichment of exoelectrogens (Geobacter, Desulfovibrio) in the magnetite-amended system, accompanied by the up-regulation of genes involved in organic metabolism pathways. Further investigation of functional genes highlighted the prevalence of pilA enrichment in the magnetite-amended system at low ethanol proportions, whereas omcS became more abundant at high ethanol proportions.

Efficient photocatalytic degradation of tetracycline and its derivatives by green recyclable PAN/Bi2WO6/Cu2O nanofiber membrane

The use of tetracycline antibiotics in industry, healthcare, animal husbandry, agriculture, and aquaculture has resulted in excessive concentrations in a variety of aquatic environments. In this work, PAN/Bi2WO6/Cu2O nanofibrous membranes (PBC ENMs) with photocatalytic degradation performance were successfully prepared using electrostatic spinning technique, and the morphology of catalysts and PBC ENMs were characterised by SEM, BET and UV–Vis. The results demonstrated that the prepared nanofibrous membranes could achieve 97.05 % photocatalytic degradation of TC under visible light, and the degradation efficiencies of its derivatives, chlortetracycline (CTC) and oxytetracycline (OTC), reached 90.87 % and 85.12 %, respectively. Free radical trapping experiments and mechanistic analyses showed that·O2– is the main active factor in the degradation process. The highest degradation rate of 97.05 % was achieved at initial pH = 7.2.PBC ENMs adsorbed above 87.5 % after six cycles of the experiment. The highest degradation rate of 97.05 % was achieved at initial pH = 7.2 PBC ENMs adsorbed above 87.5 % after six cycles of the experiment. Based on the above advantages, the preparation process of PBC ENMs is simple, low-cost and has good catalytic effect, which provides a simple and efficient treatment means for the treatment of TC wastewater and has a broad application prospect.

Efficient production of singlet oxygen via dioxygen activation on Cu0 decorated MoS2 facilitates the elimination of oxytetracycline

Molecular oxygen (O2), a green oxidant, is applied in advanced oxidation processes, which represents one of the current focal points in water treatment research. However, achieving efficient and economical activation of O2 remains a formidable challenge because of its spin-restricted nature. Herein, zero-valent copper (Cu0) modified molybdenum disulfide (MoS2) materials were applied as O2 activators to degrade organic pollutants. The results showed that Cu0-MoS2 could significantly enhance the activation of O2 and thus accelerate the removal of oxytetracycline (OTC). Notably, 90.0 % of OTC was eliminated within 20 min in the Cu0-F-MoS2 (Cu0-Flower-MoS2) /air system. Quenching experiments, XPS spectra, and DFT calculations confirmed •O2− and 1O2 were pivotal reactive species, with both Mo and Cu playing essential roles. Specially, O2 was activated by Cu0/Cu+ to generate •O2−, then •O2− was oxidized by Mo6+ of MoS2 into 1O2. This research offers an eco-friendly approach for eliminating organic substances by activating O2.

Removal of aqueous oxytetracycline using copper-loaded biochar-activated peroxodisulfate: Synergistic mechanism of adsorption and nonradical 1O2

Antibiotic contamination from livestock and poultry farming wastewater has caused substantial adverse effects on the environment and humans. Therefore, in this study, bifunctional adsorption and synergistic degradation of Cu and N codoped biochar (Cu-N/BC) were utilized to efficiently promote the activation of peroxodisulfate (PDS) for removing oxytetracycline (OTC). Cu-N/BC exhibited a high adsorption affinity toward OTC. The adsorption of OTC (50 mg/L) by 0.4 g/L catalyst could reach 36.2 mg/g in 30 min, and the removal of OTC reached 97.24 % in 90 min after adding 0.5 mM PDS. Preadsorption experiments demonstrated that the OTC enriched on the Cu-N/BC surface facilitated the subsequent degradation reaction，its reaction rate constant increases from 0.026 to 0.037. Low-valent copper (Cu0/Cu+), pyridine N, and oxygen-containing functional groups (CO) were the main active sites of Cu-N/BC, and the main contribution toward OTC degradation was from the nonradical pathway of singlet oxygen. Furthermore, potential degradation pathways were revealed, and the intermediates in the OTC degradation process were identified. Cu-N/BC exhibited stable performance, a wide pH application range, and great potential for practical application. This study offers a new concept for designing a bifunctional carbon-based material to remove antibiotics from wastewater.

