RESUMO
This work presents the development, synthesis, and application of a layered double hydroxide (LDH) coupled to magnetic particles for the removal of antibiotics as tetracyclines (TC´s): tetracycline (TC), chlortetracycline (CT), oxytetracycline (OT), and doxycycline (DT) from milk samples. The LDH synthesis conditions, reaction time (30-90 min), molar ratios Mg2+/Al3+ (7:1-1:7), interlayer anion (NO3-, Cl-, CO32-, and dodecyl sulphate (DS-)) were evaluated. Under synthesis conditions (reaction time of 30 min, Mg2+/Al3+ molar ratio of 7:1, and DS- as interlayer anion), the LDH was coupled in a magnetic solid phase microextraction (MSPµE) methodology. At the optimal extraction conditions (pH 6, 5 min of contact time, 10 mg of adsorbent), a removal percentage of 99.0 % was obtained for each tetracycline. FTIR, TGA, SEM, and adsorption isotherms were employed to characterize the optimal adsorbent. Each experiment was corroborated by large-volume sample stacking capillary electrophoresis (LVSS-CE). The adsorbent was applied directly to positive milk samples (previously tested) for TC´s removal.
Assuntos
Hidróxidos , Leite , Tetraciclinas , Leite/química , Animais , Tetraciclinas/isolamento & purificação , Tetraciclinas/análise , Tetraciclinas/química , Hidróxidos/química , Adsorção , Microextração em Fase Sólida/métodos , Antibacterianos/isolamento & purificação , Antibacterianos/química , Antibacterianos/análise , Dióxido de Silício/químicaRESUMO
Biochar, a sustainable sorbent derived from pyrolyzed biomass, has garnered attention for its efficacy in solid-phase extraction (SPE) of antibiotics, with a particular focus on tetracyclines (TCs). Despite its recognized potential, the intricate separation mechanisms operative in biochar-based SPE systems have not been fully deciphered. This investigation contrasts chlorella biochar against commercial bamboo biochar, harnessing an array of analytical methodologies-microstructure characterization, adsorption thermodynamics, competitive adsorption kinetics, H+ back titration, and selectivity adsorption studies-complemented by a Box-Behnken design for the optimization of chlorella/bamboo-SPE and subsequent application in the analysis of animal-derived foodstuffs. The study unveils that a hybrid sorbent, integrating nitrogen-doped microporous chlorella biochar with mesoporous bamboo biochar in a 95/5 mass ratio, markedly diminishes irreversible adsorption while enhancing selectivity, surpassing the performance of single biochar SPE systems. The elucidated separation mechanisms implicate a partition model, propelled by oxygen-rich functional groups on chlorella biochar and the rapid adsorption kinetics of bamboo biochar, all orchestrated by electrostatic interactions within the mixed biochar framework. Moreover, the synergy of mixed biochar-SPE with high-performance liquid chromatography (HPLC) demonstrates exceptional proficiency in detecting TCs in animal viscera, evidenced by recovery rates spanning 80.80 % to 106.98 % and RSDs ranging from 0.24 % to 14.69 %. In essence, this research not only sheds light on the multifaceted factors influencing SPE efficiency but also propels the use of biochar towards new horizons in environmental monitoring and food safety assurance.
Assuntos
Carvão Vegetal , Chlorella , Extração em Fase Sólida , Tetraciclinas , Carvão Vegetal/química , Extração em Fase Sólida/métodos , Adsorção , Chlorella/química , Tetraciclinas/isolamento & purificação , Tetraciclinas/química , Tetraciclinas/análise , Animais , Cinética , Cromatografia Líquida de Alta Pressão/métodos , Antibacterianos/isolamento & purificação , Antibacterianos/química , TermodinâmicaRESUMO
Novel metal-organic framework MIL-101(Cr)-NH2 functionalised hydrophilic polydopamine-modified Fe3O4 magnetic nanoparticles (Fe3O4@PDA@MIL-101(Cr)-NH2) were synthesised and used as magnetic solid-phase extraction (MSPE) adsorbents for extracting tetracyclines (TCs) from milk samples. The integrated Fe3O4@PDA@MIL-101(Cr)-NH2 exhibited convenient magnetic separation and exceptional multi-target binding capabilities. Furthermore, the PDA coating significantly enhanced the hydrophilicity and extraction efficiency of the material, thereby facilitating the extraction of trace TCs. Various factors affecting MSPE, such as adsorbent dosage, extraction time, pH value, and desorption conditions, were optimised. The developed MSPE method coupled with high-performance liquid chromatography demonstrated good linearity (R2 ≥ 0.9989), acceptable accuracy (82.2%-106.1%), good repeatability (intra-day precision of 0.8%-4.7% and inter-day precision of 1.1%-4.5%), low limits of detection (2.18-6.25 µg L-1), and low limits of quantification (6.54-18.75 µg L-1) in TCs detection. The approach was successfully used for the quantification of trace TCs in real milk samples.
