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The study addresses the persistent issue of thiamphenicol (THI) accumulation in aquatic environments and its detrimental impact on biological systems. While activated carbon is commonly used for removing such organic micropollutants in advanced wastewater treatment, this research explores the innovative use of olive stones as a feedstock for activated carbon production. The novelty of this study lies in the optimization of the activated carbon preparation process using a fractional factorial design with five critical factors: concentration, heating rate, activation temperature, activation time, and impregnation ratio. By employing the methylene blue method to determine the specific surface area (SSA), the optimal conditions were identified: a phosphoric acid solid-liquid ratio of 1:2 (74.52%), a heating temperature of 550 °C at a rate of 10 °C/min, and an activation period of 120 minutes, resulting in an SSA of 53.07 m²/g. The subsequent THI adsorption tests in a fixed-bed column revealed that THI removal ef- ficiency was inversely proportional to flow rate and initial THI concentration, while positively correlated with bed height. This study fills a critical gap by demonstrating an effective, sustainable method for producing activated carbon from agricultural waste, optimizing the process parameters for maximum efficiency in micropollutant removal. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) constitute an assorted class of multi-dimensional materials that offer the potential to serve as luminescent sensors for the sensitive and selective detection of antibiotics in wastewater. Herein, a new Zn(II)-based MOF with the formula [Zn(PMA)0.5(bbp)·H2O·DMA] (1) (bbp = 3,5-bis(benzoimidazo-1-ly)pyridine; PMA = pyromellitic acid) was synthesized by a solvothermal method and characterized. Crystallographic analysis reveals that MOF 1 possesses a 4,4-connected net with the Schläfli symbol {32·4·52·6}2{32·42·52}. The fabricated MOF exhibited luminescent property and was employed as a luminescent sensor to sensitively and selectively detect tetracycline (TCY) antibiotic amongst thiamphenicol (THI), 2-methyl-4-chlorophenoxyacetic acid (MCPA), tetracycline (TCY), sulfamethoxazole (SMT), thiabendazole (TBZ), tinidazole (TDZ), sulfadiazine (SDZ), chloramphenicol (CAP), metamitron (MMT), and dinotefuran (DTF). Further, restoration of the emissive response of TCY@1 was achieved by adding salicylic acid with a concomitant bathochromic shift in the emissive response. The possible sensing mechanism and restoration of emissive response were assessed with the aid of theoretical calculations. [ABSTRACT FROM AUTHOR]

L-threo-methylsulonylphenylserine (L-threo-MSPS) is a crucial intermediate in florphenicol and thiamphenicol synthesis. L-threo-MSPS can be synthesized from L-threonine and p-methylsulfonylbenzaldehyde (p-MSBA) chiral selectively under the catalyse of L-threonine transaldolase. However, the byproduct acetaldehyde formed during the reaction process severely hinders the biosynthesis of high-quality L-threo-MSPS. The accumulated acetaldehyde reacts with L-thero-MSPS and L-threonine to form N-derivatives, and the activity of L-threonine transaldolase decreases to 14.10% even when the concentration of acetaldehyde is as low as 0.5 g/L. The acetaldehyde could be removed by aeration, and the removal efficiency is closely related to the aeration conditions, which was described by the volumetric oxygen transfer coefficient k L a in this paper. Regular aeration through pipes cannot provide enough aeration efficiency, and filters or sintered rods were used to increase the k L a value during the reaction. The residual concentration of acetaldehyde depended on the balance between the formation and removal speed of acetaldehyde. When the optimal enzyme concentration was applied and the k L a value of 5.5 min-1, the L-threo-MSPS concentration reached 293.28 mM in a 1-L reaction, and the highest conversion reached 90.03%. The need of coenzyme NAD+ was cut off in this method, and only one enzyme was applied. Consequently, the reaction was simpler and easier to control. [Display omitted] • NAD+-independent biosynthesis of L-threo-MSPS with transaldolase and aeration. • The derivatization of L-threo-MSPS and L-threonine by acetaldehyde in the reaction. • The relation between acetaldehyde removal efficiency and the kLa value of aeration. • Increased conversion of L-threo-MSPS from 60% to 90% by aeration. [ABSTRACT FROM AUTHOR]

