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1.
The present study firstly aimed at developing a multi-residue method to identify and quantify 38 veterinary antibiotics (belonging to five different classes) not only for raw swine wastewater but also for wastewater differently treated by different units. The proposed method is based on a solid-phase extraction procedure and ultra high performance liquid chromatography with mass spectrometry. For sample preparation, the optimal loading sample volume was selected as 50 mL, the pH of which was adjusted to approximately 3.0 using formic acid. Then 0.1 g/L ethylenediaminetetraacetic acid disodium salt was added. The recovery rates for different types of wastewaters were in the range of 35.94–124.51% and the relative standard deviations were in the range of 0.36–14.62%. All the matrix standard curves exhibited high linearity (0.9956–0.9999). The matrix effects for the target antibiotics ranged from –61.73 to +148.75%. To ensure the practicality of the method, we performed the detection of the actually added concentration to determine method detection limits and quantitation limits. The quantitation limits of most of the target antibiotics were 0.04 μg/L, except for spiramycin (0.1 μg/L) and roxithromycin (0.2 μg/L). This optimized and validated method was applied to analyze antibiotic residues in swine water samples from four swine farms.  相似文献   
2.
Growing concerns related to antibiotic residues in environmental water have encouraged the development of rapid, sensitive, and accurate analytical methods. Single-drop microextraction has been recognized as an efficient approach for the isolation and preconcentration of several analytes from a complex sample matrix. Thus, single-drop microextraction techniques are cost-effective and less harmful to the environment, subscribing to green analytical chemistry principles. Herein, an overview and the current advances in single-drop microextraction for the determination of antibiotics in environmental water are presented were included. In particular, two main approaches used to perform single-drop microextraction (direct immersion-single-drop microextraction and headspace-single-drop microextraction) are reviewed. Furthermore, the impressive analytical features and future perspectives of single-drop microextraction are discussed in this review.  相似文献   
3.
建立了一种基于QuEChERS前处理技术,结合超高效液相色谱-串联质谱(UPLC-MS/MS)和内标法,快速测定土壤中19种氟喹诺酮类抗生素(FQs)残留的分析方法。5. 0 g土壤样品添加200μg/kg基质匹配同位素内标后,经20 m L 0. 1 mol/L EDTA-McIlvaine缓冲液和乙腈混合溶剂(体积比1∶1)提取,基质分散固相萃取(150 mg无水MgSO4、15 mg PSA、15 mg C18)净化后,采用UPLC-MS/MS进行测定。质谱分析采用电喷雾电离,正离子扫描,多反应监测模式。在优化条件下,19种抗生素的相关系数(r~2)为0. 992~0. 998,检出限为0. 2~1. 0μg/kg,定量下限为1. 0~5. 0μg/kg;在10、50、200μg/kg加标水平下的回收率为65. 2%~104%,相对标准偏差(n=5)不大于14%。该方法操作简单快速、准确度高,适用于土壤中氟喹诺酮类抗生素残留的检测。  相似文献   
4.
Peptides have important biological functions. However, their susceptibility to proteolysis limits their applications. We demonstrated here for the first time, that poly(2‐oxazoline) (POX) can work as a functional mimic of peptides. POX‐based glycine pseudopeptides, a host defense peptide mimic, had potent activities against methicillin‐resistant S. aureus, which causes formidable infections. The POX mimic showed potent activity against persisters that are highly resistant to antibiotics. S. aureus did not develop resistance to POX owning to the reactive oxygen species related antimicrobial mechanism. POX‐treated S. aureus is sensitive to common antibiotics, demonstrating no observable antimicrobial pressure or cross‐resistance in using antimicrobial POX. This study highlights POX as a new type of functional mimic of peptides and opens new avenues in designing and exploring peptide mimetics for biological functions and applications.  相似文献   
5.
Antimicrobial cationic amphiphiles derived from aminoglycoside pseudo‐oligosaccharide antibiotics interfere with the structure and function of bacterial membranes and offer a promising direction for the development of novel antibiotics. Herein, we report the design and synthesis of cationic amphiphiles derived from the pseudo‐trisaccharide aminoglycoside tobramycin and its pseudo‐disaccharide segment nebramine. Antimicrobial activity, membrane selectivity, mode of action, and structure–activity relationships were studied. Several cationic amphiphiles showed marked antimicrobial activity, and one amphiphilic nebramine derivative proved effective against all of the tested strains of bacteria; furthermore, against several of the tested strains, this compound was well over an order of magnitude more potent than the parent antibiotic tobramycin, the membrane‐targeting antimicrobial peptide mixture gramicidin D, and the cationic lipopeptide polymyxin B, which are in clinical use.  相似文献   
6.