Assuntos
Nanopartículas de Magnetita , Estruturas Metalorgânicas , Leite , Extração em Fase Sólida , Tetraciclinas , Leite/química , Extração em Fase Sólida/métodos , Extração em Fase Sólida/instrumentação , Estruturas Metalorgânicas/química , Tetraciclinas/isolamento & purificação , Tetraciclinas/química , Tetraciclinas/análise , Animais , Nanopartículas de Magnetita/química , Interações Hidrofóbicas e Hidrofílicas , Cromatografia Líquida de Alta Pressão , Adsorção , Contaminação de Alimentos/análiseRESUMO
Three-dimensional sponge-architecture covalent organic frameworks (COFs)-aerogel was successfully designed and synthesized via a freeze-drying template approach, and utilized as an efficient sorbent in solid-phase extraction (SPE). A method for selective enrichment of pharmaceutical contaminants including tetracycline, chlortetracycline, methacycline and oxytetracycline in the environment and food samples was proposed by combining with high performance liquid chromatography (HPLC). To understand the adsorption mechanism, selectivity test and molecular dynamics (MD) simulated calculation were both carried out. The experimental and in-silico results demonstrated that the COFs-aerogel possessed high selectivity for contaminants with H bond acceptors/donors and good efficiency with maximum adsorption capacity up to 294.1 mg/g. The SPE-based HPLC method worked well in the range of 8-1000 ng/mL, with the need of little dose of adsorbent and sample volume while no need of spectrometer, outgoing the reported adsorbents. Under the optimized conditions, the intra-day and inter-day relative standard deviations (RSD) of repeatability were within 2.78-6.29 % and 2.44-8.42 % (n = 5). The results meet the current detection requirement for practical applications, and could be extended for further design of promising adsorbents.
Assuntos
Antibacterianos , Estruturas Metalorgânicas , Extração em Fase Sólida , Tetraciclinas , Adsorção , Extração em Fase Sólida/métodos , Estruturas Metalorgânicas/química , Antibacterianos/química , Antibacterianos/análise , Tetraciclinas/análise , Tetraciclinas/química , Tetraciclinas/isolamento & purificação , Cromatografia Líquida de Alta Pressão/métodos , Simulação de Dinâmica Molecular , Géis/química , Tetraciclina/análise , Tetraciclina/química , Tetraciclina/isolamento & purificação , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química , Contaminação de Alimentos/análiseRESUMO
Pollution by tetracyclines antibiotics has a great potential risk on human and animal health even at trace levels. Copper nanoparticles immobilized-ß-cyclodextrin functionalized reduced graphene oxide (Cu/ß-CD/rGO) were successfully prepared as an efficient extractor of tetracycline (TC), oxytetracycline (OTC) and doxycycline (DC) antibiotics from different environmental water samples. Tetracyclines (TCs) are strongly deposited in the matrix of Cu/ß-CD/rGO nanocomposite via surface complexation with the Cu-nanoparticles besides the formation of inclusion complexes with ß-cyclodextrin and π-π interaction of reduced graphene oxide. The novel nanocomposite was characterized by HRSEM, TEM, TGA, FT-IR, XPS, and XRD. The optimization of variables such as the pH, contact time, ionic strength and TC concentration were successfully analyzed. The maximum adsorption capacity (qm) of Cu/ß-CD/rGO calculated from the Langmuir isotherm was 403.2 mg.g-1 for TC, 476.2 mg.g-1 for OTC and 434.8 mg.g-1 for DC at 298 K. The removal efficiency was decreased by 3.7% after five adsorption-desorption cycles. The Cu/ß-CD/rGO nanocomposite was applied for removing TCs from tap water and the Nile River water samples. The novel nanocomposite demonstrated fast and highly efficient removing performance for different TCs with low levels and large sample volume.