We investigated fourteen antibiotics, three illegal drugs, and two toxic elements in commercially available gastropods from southeast China. The data revealed high detection frequencies (DFs) for florfenicol (61.32%), florfenicol amine (47.33%), and thiamphenicol (39.88%), with maximum concentrations of 1110, 2222, and 136 μg/kg wet weight (ww), respectively. The DFs of illegal drugs were 3.54% for leucomalachite green and 0.3% for chloramphenicol. The average levels of Cd and As were 1.17 and 6.12 mg/kg ww, respectively. All chemicals presented diverse DFs in different sampling months. The highest DFs of florfenicol, florfenicol amine, and thiamphenicol were in July. The health risk assessment showed that targeted hazard quotients (THQs) of antibiotics, Cd, and As for children, teens, and adults were all less than one. Notably, the toxic elements (Cd and As) were identified as the primary health risk in gastropods, contributing to over 90% of the total THQs. [ABSTRACT FROM AUTHOR]

Objective. To determine the minimum inhibitory concentrations of thiamphenicol and thiamphenicol glycinate acetylcysteinate against clinically significant microorganisms and determine their efficacy against microbial biofilms. Materials and Methods. This study included 48 clinical strains isolated from the sputum of patients with respiratory tract infections (16 S. pneumoniae, K. pneumoniae and S. aureus strains). Antimicrobial susceptibility testing was performed using broth microdilution method. Biofilm formation culturing with antibiotics, N-acetylcysteine and their combinations was assessed in Mueller-Hinton broth and brain heart broth in 96-well plates. Biofilms are fixed with 2,5% glutaraldehyde solution, stained with 0,25% crystal violet solution, which is extracted by 33% acetic acid solution. Results. The MIC of thiamphenicol and thiamphenicol glycinate acetylcysteinate (in terms of thiamphenicol) were the same for 87,5% of strains. Thiamphenicol and thiamphenicol glycinate acetylcysteinate have been confirmed high antimicrobial activity against S. pneumoniae strains (MIC50 0,5 mg/l, MIC90 1-2 mg/l). Cultivation with chloramphenicol, thiamphenicol, thiamphenicol glycinate acetylcysteinate, combination of chloramphenicol and thiamphenicol with N-acetylcysteine contributed to significant reduction in the optical density of S. pneumoniae biofilms. Thiamphenicol increased biofilm formation in some resistant S. aureus and K. pneumoniae. Combination based on N-acetylcysteine neutralized this effect. Conclusions. Potentiation of antibacterial activity of thiamphenicol by N-acetylcysteine against S. pneumoniae biofilms has been shown.

Violative chemical residues in edible tissues from food-producing animals are of global public health concern. Great efforts have been made to develop physiologically based pharmacokinetic (PBPK) models for estimating withdrawal intervals (WDIs) for extralabel prescribed drugs in food animals. Existing models are insufficient to address the food safety concern as these models are either limited to 1 specific drug or difficult to be used by non-modelers. This study aimed to develop a user-friendly generic PBPK platform that can predict tissue residues and estimate WDIs for multiple drugs including flunixin, florfenicol, and penicillin G in cattle and swine. Mechanism-based in silico methods were used to predict tissue/plasma partition coefficients and the models were calibrated and evaluated with pharmacokinetic data from Food Animal Residue Avoidance Databank (FARAD). Results showed that model predictions were, in general, within a 2-fold factor of experimental data for all 3 drugs in both species. Following extralabel administration and respective U.S. FDA-approved tolerances, predicted WDIs for both cattle and swine were close to or slightly longer than FDA-approved label withdrawal times (eg, predicted 8, 28, and 7 days vs labeled 4, 28, and 4 days for flunixin, florfenicol, and penicillin G in cattle, respectively). The final model was converted to a web-based interactive generic PBPK platform. This PBPK platform serves as a user-friendly quantitative tool for real-time predictions of WDIs for flunixin, florfenicol, and penicillin G following FDA-approved label or extralabel use in both cattle and swine, and provides a basis for extrapolating to other drugs and species.

The aim of this investigation was to reveal the pattern of disposal process of thiamphenicol (TAP) in Chinese soft-shelled turtle after oral (PO) and intramuscular (IM) administration routes. TAP concentration levels in Chinese soft-shelled turtle plasma and multi-tissues were measured by HPLC-MS/MS. Pharmacokinetic (PK) parameters of TAP were estimated using WinNolin software based on the non-compartmental analysis. Compared with IM route, higher absorption, longer elimination time and greater AUC0-∞ value for TAP in plasma were observed after PO treatment. It indicated that Chinese soft-shelled turtle has a higher bioavailability for TAP following PO administration than IM medication. For tissue distribution, higher TAP concentrations were also found following PO medication than IM administration. The prescribed medication dosage of TAP (17.5 mg/kg bw) against susceptible strains with MIC should be below 0.22 mg/L (PO) and 0.13 mg/L (IM) based on the values of Cmax/MIC >10 and AUC0–24 h/MIC >125. TAP elimination pattern was investigated, and skirt was suggested as residual target tissue. Withdrawal time (WT) of TAP was calculated using WT 1.4 software, and the recommended WT was 17 d (391 ℃-day). The present investigation can serve as reference data for TAP use in Chinese soft-shelled turtle.