Aminoglycosides are a relevant class of antibiotics widely used by medics and veterinaries. There are a variety of reasons that make their determination relevant, such as quality control, environment and food contamination assessment, drug-release studies, among others. The lack of a chromophore makes aminoglycoside spectrophotometric detection particularly challenging, often requiring derivatization. In this work, an indirect detection method, making use of imidazole as a probe, applying CZE was successfully tested. It did not require derivatization, which simplified the sample preparation. Suitable figures of merit were obtained; recoveries between 95 and 105%, adequate repeatability and precision, correlation coefficients (r) above 0.998, and limits of detection (LODs) of 3.2 and 11 mg/L for gentamicin and paromomycin, respectively. As a proof-of-concept, it was also applied in a simple controlled release experiment that was well fitted using the Hill equation.  相似文献   
7.
In this study, a novel solid-liquid-solid extraction approach, which was termed ‘microwave-assisted micro-solid-phase extraction’ (MAE-μ-SPE), was developed. Target analytes were extracted from the sample into extraction solvent enhanced by microwave field, following adsorption by the adsorbent in the micro-solid-phase extraction device. Without any clean-up steps, the extracts were analysed by high performance liquid chromatography coupled with ultra-violet detector. The MAE-μ-SPE approach was developed for the extraction of four tetracycline antibiotics residues in environmental soil, sludge and atmospheric particulate matters. Variables affecting extraction procedures were systematically investigated. Low detection limits of 0.1–6.3 ng/g and low quantification limits of 0.33–20.7 ng/g were achieved under optimised conditions. The recoveries of antibiotics ranged from 70.6% to 110.5% with relative standard deviation of less than 15.1%. The predominance was showed when compared to conventional MAE and μ-SPE method. According to the results, MAE-μ-SPE was proved to be a simple and effective sample preparation method for the analysis of trace organic contaminants in environmental samples.  相似文献   
8.
The urge for the development of a more efficient antibiotic crystalline forms led us to the disclosure of new antibiotic coordination frameworks of pyrazinamide, a well-known drug used for the treatment of tuberculosis, with some of the novel compounds unravelling improved antimycobacterial activity. Mechanochemistry was the preferred synthetic technique to yield novel compounds, allowing the reproduction of a 1D zinc framework, the synthesis of a novel hydrogen bonding manganese framework, and three new compounds with silver. The structural characterization of the novel forms is presented along with stability studies. The increased antimicrobial activity of the new silver-based frameworks against Escherichia coli, Staphylococcus aureus, and Mycobacterium smegmatis is particularly relevant.  相似文献   
9.
In this study, a new, economical and green method was reported for synthesizing Fe3O4@CuO nanoparticles without adding any surfactants using Euphorbia polygonifolia extract as a renewable, mild and safe reducing agent and effective stabilizer. The green synthesized NPs were analyzed by various methods such as XRD, FESEM, FT-IR, EDS, VSM, UV–visible, DRS, BET and TGA-DTA. Based on the BET analysis, the Fe3O4@CuO NP had a surface area of 69.20 m2/g. The FTIR analysis verified the existence of different functional groups of phytochemicals from Euphorbia polygonifolia extract which were accountable for the NPs formation. The catalytic performance of the catalyst for the degradation of metronidazole, ciprofloxacin and cephalexin antibiotics was examined in aqueous mediums at room temperature. The results showed an extraordinary catalytic performance, easy reusability and long-term stability of the composite for reducing antibiotic pollution. In this process, the effects of environmental conditions such as initial pH of the environment, initial concentration of antibiotics, the concentration of modified photocatalyst and reaction time were studied. According to the results, at the optimal conditions, the highest removal efficiency for metronidazole, ciprofloxacin and cephalexin antibiotics using Fe3O4@CuO nanoparticles, were 89%, 94%, and 96%, respectively. Also, it was observed that even after recycling, the NPs presents good nanocatalytic stability for the degradation of antibiotics. Using the NPs for five cycles did not significantly alter the photocatalyst efficiency, showing that the photocatalytic stability of the NPs was excellent.  相似文献   
10.
Cystobactamids belong to the group of arene-based oligoamides that effectively inhibit bacterial type IIa topoisomerases. Cystobactamid 861-2 is the most active member of these antibiotics. Most amide bonds present in the cystobactamids link benzoic acids with anilines and it was found that some of these amide bonds undergo chemical and enzymatic hydrolysis, especially the one linking ring C with ring D. This work reports on the chemical synthesis and biological evaluation of thirteen new cystobactamids that still contain the methoxyaspartate hinge. However, we exchanged selected amide bonds either by the urea or the triazole groups and modified ring A in the latter case. While hydrolytic stability could be improved with these structural substitutes, the high antibacterial potency of cystobactamid 861-2 could only be preserved in selected cases. This includes derivatives, in which the urea group is positioned between rings A and B and where the triazole is found between rings C and D.  相似文献   
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