Assuntos
Cobre/química , Grafite/química , Nanocompostos/química , Tetraciclinas/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , beta-Ciclodextrinas/química , Adsorção , Animais , Antibacterianos/isolamento & purificação , Biodegradação Ambiental , Doxiciclina/isolamento & purificação , Humanos , Nanopartículas/química , Oxitetraciclina/isolamento & purificação , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Tetraciclina/isolamento & purificação , Água/química , Purificação da Água/métodosRESUMO
Four new thymol-based ternary deep eutectic solvents were prepared and evaluated as the extractive phase in air-bubbles assisted dispersive liquid-liquid microextraction for extraction of tetracycline, doxycycline, and oxytetracycline from the water before high-performance liquid chromatography. The maximum extraction efficiencies were obtained using 400 µL of [choline chloride]:[thymol]:[nonanoic acid] in the molar ratio of 1:2:2 at pH = 5. The solvent was characterized by FTIR and NMR spectroscopy. The hydrophobicity of the deep eutectic solvent and its effect on the pH of water samples after mixing was also studied. Besides, the extraction efficiency of the ternary deep eutectic solvent was compared with that of two binary thymol-based deep eutectic solvents, including [choline chloride]:[thymol] and [thymol]:[nonanoic acid] at the same conditions. Under optimal conditions, limits of detection and quantification were 1.2-8.0 and 3.8-26.6 µg/L, respectively. The linear ranges were 18.2-500 µg/L for oxytetracycline, 26.6-500 µg/L for tetracycline, and 3.8-500 µg/L for doxycycline with the determination coefficients > 0.9912. Intra- and inter-day relative standard deviations were 1.2-3.8 and 7.7-11.2%, respectively. The developed method was applied to the analysis of tetracyclines in unspiked and spiked environmental water samples, and the obtained recoveries were 74.5-95.4% with relative standard deviations of 1.2-4.0%.
Assuntos
Solventes Eutéticos Profundos/química , Microextração em Fase Líquida/métodos , Tetraciclinas/análise , Timol/química , Cromatografia Líquida de Alta Pressão , Resíduos de Drogas/análise , Resíduos de Drogas/química , Resíduos de Drogas/isolamento & purificação , Interações Hidrofóbicas e Hidrofílicas , Limite de Detecção , Modelos Lineares , Reprodutibilidade dos Testes , Tetraciclinas/química , Tetraciclinas/isolamento & purificação , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificaçãoRESUMO
Metal-organic frameworks (MOFs), a sort of dispersive solid-phase extraction (d-SPE) material, has shown considerable prospects in the pretreatment of food, biological and other complex samples. Herein, we developed a method for compounding MOFs for d-SPE and trace determination of tetracyclines (TCs) in honey. When the compounding ratio of MIL-101 (Cr), MIL-100 (Fe) and MIL-53 (Al) was 7:1:2, adsorption-extraction was effective. Followed by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), the limits of detection were 0.073-0.435 ng/g and the limits of quantitation ranged from 0.239 to 1.449 ng/g for oxytetracycline, tetracycline, chlortetracycline and doxycycline. The method was applied to four kinds of honey samples with recoveries from 88.1% to 126.2%. The compounding of MOFs provides a strategy for purification and multi-target extraction from complex food matrices by d-SPE.