To our knowledge, ours is the first study to investigate the annual fluxes, environmental fate, and ecological risks of five categories of antibiotics from the Wuhan section of the Yangtze River (China). All the 24 antibiotics we tested for were detected in water, with total concentrations of 17.11–867.2 ng/L (mean: 63.69 ng/L), and 19 antibiotics were detected in sediment, at 0.02–287.7 ng/g (mean: 16.54 ng/g). Sulfonamides, amphenicols, and macrolides were the three most prominent antibiotic classes in water, and fluoroquinolones were the most prominent in sediment. Farming activities (animal husbandry and aquaculture) are proposed as the largest contributors to antibiotic pollution in the Wuhan section of the Yangtze River according to the Unmix model, followed by municipal wastewater and mixed sources. Higher pollution levels were observed downstream (combined discharge of these sources). Monthly monitoring data (12 months) were used to estimate antibiotic annual fluxes, with 101.5 t (uncertainty: 5.6%) in the Wuhan section of the Yangtze River. Risk assessments showed that erythromycin, clarithromycin, and azithromycin posed medium and high ecological risks and were found in 9%–35% and 1.8%–3.7% of all water samples, respectively; enrofloxacin, clarithromycin, azithromycin, florfenicol, and thiamphenicol posed medium resistance risks in 1.9%–16.7% of waters in the Wuhan section of the Yangtze River. Our results have filled data gaps on antibiotic sources, annual fluxes, and resistance risk in the Wuhan section of the Yangtze River and demonstrated the importance of further management of antibiotic use in the studied areas. Environ Toxicol Chem 2023;42:605–619. © 2022 SETAC [ABSTRACT FROM AUTHOR]

Natural nanoparticles (NNP) are ubiquitous in natural water and can interact with other contaminants, causing ecotoxic effects on aquatic nontarget organisms. However, the impact of NNPs on the ecotoxicity of antibiotics remains largely unknown. This work investigated the acute toxicity, chronic effect, and oxidative response and damage in Daphnia magna co-exposed to phenicol antibiotics (chloramphenicol, thiamphenicol) and different concentrations of NNPs (10 mg/L: environmentally relevant concentration; 100 mg/L: a high concentration that caused no apparent immobilization in D. magna). The results showed that the acute toxicity of chloramphenicol was increased by 10 mg/L NNPs but decreased by 100 mg/L NNPs; both concentrations of NNPs increased and decreased acute toxicities of thiamphenicol and chloramphenicol + thiamphenicol treatments, respectively. After long-term exposure, phenicol antibiotics (1 μg/L) and NNP (10 mg/L) mixtures in environmentally relevant concentrations significantly affected the reproduction of D. magna but did not influence their growth. The catalase activity, reduced glutathione level, and malonaldehyde content in D. magna also varied with the NNPs concentrations. Notably, the lowest concentration of thiamphenicol and chloramphenicol + thiamphenicol combined with NNPs significantly increased the malondialdehyde content in D. magna compared with the control, indicating membrane lipid peroxidation occurred in daphnids. This study suggests that the toxic effects of contaminants and NNPs on aquatic organisms should be considered thoroughly to avoid underestimating the hazard of these pollutants in the actual aquatic environment. [ABSTRACT FROM AUTHOR]