Determination of Tetracycline Group Antibiotics Residues in the Tigris River and Agricultural Lands Fed by Tigris River and Reduction of Unconscious Use of Antibiotics

The recent increase in environmental pollutants is contaminating important natural resources and causing irreversible damage. Due to the limitations of traditional treatment techniques, studies on the problem of micro pollutant contamination of water resources have increased significantly. Antibiotics used in medicine and veterinary medicine cause significant pollution of water resources as residues of these contaminants remain unchanged in the aqueous environment. This has recently been recognised as a global environmental health threat. The ecosystem is vulnerable to residues of these contaminants from agriculture and aquaculture. In this study, the presence of tetracycline group antibiotics, the most commonly used in veterinary medicine, was determined in the Tigris river. This is the first study to date in which antibiotics from the tetracycline group have been identified in the Tigris river. Water samples were taken from 16 different points (80 samples) along the river. Sampling points were grouped as abattoirs, livestock markets, farmland, cafes and bridges near settlements. The samples were analysed for the presence of tetracycline (TC), oxytetracycline (OTC) and chlortetracycline (CTC). With a concentration range of 0.037 to 1.756 ng/L, oxytetracycline was found in 14 of the 16 sites. A concentration of 0.004–0.014 ng/L of tetracycline was found in five samples. Chlortetracycline was found in six samples, with concentrations ranging from 0.015 to 0.097 ng/L. According to the study, the tetracycline family of antibiotics was found in the water samples, and oxytetracycline was present in the highest concentrations in most of them.

Green Synthesis of Boric Acid Modified Bismuth Based Non-Toxic Perovskite Quantum Dots for Highly Sensitive Detection of Oxytetracycline.

In recent years, perovskite quantum dots (PQDs) have successfully attracted widespread attention due to their excellent optical properties. However, the instability and toxicity problems of perovskite quantum dots are the main obstacles limiting their applications. In this work, bismuth-based perovskite quantum dots were synthesized by a ligand-assisted reprecipitation method, based on which a novel boric acid-functionalized bismuth-based non-toxic perovskite quantum dots fluorescent sensor (Cs3Bi2Br9-APBA) that can be stabilized in the ethanol phase was prepared by a boron affinity technique. Based on the covalent binding interaction of Cs3Bi2Br9-APBA with oxytetracycline (OTC), a highly selective and sensitive method for the detection of OTC was developed, which effectively solved the problems of poor stability and toxicity in the application of perovskite quantum dots. Under the optimal conditions, the fluorescence intensity of the synthesized Cs3Bi2Br9-APBA was linear with the concentration range of 0.1 ∼ 18 µM OTC, and the detection limit could reach 0.0802 µM. The fluorescence detection mechanism was explored and analyzed by spectral overlap analysis, suppression efficiency study of observed and corrected fluorescence, and fluorescence lifetime decay curve fitting, the mechanism of OTC detection by Cs3Bi2Br9-APBA was identified as the inner filter effect (IFE). In addition, the sensor successfully realized the quantitative detection of trace OTC in the environment, and our study provides a new idea for the preparation of green perovskite materials with high stability and selectivity.

Selective oxidation of organic pollutants by unactivated and carbonate-activated peroxymonosulfate (PMS): Mechanism, kinetics, and transformation pathway

Although the activation mechanisms of peroxymonosulfate (PMS) by various homogeneous and heterogeneous catalysts have been reported, the chemistry of PMS in catalyst-free systems and its interaction with background oxygenated anions remains poorly understood. In this study, the unactivated PMS and carbonate-activated PMS (CO32–/PMS) systems for removal of various organic pollutant (including oxytetracycline (OTC), metronidazole (MNZ), methylene blue (MB), and acid orange G (OG)) were investigated. The results showed that 74.5 %, 90.21 %, 1.22 %, and 2.25 % of OTC, MB, OG, and MNZ were removed, respectively within 180 min in the unactivated PMS system due to the formation of ·OH and 1O2. 95.88 %, 100 %, 100 %, and 6.09 % of OTC, MB, OG, and MNZ were removed, respectively in the CO32–/PMS system, which is primary due to the generation of 1O2. The removal efficiencies of these four pollutants were significantly improved under alkaline conditions. In addition, the TOC removal rates were 21.88 % for MB and 26.53 % for OTC within 180 min in the CO32–/PMS system. The presence of Cl− and SO42− can greatly enhance the OTC removal efficiency both in the unactivated and CO32–/PMS systems. Through the high performance liquid chromatography-mass spectrometry (HPLC-MS) analysis, OTC degradation products in the unactivated PMS and CO32–/PMS systems were identified, revealing six different reaction mechanisms, including hydroxylation (+16 Da), decarbonylation (−28 Da), demethylation (−14 Da), secondary alcohol oxidation (−2 Da), deamination (−15 Da), and dehydration (−18 Da). This study provides insight into the reaction mechanism of catalyst-free PMS systems and may promote the application of unactivated PMS and CO32–/PMS systems for the remediation of organic contaminated water.