Assuntos
Mel/análise , Estruturas Metalorgânicas/química , Extração em Fase Sólida/métodos , Tetraciclinas/análise , Adsorção , Antibacterianos/análise , Antibacterianos/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Concentração de Íons de Hidrogênio , Espectrometria de Massas em Tandem , Tetraciclinas/isolamento & purificaçãoRESUMO
In this study, a new floating dispersive solid phase extraction method based on deep eutectic solvents has been developed in a home-made extraction device for the extraction of four tetracycline antibiotics from milk samples. In this approach, the sorbent (activated carbon) was dispersed in whole parts of solution with the aid of air stream and floated on top of the solution with the aid of the surfactant (lauryl betaine) and air bubbles. After collection of the sorbent, the adsorbed analytes were eluted with tetrabutyl ammonium chloride-propionic acid deep eutectic solvent under sonication. In this method, there was no need of organic dispersive and extraction solvents and the used sorbent was collected on top of the solution and collected without centrifugation. The validation parameters showed that low limits of detection (0.1-0.3 µg/kg) and quantification (0.6-1.0 µg/kg), acceptable enrichment factors (52-60), efficient extraction recoveries (80-91%), and satisfactory relative standard deviations (≤9.8%) were obtained. Eventually, the method was successfully applied on different milk samples and tetracycline was determined in them.
Assuntos
Antibacterianos/isolamento & purificação , Resíduos de Drogas/isolamento & purificação , Leite/química , Extração em Fase Sólida/métodos , Tetraciclinas/isolamento & purificação , Adsorção , Animais , Antibacterianos/análise , Bovinos , Resíduos de Drogas/análise , Contaminação de Alimentos/análise , Limite de Detecção , Extração em Fase Sólida/instrumentação , Solventes , Tensoativos/química , Tetraciclinas/químicaRESUMO
BACKGROUND: Tetracycline antibiotics are employed for human and animal health and for speeding up growth rates. However, their presence in food products and environmental waters has been a concern for some years. Therefore, a variety of sample preparation methods have been developed for the analysis of tetracycline residues in these matrices. RESULTS: An electrochemically controlled solid phase microextraction based on a modified copper electrode with polyaniline/graphene oxide (PANI/GO) conductive nanocomposite was developed for the extraction of oxytetracycline, tetracycline and doxycycline before high-performance liquid chromatography-UV analysis. PANI/GO was synthesized by in situ chemical oxidative polymerization, characterized by scanning electron microscopy and Fourier-transform infrared spectroscopy, and bound on the electrode using high purity conductive double-sided adhesive carbon glue. The significant factors affecting the performance of microextraction were investigated and optimized. Under the optimized conditions [sample, 15 mL; sorbent, 10 mg; pH, 3.0; electroextraction voltage, -0.9 V; electroextraction time, 20 min; eluent (MeOH/NH3 ), 500 µL; and desorption time, 5 min], the limits of detection for target analytes were in the ranges 0.32-1.01 and 2.42-7.59 µg L-1 in water and milk samples, respectively. The linear ranges were 1.06-750 µg L-1 for water and 8.05-750 µg L-1 for milk samples. The intra-day and inter-day precisions were 2.32-3.80 and 3.29-4.25, respectively. The method was applied to the determination of analytes in milk and water samples with different fat contents, and the recoveries were obtained in the range 71-104%. CONCLUSION: The developed electro-microextraction method provides a facile, rapid, cost-effective, sensitive and efficient promising procedure for the extraction of antibiotics in complex matrices. © 2020 Society of Chemical Industry.
Assuntos
Antibacterianos/isolamento & purificação , Leite/química , Microextração em Fase Sólida/métodos , Tetraciclinas/isolamento & purificação , Poluentes da Água/isolamento & purificação , Compostos de Anilina/química , Animais , Antibacterianos/análise , Bovinos , Cromatografia Líquida de Alta Pressão , Condutividade Elétrica , Contaminação de Alimentos , Grafite/química , Limite de Detecção , Nanocompostos/química , Polímeros/química , Microextração em Fase Sólida/instrumentação , Tetraciclinas/análise , Poluentes da Água/análiseRESUMO
Tetracycline residues have frequently been detected in multi-environmental media, and it could induce antibiotic resistance genes (ARGs) in microorganisms, which has attracted great attention. Where biodegradation processes may be a promising strategy to remove tetracycline. Thus, this study mainly considers: (i) the degradation of tetracycline by microorganisms including single microorganisms and microbial flora; (ii) the elimination of tetracycline during biochemical treatment processes and advanced treatment systems in wastewater treatment plants (WWTPs) and constructed wetlands (CWs); (iii) the degradation of tetracycline by biological coupling processes; (iv) the confusion and problem of tetracycline biodegradation. Furthermore, the characteristics and comparison of tetracycline biodegradation have been discussed in detail. Additionally, future research directions are suggested to reduce tetracycline in the aquatic environment, especially tetracycline biodegradation and the nitrogen conversion process. Highlights Degradation of tetracycline by pure culture strains and microflora was significant. Degradation of tetracycline by biochemical treatment process was summarized. Advanced treatment process in CWs could eliminate tetracycline. Future research directions on biodegradation of tetracycline are proposed.