Antibiotic resistance mediated by bacterial enzyme inactivation plays a crucial role in the degradation of antibiotics in the environment. Chloramphenicol (CAP) resistance by enzymatic inactivation comprises nitro reduction, amide bond hydrolysis, and acetylation modification. However, the molecular mechanism of enzymatic oxidation of CAP remains unknown. Here, a novel oxidase gene, cmO, was identified and confirmed biochemically. The encoded CmO oxidase could catalyze the oxidation at the C-19 and C-39 positions of CAP and thiamphenicol (TAP) in Sphingobium sp. strain CAP-1. CmO is highly conserved in members of the family Sphingomonadaceae and shares the highest amino acid similarity of 41.05% with the biochemically identified glucose methanol choline (GMC) oxidoreductases. Molecular docking and site-directed mutagenesis analyses demonstrated that CAP was anchored inside the protein pocket of CmO with the hydrogen bonding of key residues glycine (G) 99, asparagine (N) 518, methionine (M) 474, and tyrosine (Y) 380. CAP sensitivity tests demonstrated that the acetyltransferase and CmO could enable a higher level of resistance to CAP than the amide bond-hydrolyzing esterase and nitroreductase. This study provides a better theoretical basis and a novel diagnostic gene for understanding and assessing the fate and resistance risk of CAP and TAP in the environment. [ABSTRACT FROM AUTHOR]

The article presents various types of acute rhinosinusitis progression in pediatric practice depending on the duration of the disease, based on the available modern consensus papers and clinical guidelines. The main clinical terminology of the nosological forms of rhinosinusitis was determined, and aspects of their differential diagnosis and stages of the treatment were studied. The authors provided insight into disease pathogenesis, taking into account literature review data on the spectrum of the most common bacterial agents of the nose and paranasal sinuses pathologies. The available data on the treatment of rhinosinusitis are summarized from the perspective of consensus papers and modern clinical guidelines of the Ministry of Health of the Russian Federation, the use of which for the prescription of treatment is the most important quality criterion for medical care provided. A clinical case of the treatment of acute bacterial uncomplicated rhinosinusitis in a 12-year-old child is described. In this case, an aerosolized form of topical antibiotic therapy combined with a mucolytic component was used as a drug of choice alongside with the standard irrigation-elimination therapy and nasal decongestants, which gives an advantage in achieving the maximum effective concentration of the active substance at the site of inflammation. A drug with a mucoactive effect helps to decrease mucus viscosity and discharge, and at the same time facilitates the entry of an active substance into the tissues and inhibits bacterial adhesion to the epithelium of the respiratory tract. Antibacterial component – thiamphenicol, a derivative of chloramphenicol with a mechanism of action associated with inhibition of bacterial protein synthesis has a broad spectrum of action and a maximum degree of accumulation and action in the site of inflammation due to the method of delivery to the epithelium of the respiratory tract.

An immunochromatographic assay (ICA) based on surface-enhanced Raman scattering (SERS) for ultrasensitive and quantitative detection of florfenicol (FF) in food samples was developed. Au nanocubers (AuNCs) with long wavelength absorption were synthesised, characterised and used as the substrate in SERS-ICA. Immunoprobe was prepared by linking Raman reporter and the antibody against FF on AuNCs. The SERS-ICA was completed in 15 min. By measuring the Raman intensities on T lines, quantitative detection of FF was achieved. The IC50 and limit of detection (LOD) of the assay for FF were 0.027 ng mL−1 and 0.12 pg mL−1, respectively. The cross-reactivity (CR) of the assay with thiamphenicol, chloramphenicol and other four drugs were examined. The recoveries of FF in spiked samples were 88.5% ∼ 102.4% with RSD of 2.3% ∼ 7.4%. It was proven that SERS-ICA was able to rapidly detect FF in food samples with high sensitivity, accuracy and precision. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the dynamics of microbial communities and antimicrobial resistance genes (ARGs) in the chicken gut following amoxicillin and thiamphenicol treatments and potential co-selection of ARGs. To this purpose, the microbial community composition, using 16S rRNA NGS, and the abundance of ARGs conferring resistance to β-lactams and phenicols, using qPCRs, were determined. Results revealed that the administered antimicrobials did not significantly reduce the gut microbiota diversity, but changed its composition, with taxa (e.g. Gallibacterium and Megamonas) being enriched after treatment and replacing other bacteria (e.g. Streptococcus and Bifidobacterium). Positive correlations were found between ARGs (e.g. cmlA, blaCMY-2, and blaSHV) and the relative abundance of specific taxa (e.g. Lactobacillus and Subdoligranulum). The selective pressure exerted by both amoxicillin and thiamphenicol resulted in an increased abundance of ARGs conferring resistance to β-lactams (e.g. blaTEM-1, blaSHV, and blaCTX-M1-like) and phenicols (e.g. floR and cmlA). These findings, together with the co-occurrence of genes conferring resistance to the two antimicrobial classes (e.g. blaTEM-1 and cmlA), suggest a possible interaction among antimicrobials on resistance emergence, possibly due to the presence of mobile genetic elements (MGEs) carrying multiple resistance determinants. [ABSTRACT FROM AUTHOR]