Assessment of sulfamethoxazole and oxytetracycline uptake and transformation in Eisenia fetida earthworms

The scientific community is becoming increasingly concerned about the recent detection of transformation products (TPs) of antimicrobials (AMs) and their presence in the food chain. There are growing concerns about the potential consequences on food safety and the proliferation of antimicrobial resistance. In this work, the transformation process of sulfamethoxazole (SMX) and oxytetracycline (OTC) in soil was thoroughly evaluated. For that purpose, soils were homogeneously contaminated at three concentration levels of SMX and OTC, independently, and samples were analysed after 7 and 14 days by Ultra High-Performance Liquid Chromatography coupled to a triple quadrupole mass spectrometer (UHPLC-MS/MS). The results have demonstrated a remarkable transformation, particularly noteworthy for SMX, as it exhibited an 89 % - 94 % decrease in concentration within the initial 7 days of the experiment. In addition, to assess whether terrestrial organisms would be able to accumulate the AMs, Eisenia fetida (E. fetida) earthworms were exposed to the above-mentioned concentration levels of AMs in soil. Both AMs were accumulated in the organisms after 14 days, but higher bioaccumulation factor values (BCF) were determined for SMX (0.52–17.84) compared to OTC (0.02–0.21) at all tested concentrations. The analyses were extended to search for TPs in earthworms and soils using a suspect screening approach. Concretely, by means of UHPLC-high resolution mass spectrometry (UHPLC-HRMS) three TPs were identified at 2a and 2b of confidence level. To the best of our knowledge, one SMX-TP and one OTC-TP were identified in earthworms and soil, respectively, for the first time in the present work. Earthworms did not experience weight loss or mortality in the presence of these AMs at levels found in the environment, but there was a decrease in riboflavin levels, which is linked to changes in the immune system. This study represents a significant advancement in understanding the impact of AMs in soil and their subsequent entry into the food chain. It also provides valuable insights into the potential effects of AMs and their TPs on organisms.

Fast and Simple Extraction for LCMSMS Analysis of Oxytetracycline Residue in Pork

Pork is very popular as an animal-base protein source of peoples in the Lao PDR. The pig growth promotion, treatment and prevention of diseases frequently relies on the use of antibiotics. In terms of food safety, the analysis of antibiotic residue in pork would be therefore important. Oxytetracycline (OTC) is one of antibiotics used in the pig husbandry. In this study, a fast and simple extraction and analysis method for determining OTC residue in pork was developed. Briefly, 1.0 g of homogenized pork sample in a 50mL-centrifµge tube was extracted with 10 mL of CH3OH: H2O mixture (9:1 ratio) assisted with vortex for 10 min, treated with QuEChERS salt and subjected to centrifugation at 5000 rpm. The methanolic extract (1.5 mL) was then cleaned up with 2mL-dSPE tube (containing MgSO4, PSA, and C18), filtered through syringe filter 0.45 micron and analyzed with ESI-LCMS/MS optimized and operated in MRM positive mode. Calibration was prepared with OTC standard solutions (5-100 ng/g). The analytical method was validated with triplicated recovery tests at a spiked level of 50 ng/g. The results unveiled that the method gave very good recovery of 88.7±3.24%. The limits of detection (LOD) and quantification (LOQ) were achieved with 0.36 ± 0.02 and 1.19 ±0.04 ng/g. In consequence, the developed method would be suitable for OTC determination in pork samples.