Assuntos
Bactérias/metabolismo , Biodegradação Ambiental , Fungos/metabolismo , Tetraciclinas , Poluentes Químicos da Água , Reatores Biológicos/microbiologia , Tetraciclinas/química , Tetraciclinas/isolamento & purificação , Tetraciclinas/metabolismo , Eliminação de Resíduos Líquidos , Águas Residuárias/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação , Poluentes Químicos da Água/metabolismo , Áreas AlagadasRESUMO
In the current study, a novel covalent organic frameworks COF-SCU1 incorporated electrospun nanofibers (PAN@COF-SCU1 nanofibers) was fabricated via a facile electrospinning method and utilized as adsorbent in pipette tip solid-phase extraction (PT-SPE) of tetracycline antibiotics (TCs) from foods. The prepared PAN@COF-SCU1 nanofibers possessed both of the unique characteristics of electrospun nanofibers and COFS-CU1, and thus improving the adsorption capacity of the electrospun nanofibers and preventing the problems of leakage and high pressure caused by directly using the nanosize COFs as adsorbent in PT-SPE. The experiments affected the adsorption and desorption efficiencies, such as the loading ratios of COFS-CU1 in nanofibers, the amount of nanofibers, the matrix pH and desorption solvent, were studied in detail. Eventually, a new pipette tip solid-phase extraction-high performance liquid chromatography (PT-SPE/HPLC) method was proposed for the analysis of three TCs from food. Satisfied linearity for TCs was obtained in the range of 4-70 ng mL-1. The limits of detection and quantification were ranged from 0.6 to 3 ng mL-1 and from 2 to 10 ng mL-1, respectively. The interday and intraday precisions (RSD) were all lower than 9%. The proposed PT-SPE/HPLC method was used to determine TCs residues in grass carp and duck samples for the first time. The results could not only explore the availability of PT-SPE in the extraction of TCs in food samples, but also broadened the potential applications of COFs in sample preparation.
Assuntos
Carpas , Patos , Análise de Alimentos , Estruturas Metalorgânicas , Nanofibras , Extração em Fase Sólida , Tetraciclinas , Adsorção , Animais , Antibacterianos/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Análise de Alimentos/métodos , Estruturas Metalorgânicas/síntese química , Nanofibras/química , Tetraciclinas/isolamento & purificaçãoRESUMO
Biocompatible magnetic molecularly imprinted polymers (BMMIPs) were prepared with Zein for the first time, and were used to enrich tetracycline compounds selectively. Innovative combination of BMMIPs and electrochemistry to obtain lower detection line to satisfy industrial detection demands. Using Zein as the crosslinking agent, the polymers were synthesized on the surface of Fe3O4 particles. The scanning electron microscope, transmission electron microscope and X-ray diffraction technologies were used to characterize BMMIPs. Through optimization, BMMIPs attained large adsorption capacity (236.40 mg/g) with fast kinetics (40 min) and followed the Langmuir isotherm and pseudo-second-order kinetic models. BMMIPs had good recognition ability, the selective factors of oxytetracycline, chlortetracycline, doxycycline were 4.78, 4.23, and 3.39, respectively. Excellent linearity was attained in the range of 0.025-500 µg/mL, with low detection limits and low quantitation limits of 0.025 and 0.083 µg/mL. According to our exploring, BMMIPs was ideal materials for enrichment of tetracycline in complex biological samples.