Activated carbon can be applied to the treatment of wastewater loading with different types of pollutants. In this paper, a kind of activated carbon in granular form (GAC) was utilized to eliminate antibiotics from an aqueous solution, in which Tetracycline (TC), Thiamphenicol (THI), and Sulfamethoxazole (SMZ) were selected as the testing pollutants. The specific surface area, total pore volume, and micropore volume of GAC were 1059.011 m2/g, 0.625 cm3/g, and 0.488 cm3/g, respectively. The sorption capacity of GAC towards TC, THI, and SMZ was evaluated based on the adsorption kinetics and isotherm. It was found that the pseudo-second-order kinetic model described the sorption of TC, THI, and SMZ on GAC better than the pseudo-first-order kinetic model. According to the Langmuir isotherm model, the maximum adsorption capacity of GAC towards TC, THI, and SMZ was calculated to be 17.02, 30.40, and 26.77 mg/g, respectively. Thermodynamic parameters of ΔG0, ΔS0, and ΔH0 were obtained, indicating that all the sorptions were spontaneous and exothermic in nature. These results provided a knowledge base on using activated carbon to remove TC, THI, and SMZ from water. [ABSTRACT FROM AUTHOR]

Effects and mechanism of carbonyl cyanide chlorophenylhydrazone (CCCP) on antimicrobial activity of florfenicol (FF) and thiamphenicol (TAP) were investigated against amphenicol-resistant Actinobacillus pleuropneumoniae and Pasteurella multocida isolated from diseased swine. Broth microdilution and time-kill assays indicated that CCCP dose-dependently and substantially (4-32 fold MIC reduction) improved amphenicol antimicrobial activity. When combined with CCCP at the lowest literature reported dose (2-5 μg/mL), 85% FF resistant A. pleuropneumoniae and 92% resistant P. multocida showed significantly reduced FF MICs (≥ 4-fold). In contrast, none or few of the susceptible A. pleuropneumoniae and P. multocida had FF MICs reduction ≥ 4-fold. 90% FF resistant A. pleuropneumoniae and 96% resistant P. multocida carried the floR gene, indicating strong association with the FloR efflux pump. With CCCP, the intracellular FF concentration increased by 71% in floR+ resistant A. pleuropneumoniae and 156% in floR+ resistant P. multocida strains but not the susceptible strains. The degree of reduction in TAP MICs was found consistently in parallel to FF for both bacteria. Taken together, partially attributed to blockage of drug-efflux, the combination of FF or TAP with CCCP at sub-cytotoxic concentrations was demonstrated and showed feasibility to combat amphenicol-resistant A. pleuropneumoniae and P. multocida isolated from diseased swine. [ABSTRACT FROM AUTHOR]

Herein, N, S co-doped carbon quantum dots (N, S-CDs) with high absolute quantitative yield (Abs-QY) of 50.2% were produced by hydrothermal treatment of food residue crayfish shells. A new detection method of thiamphenicol (TAP) and its analogues was established by discovering the obvious fluorescence response between TAP and N, S-CDs, which achieved a wide linear range of 20–300 μg·L−1 with a detection limit (LOD) of 11.12 μg·L−1. This novel probe exhibited strong sensitivity and shows rapid response in complex food matrices (overall detection time is less than 45 min) mainly induced by static quenching. Spiked food sample recovery ranged from 97.3 to 99.34%. Further, the cell experiments of N, S-CDs were conducted, and the cell viability remained 91.76% under high concentration of N, S-CDs due to the environmentally friendly materials. The low cytotoxicity and good cytocompatibility make these N, S-CDs compatible for cell bioimaging and intracellular detection of TAP. [ABSTRACT FROM AUTHOR]