Ratiometric fluorescence sensing and discrimination of tetracycline analogs by using coumarin-embedded Eu-MOF nanosensor

As widely used antibiotics, tetracycline residues exist in food and environmental media, which pose certain hidden dangers and negative effects on public health. Therefore, the sensing and discrimination of tetracycline analogs (TCs) have great significance for improving food safety and preventing environmental pollution. Herein, a 7-hydroxycoumarin-3-carboxylic acid-embedded Eu-MOF (HC@Eu-MOF) material was constructed and then developed for the detection of TCs. Upon addition of TCs, the synthesized sensor displays opposite fluorescence changes at two different wavelengths due to the simultaneous presence of the inner filter effect (IFE) and the antenna effect (AE), and achieves a stable ratio signal response within 90 s. In addition, six important tetracycline analogs, including chlortetracycline (CTC), oxytetracycline (OTC), tetracycline (TC), metacycline (MC), doxycycline (DC) and demeclocycline (DMC) can be discriminated with 100 % accuracy through the principal component analysis even in extremely complicated mixtures. Further, a smartphone-assisted portable device was applied for visual sensing of TCs. The as-developed platform possessed the characteristics of simple synthesis, fast response, high sensitivity, and high stability, which further lays a further foundation for the on-site visual detection and discrimination of TCs in real samples.

Effect of sponge city facilities on the exposure characteristics and ecological risks of antibiotics in urban inland lakes: A case study at Fuzhou, China.

Antibiotics are increasingly found in urban lakes, posing significant ecological risks to lake ecosystems. The impact of sponge city facilities on urban flood control is significant; however, their influence on the exposure characteristics and risks associated with antibiotics in urban inland lakes remains unclear. This study investigated the exposure characteristics and evaluated the ecological risks of 15 antibiotics across seven lakes of Fuzhou (as the target of sponge city) in different seasons, in comparison to non-sponge cities. The results revealed that 12 antibiotics were consistently detectable across all lakes, with concentrations ranging from non-detectable (ND) to 20.61ng/L, with sulfamethoxazole (SMX) emerging as the predominant contaminant. Most antibiotics exhibited higher concentrations in the dry season, attributed to environmental conditions, biological mechanisms, and their physicochemical properties. SMX, tetracycline (TTC), oxytetracycline (OTC), and ciprofloxacin (CIP) posed moderate to high ecological risks, with risk quotient (RQ) values of 0.46, 0.14, 0.17, and 0.61, respectively, while the remaining antibiotics presented lower ecological risks in both seasons. Notably, the RQ values for TTC, OTC, and CIP were elevated during the dry season, whereas SMX displayed a higher RQ value in the wet season, indicating an increased ecological risk during the dry months. In comparison to non-sponge cities, sponge cities exhibited significantly lower concentrations of nearly all antibiotics, particularly during the wet season (p ≤ 0.05). Moreover, over 85% of the antibiotics in non-sponge cities were classified as high risk, contrasted with only 55% in sponge cities, underscoring the heightened ecological risks associated with non-sponge urban designs. This study provides critical insights for controlling antibiotic pollution in the lakes of Fuzhou and serves as a valuable reference for maintaining aquatic ecosystem health through the implementation of sponge city infrastructure.

Design and fabrication of acorn-like Janus molecularly imprinted materials for highly specific separation and enrichment of oxytetracycline from restaurant oily wastewater

Molecularly imprinted polymer (MIP) is dedicated to the adsorption of target substances in the aqueous phase, but ignores the adsorption in a more complex environment (oily wastewater). In order to explore the application field of existing MIPs, acorn-like Janus particles were fabricated by photo-initiated seed swelling polymerization. A novel amphiphilic Janus-MIP was prepared with the acorn-like Janus particles as matrix, methacrylic acid, ethylene dimethacrylate and oxytetracycline (OTC) as functional monomers, crosslinking agents and template molecules via surface initiated-atom transfer radical polymerization (SI-ATRP). For comparison, the poly (glycidyl methacrylate-co-ethylene glycol dimethacrylate) (poly (GMA-co-EDMA)) microspheres were also utilized as the matrix to prepare common spherical-MIP. The adsorption capacity of Janus-MIP for OTC was 23.8 mg g−1 in oil-water system, while the adsorption capacity of spherical-MIP for OTC was only 12.6 mg g−1 in the same system. At the same time, through high performance liquid chromatography (HPLC) analysis, Janus-MIP can specifically recognize and adsorb trace OTC in restaurant oily wastewater samples, and the proposed method exhibited a lower limit of detection (LOD, 3 ng mL−1) and a higher OTC recovery rate (94.2 %–98.4 %). This work demonstrated great potential for the detection and control of OTC contamination from real samples in an oil-water mixed environment.