Assuntos
Materiais Biocompatíveis/química , Contaminação de Alimentos/análise , Leite/química , Impressão Molecular/métodos , Tetraciclinas/análise , Adsorção , Animais , Antibacterianos/análise , Antibacterianos/química , Antibacterianos/isolamento & purificação , Técnicas Eletroquímicas , Análise de Alimentos/métodos , Limite de Detecção , Fenômenos Magnéticos , Nanopartículas de Magnetita/química , Polímeros/química , Tetraciclina/análise , Tetraciclina/química , Tetraciclina/isolamento & purificação , Tetraciclinas/química , Tetraciclinas/isolamento & purificação , Difração de Raios X , Zeína/químicaRESUMO
A procedure for separation and preconcentration of tetracyclines from human serum samples involving magnetic dispersive micro-solid phase extraction was proposed. The extraction efficiency of different tetracyclines was improved with the use of the surfactant coated Fe3O4 magnetic nanoparticles. Sorption mechanism was presented, and the potential use of magnetic Fe3O4 nanoparticles coated with different surfactants for tetracyclines adsorption was demonstrated for the first time. The procedure involved nanoparticle floating in a liquid sample phase for analyte extraction followed by elution and determination by high performance liquid chromatography with diode array detection. Influence of the main involved parameters was studied, the system was dimensioned accordingly. The analytical curves were linear in the ranges of 0.25-10 mg L-1 for tetracycline and 0.10-10 mg L-1 for oxytetracycline or doxycycline. Limits of detection were estimated (IUPAC, 3 concept) as 0.08 mg L-1 for tetracycline, and 0.03 mg L-1 for oxytetracycline or doxycycline. The proposed procedure proved to be fast (10 min), simple (two stages), inexpensive (10 mg of nanoparticles) and was applied to human serum samples. Unlike previously synthesized nanoparticles for tetracyclines separation, the surfactant-coated Fe3O4 nanoparticles can be easily prepared with widely available and low-cost reagents. Moreover, elution of the analytes was accomplished in absence of organic solvents by an aqueous chelating agent solution.
Assuntos
Compostos Férricos/química , Nanopartículas de Magnetita/química , Microextração em Fase Sólida , Tensoativos/química , Tetraciclinas/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Compostos Férricos/síntese química , Humanos , Fenômenos Magnéticos , Tamanho da Partícula , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Tetraciclinas/sangue , Tetraciclinas/químicaRESUMO
The present work reported a novel hydrophilic and selective solid-phase microextraction fiber by improved multiple co-polymerization method immobilization of tetracycline molecularly imprinted polymer on a stainless steel wire and directly coupled with high-performance liquid chromatography for sensitive determination of trace tetracyclines residues in animal derived foods. The developed molecularly imprinted polymer coated solid-phase microextraction fibers were characterized through scanning electron microscopy, Fourier transfer infrared spectroscopy, thermogravimetric analysis, and adsorption experiments, the fiber with cross-linked and porous structure was observed and high thermal and chemical stability. The maximum adsorption capacity of this fiber with good selectivity reached 2.35 µg/mg in aqueous matrices, and showed good repeatability (relative standard deviation ≤ 6.6%, n = 5) and satisfying reproducibility between fiber to fiber (relative standard deviation ≤ 7.8%, n = 5). Under the optimized solid-phase microextraction conditions, satisfactory linearity (5-1000 µg/L) and detection limits (0.38-0.72 µg/kg, S/N = 3) for all the tetracyclines were obtained. The practicality of this method was proved by adding tetracycline, oxytetracycline at three levels to milk, chicken, and fish samples with good recoveries of 77.3-104.4%.