[Display omitted] • •Co-MgO-CMS was prepared by MOFs derivatization. • •Co-MgO-CMS exhibited high activity and stability in ozonation of thiamphenicol. • •Metallic Co in Co-MgO-CMS could interact directly with O 3 to produce reactive oxygen species. Cobalt-magnesium oxide–carbon microsphere composite (Co-MgO-CMS), Cobalt-carbon nanosheet composite (Co-CNS), and magnesium oxide–carbon nanorod composite (MgO-CNR) were synthesized by the MOFs self-sacrificing template method. And they were used as the catalysts for catalytic ozonation of thiamphenicol (20 mg/L) in water at an initial pH of 7.0. The phase of Co-MgO-CMS is mainly composed of metallic cobalt, magnesium oxide and carbon according to X-ray diffraction and transmission electron microscopy analyses. Thiamphenicol removal efficiency is enhanced through Co-MgO-CMS catalytic ozonation (75.4 %, in 6 min), compared with those in ozonation alone (39.8 %), Co-CNS catalytic ozonation (43.2 %), MgO-CNR catalytic ozonation (65.1 %) and Mg-Co binary oxide (Mg 2 CoO y) catalytic ozonation (69.0 %). Self-increasing of solution pH, protonated hydroxyl groups and electron transfer on metallic Co and lattice Co2+ are advantageous for the ozone decomposition into reactive oxygen species in Co-MgO-CMS catalytic ozonation. Owing to the metallic Co in Co-MgO-CMS, the electron transfer ability of Co-MgO-CMS is better than that of Mg 2 CoO y according to the in situ electrochemical test. Moreover, electron transfers directly from metallic Co to ozone. While protonated hydroxyl groups are the key for electron transfer on lattice Co2+. A possible degradation pathway for thiamphenicol in Co-MgO-CMS catalytic ozonation is proposed according to the detected intermediates. This work provides insight into improvement on electron transfer ability of concerted acid-base catalyst in heterogeneous catalytic ozonation. [ABSTRACT FROM AUTHOR]

Previous studies implied that elevated exposure to amphenicol antibiotics may induce increased oxidative stress. However, the effects of amphenicol antibiotics exposure on oxidative stress damage in human have not been well studied. This study examined the associations between amphenicol antibiotics exposure and oxidative damage biomarkers in school children. Three major amphenicols including chloramphenicol (CAP), thiamphenicol (TAP), florfenicol (FF) and two biomarkers of 8-hydroxydeoxyguanosine (8-OHdG) for oxidative DNA damage and 8-oxo-7,8- dihydroguanosine (8-OHG) for oxidative RNA damage were measured in 414 morning urine samples collected from 70 school children in Shanghai, China. School children were exposed to CAP, TAP, and FF with median concentrations of 1.37, 0.36, and 0.06 μg/g Cre, respectively. Linear mixed models revealed that an interquartile range (IQR) increase of urinary TAP was positively associated with 7.75%(95% CI: 4.40%, 11.1%) increase of 8-OHdG and 7.48%(95% CI: 2.49%, 15.6%) increase of 8-OHG, respectively; in addition, CAP was associated with elevated 8-OHdG. Although FF was not found to be significantly associated with either 8-OHdG or 8-OHG, it is warranted to further investigate FF and its metabolites levels in relation to oxidative stress in future study. Our findings provide new evidence for the effects of exposure to TAP and CAP on nucleic acid oxidative damage in Children. [ABSTRACT FROM AUTHOR]

A study is performed of the sorption of chloramphenicol, florfenicol, and thiamphenicol on magnetic hypercrosslinked polystyrene (HCPS/Fe3O4). Magnetic HCPS is obtained via the sorption of Fe3O4 nanoparticles on commercially available HCPS Diapak P-3. The specific surface areas and parameters of the porous structure of the magnetic HCPS are determined by means of low-temperature nitrogen adsorption. It is found that introducing Fe3O4 nanoparticles into the HCPS matrix slightly lowers the specific surface area of the sorbent (from 1132 to 1080 m2/d) and the volume of pores, but these characteristics are strong enough to use the resulting composite as a sorbent. It is established that the HCPS-based magnetic sorbent exhibits superparamagnetic properties. The saturation magnetization is 1.7 emu/g, enough to extract the sorbent from the solution under the action of the magnetic field of a permanent magnet. It is shown that magnetic HCPS can be used for the group sorption concentration of amphenicols via magnetic solid-phase extraction. [ABSTRACT FROM AUTHOR]

Amphenicols are broad-spectrum antibiotics. Despite their benefits, they also present toxic effects and therefore their presence in animal-derived food was regulated. Various analytical methods have been reported for their trace analysis in food and environmental samples, as well as in the quality control of pharmaceuticals. Among these methods, the electrochemical ones are simpler, more rapid and cost-effective. The working electrode is the core of any electroanalytical method because the selectivity and sensitivity of the determination depend on its surface activity. Therefore, this review offers a comprehensive overview of the electrochemical sensors and methods along with their performance characteristics for chloramphenicol, thiamphenicol and florfenicol detection, with a focus on those reported in the last five years. Electrode modification procedures and analytical applications of the recently described devices for amphenicol electroanalysis in various matrices (pharmaceuticals, environmental, foods), together with the sample preparation methods were discussed. Therefore, the information and the concepts contained in this review can be a starting point for future new findings in the field of amphenicol electrochemical detection. [ABSTRACT FROM AUTHOR]