Assuntos
Ração Animal/análise , Análise de Alimentos , Leite/química , Impressão Molecular , Microextração em Fase Sólida , Tetraciclinas/isolamento & purificação , Animais , Bovinos , Galinhas , Cromatografia Líquida de Alta Pressão , Peixes , Interações Hidrofóbicas e Hidrofílicas , Estrutura Molecular , Polímeros/síntese química , Polímeros/química , Porosidade , Aço Inoxidável/química , Tetraciclinas/químicaRESUMO
A novel approach for stir membrane liquid phase microextraction of tetracyclines from biological fluids was developed. The microextraction procedure assumed in situ formation of microdroplets of a hydrophobic medium-chain fatty acid (extraction solvent) from homogeneous sample solution containing water-soluble medium-chain fatty acid salt by acidification and simultaneous analytes extraction and organic phase separation into pores of stir membrane disk. Obtained large surface area between the extraction solvent and aqueous phase and high porosity of the membrane provided fast extraction and phase separation (extraction time - 5 min) and reducing extraction solvent volume to the order of several µL. The developed approach was applied for the HPLC-UV determination of tetracycline, oxytetracycline and chlortetracycline in biological fluids samples. The calibration graphs were linear over the concentration ranges of 0.1-100 mg L-1 for oxytetracycline, tetracycline and chlortetracycline. Regression coefficients were in the range from 0.994 to 0.998. The LOD values, calculated from the blank tests based on 3σ, were 30 µg L-1 for tetracycline, oxytetracycline and chlortetracycline. The RSD values expressing intra-day and inter-day repeatability were lower than 5% and 8%, respectively.
Assuntos
Técnicas de Química Analítica/métodos , Cromatografia Líquida de Alta Pressão , Microextração em Fase Líquida , Solventes/química , Tetraciclinas/isolamento & purificação , Interações Hidrofóbicas e Hidrofílicas , Água/análiseRESUMO
A novel restricted access media-magnetic molecularly imprinted polymers (RAM-MMIPs) was prepared as magnetic-solid phase extraction (M-SPE) material for tetracyclines (TCs). The RAM-MMIPs can not only specifically adsorb target molecules in samples, but also effectively eliminate the interference of protein macromolecules. The protein exclusion rate is 99.4%. Besides, RAM-MMIPs have a uniform imprinted and hydrophilic layer (600â¯nm), rapid binding kinetic (35â¯min), high selectivity and larger adsorption capacity. The M-SPE was coupled with HPLC/UV to extract TCs from untreated milk and egg samples, and several major factors affecting M-SPE efficiency were optimized. Under optimized conditions, the developed method achieved good linearity (R2>0.9989), lower limits of detection (LOD) and higher recoveries of TCs. For milk samples, the LOD is 1.03-1.31⯵g L-1 and the recovery is 86.7% to 98.6% with relative standard deviation (RSD) of 1.4-5.7%. For the egg samples, the LOD, recovery and RSD are 2.21-2.67⯵g L-1, 84.2-96.5% and 1.7-5.9%, respectively. Consequently, this work provides an improved strategy for the selective extraction and detection of target molecules directly from complex samples with proteins.
Assuntos
Antibacterianos/isolamento & purificação , Resíduos de Drogas/isolamento & purificação , Microesferas , Impressão Molecular , Extração em Fase Sólida/métodos , Tetraciclinas/isolamento & purificação , Adsorção , Animais , Cromatografia Líquida de Alta Pressão , Ovos/análise , Interações Hidrofóbicas e Hidrofílicas , Limite de Detecção , Fenômenos Magnéticos , Leite/química , Polímeros/química , Drogas Veterinárias/isolamento & purificaçãoRESUMO
Tetracyclines accumulation in soil environment potentially threatens agroecosystem safety. Interestingly, biochar could clean up organic pollutants, but to what extent biochar affects the removal of tetracyclines is unknown. To investigate it, five types of biochars derived from cow manure (CMB) and other four plant materials were respectively added into soils contaminated with a mixture of tetracycline, oxytetracycline, and chlortetracycline for 60-day incubation in the dark. Three parent tetracyclines and their corresponding intermediates (epitetracycline, anhydrotetracycline, epianhydrotetracycline, epioxytetracycline, epichlortetracycline, and demethylchlortetracycline) were respectively determined and named as TTCs, OTCs and CTCs. Obtained results showed biochar especially CMB could effectively remove the antibiotics (P < 0.05). Compared to control, the removal rate of TTCs, OTCs and CTCs respectively increased by up to 10.86%, 10.29% and 10.12% in CMB-added soil. The increased removal rate of the antibiotics after biochar addition was due to the increasing accessibilities for degrading microorganisms via the elevating electrical conductivity. Moreover, biochar addition might stimulate these microbial activities through the increase of C and N supplement. Our results indicate biochar accelerates the removal of tetracyclines and their intermediates by altering soil properties and thus increasing the antibiotics accessibilities, which provide insights into how biochar accelerates the removal for these antibiotics.