Thiamphenicol (TAP) is an amphenicol antibiotic, which has a broad-spectrum inhibitory effect on both gram-positive and gram-negative bacteria. Since it is widely used in animals and aquaculture, its residues in environment may bring potential risk for human health and ecosystems. While TAP can be removed through conventional physical or chemical methods, its bioremediation using microorganisms is less studied. Here, we report the removal of TAP by a bacterial strain, Aeromonas hydrophila HS01, which can remove more than 90.0% of TAP in a living cell-dependent manner. Our results indicated that its removal efficiency can be greatly affected by the growth condition. Proteomics studies revealed a number of differentially expressed proteins of HS01 in the presence of TAP, which may play critical roles in the transportation and degradation of TAP. All these results indicate bacterial strain A. hydrophila HS01 is a new microbial resource for efficiently removing TAP, and may shed new insights in developing bioremediation approaches for TAP pollution. [ABSTRACT FROM AUTHOR]

The accumulation of antimicrobial residues in edible animal products and aquaculture products could pose health concerns to unsuspecting consumers. Hence, this study aimed to develop a validated method for simultaneous quantification of chloramphenicol (CAP), thiamphenicol (TAP), florfenicol (FF), and florfenicol amine (FFA) in beef, pork, chicken, shrimp, eel, and flatfish using a quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction method coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Primary-secondary amine (PSA) and MgSO4 were used for sample purification. The analytes were separated on a reversed-phase analytical column. The coefficients of determination for the linear matrix-matched calibration curves were ≥0.9941. Recovery rates ranged between 64.26 and 116.51% for the four analytes with relative standard deviations (RSDs) ≤ 18.05%. The calculated limits of detection (LODs) and limits of quantification (LOQs) were 0.005–3.1 and 0.02–10.4 μg/kg, respectively. The developed method was successfully applied for monitoring samples obtained from local markets in Seoul, Republic of Korea. The target residues were not detected in any tested matrix. The designed method was versatile, sensitive, and proved suitable for quantifying residues in animal-derived products.

Amphenicol antibiotics including chloramphenicol (CAP), florfenicol (FF) and thiamphenicol (TAP) have been widely used in aquaculture and veterinary to treat various infections. Because of their high toxicity, it is important to detect these amphenicol antibiotics simultaneously. Using the monoclonal antibody against CAP (mAbCAP) binding CAP only and the mAbFF recognizing both FF and TAP, the two antibodies were covalently coupled to CNBr-activated Sepharose-4B for the simultaneous extraction of CAP, FF and TAP from samples. The bound CAP, FF and TAP were eluted from the Sepharose-4B and measured by LC–MS/MS. The extraction conditions of the two-antibodies-immobilized immunoaffinity clean-up (IAC) for CAP, FF and TAP were optimized and the maximum capacity was investigated. The extraction efficiency of IAC for CAP, FF and TAP was 1.1–2.1 times higher than that of SPE. The LC–MS/MS coupled with IAC was a powerful analytical method for the detection of CAP, FF and TAP simultaneously. [ABSTRACT FROM AUTHOR]

To explore the difference of antibiotic adsorption performance of biochar prepared at different pyrolysis temperatures, three biochars (P600, P700, P800) were prepared by pigeon feces through oxygen restricted pyrolysis at the temperature of 600, 700, 800 °C. The differences in elemental composition, surface morphology, functional groups and physicochemical properties of the three biochars were analyzed to investigate the effects of different factors (pH value, salt ion strength, etc.) on the adsorption of thiamphenicol (TAP) in water. The results illustrate that as the pyrolysis temperature increases from 600 °C to 800 °C, the pH value, mass fraction of oxygen element, specific surface area and pore diameter, as well as TAP equilibrium adsorption capacity of pigeon feces biochar increase significantly. At 25 °C, initial mass concentration of TAP is 20 mg/L, t = 4 h, the equilibrium adsorption capacity of P800 on TAP (33.63 mg/g) is significantly higher than that of P600 on TAP (5.72 mg/g), indicating that pyrolysis temperature has a significant influence on the adsorption performance of TAP by pigeon feces biochar. The adsorption process of the three pigeon feces biochars is best fitted by the Elovich kinetic equation and Freundlich isothermal model, which implies that the adsorption process is a multi-phase and multi-layer chemical adsorption on heterogeneous surfaces. The hydrophobic interaction, hydrogen bonding and electrostatic interaction are the possible chemical adsorption mechanisms. [ABSTRACT FROM AUTHOR]