Assuntos
Carvão Vegetal , Poluentes do Solo/isolamento & purificação , Solo/química , Tetraciclinas/isolamento & purificação , Carbono/análise , Condutividade Elétrica , Nitrogênio/análiseRESUMO
Among contaminants of emerging concern in the environment, a growing attention has been given to antibiotics and antibiotic-resistant genes (ARGs) due to the rise in their usage and potential ecotoxicological and public health effect. However, the occurrence of these contaminants in the environment is little investigated in developing countries particularly in sub-Saharan regions. In this study, the occurrence of three groups of antimicrobials including tetracycline, sulfonamides and fluoroquinolone, and their corresponding ARGs were investigated in the sediments of Awash River Basin, Ethiopia. Out of twelve studied compounds, sulfadiazine and enrofloxacin showed the highest and lowest detection frequency, respectively. Polymerase chain reaction (PCR) analysis revealed that tetA and tetB occurred in all the samples. The relative abundance of the resistant genes was in the following order: tetA > tetB > sul2 > sul1. Redundancy analysis result indicated that some sediment characteristics were found to have influence on the distribution sul1-resistant gene.
Assuntos
Antibacterianos/isolamento & purificação , Resistência Microbiana a Medicamentos/genética , Genes Bacterianos , Rios/química , Poluentes Químicos da Água/química , Monitoramento Ambiental , Etiópia , Fluoroquinolonas/isolamento & purificação , Reação em Cadeia da Polimerase , Sulfonamidas/isolamento & purificação , Tetraciclinas/isolamento & purificaçãoRESUMO
The presented study describes the development of reversed-phase liquid chromatography method using a core-shell particle column with a pentafluorophenyl stationary phase for the dissociation constant (pKa) determination of the tetracycline group antibiotics (tetracycline, oxytetracycline, chlortetracycline) and their epimers (4-epitetracycline, 4-epioxytetracycline, 4-epichlortetracycline). The pH values were measured in the acetonitrile (ACN)-water binary mixtures, used as mobile phases, instead of in water and take into account the effect of the activity coefficients. Thermodynamic acid dissociation constant (pKa1) values of studied antibiotics and their epimers were calculated using retention factor (k) at different mobile phase pH values in studied binary mixtures with ACN percentages of 20, 25, 30 and 35% (v/v). Experimental data were analyzed by using an Origin 7.0 program to fit experimental data to the nonlinear expression derived. From calculated pKa1 values, the aqueous pKa values of studied compounds were calculated by different approaches and these values were compared.
Assuntos
Antibacterianos/química , Cromatografia de Fase Reversa/métodos , Tetraciclinas/química , Ácidos/química , Antibacterianos/isolamento & purificação , Concentração de Íons de Hidrogênio , Isomerismo , Cinética , Tetraciclinas/isolamento & purificação , TermodinâmicaRESUMO
Exposure to tetracycline in soil causes microbial mutations. Soil microbial fuel cells (MFCs) can promote the degradation efficiency of contaminants while generating bioelectricity under anaerobic conditions. MFC performance varies amongst different types of soils due to distinctive soil properties. This study assesses the performance of soil MFCs filled with four typical Chinese soils and explores key factors regulating bioelectricity generation and tetracycline degradation. Except for the MFCs filled with black soil, tetracycline degradation rates improved in soil MFCs, particularly in those filled with Chao soil, which enhanced the degradation rate by 39% relative to the corresponding control. Additionally, soil MFCs filled with Chao soil exhibited the highest charge output of 1347⯱â¯357C, which was 100-499% higher than that of MFCs with other soils. According to redundancy analysis, soil particle size, pH, conductivity and dissolved organic carbon content showed positive association with tetracycline degradation and charge output, while the adsorption of tetracycline had a negative association with degradation rate. Thus, the adsorption of tetracycline restricted its removal efficiency in soil MFCs, and high soil conductivity and large particle size promoted electron transfer, enhancing biocurrent intensity, which increased tetracycline degradation efficiency.