Herein, N, S co-doped carbon quantum dots (N, S-CDs) with high absolute quantitative yield (Abs-QY) of 50.2% were produced by hydrothermal treatment of food residue crayfish shells. A new detection method of thiamphenicol (TAP) and its analogues was established by discovering the obvious fluorescence response between TAP and N, S-CDs, which achieved a wide linear range of 20–300 μg·L−1 with a detection limit (LOD) of 11.12 μg·L−1. This novel probe exhibited strong sensitivity and shows rapid response in complex food matrices (overall detection time is less than 45 min) mainly induced by static quenching. Spiked food sample recovery ranged from 97.3 to 99.34%. Further, the cell experiments of N, S-CDs were conducted, and the cell viability remained 91.76% under high concentration of N, S-CDs due to the environmentally friendly materials. The low cytotoxicity and good cytocompatibility make these N, S-CDs compatible for cell bioimaging and intracellular detection of TAP.

Amphenicols are broad-spectrum antibiotics. Despite their benefits, they also present toxic effects and therefore their presence in animal-derived food was regulated. Various analytical methods have been reported for their trace analysis in food and environmental samples, as well as in the quality control of pharmaceuticals. Among these methods, the electrochemical ones are simpler, more rapid and cost-effective. The working electrode is the core of any electroanalytical method because the selectivity and sensitivity of the determination depend on its surface activity. Therefore, this review offers a comprehensive overview of the electrochemical sensors and methods along with their performance characteristics for chloramphenicol, thiamphenicol and florfenicol detection, with a focus on those reported in the last five years. Electrode modification procedures and analytical applications of the recently described devices for amphenicol electroanalysis in various matrices (pharmaceuticals, environmental, foods), together with the sample preparation methods were discussed. Therefore, the information and the concepts contained in this review can be a starting point for future new findings in the field of amphenicol electrochemical detection.

[Display omitted] • A consortium proficient in TAP degradation was domesticated from activated sludge. • TAP metabolic fate, mechanism and cross-feeding were first unraveled by muti-omics. • Key species Hydrogenophaga and Bosea inactivated TAP by oxidation and acetylation. • Hydrogenophaga sp. stored carbon and nitrogen by synthesizing cyanophycin and PHB. Thiamphenicol (TAP), a typical veterinary antibiotic, is emerging as a contaminant in livestock, poultry, and aquaculture environments. Addressing this concern, this study domesticated a TAP-degrading consortium in a lab-scale activated sludge bioreactor, demonstrating efficient degradation of up to 200 mg/L TAP within 50 h and elimination of antimicrobial activity. The microbial compositions, cross-feeding interactions, and underlying metabolic mechanisms were unveiled through multi-omics. TAP was modified at two hydroxyl groups for the initial step in three pathways including oxidation at C 3 -OH, dehydrogenation at both C 1 -OH and C 3 -OH, and acetylation at C 3 -OH. Hydrogenophaga (MAG1 and MAG2) and Bosea (MAG9) were implicated in oxidation and acetylation of TAP, respectively. Aromatic compounds and 2,2-dichloroacetic acid (DCA) were the principal downstream metabolites of TAP. MAG9 (Bosea), MAG10 (Rubrivivax), and MAG13 (Hyphomicrobium) were predicted as DCA degraders, while MAG4 (Xanthobacteraceae, Ga0077548) and MAG10 (Rubrivivax) conducted the catabolism of aromatic compounds. Therefore, consortium members collaborated to efficiently reduce and detoxify TAP. Furthermore, the co-metabolism of TAP and extracellular substrates supported the microbial populations' growth. Genomic traits and transcriptional profiles suggested that the dominant Hydrogenophaga (MAG1) could store carbon and nitrogen by synthesizing cyanophycin and polyhydroxybutyrate biopolymers. Ultimately, this comprehensive understanding of TAP biodegradation will aid in formulating efficient biotreatment strategies for TAP-contaminated environments. [ABSTRACT FROM AUTHOR]

l- threo - p -methylsulfonylphenylserine (compound 1b ) is the main intermediate of florfenicol, and its efficient synthesis has been the subject of current research. Herein, Burkholderia diffusa l-threonine transaldolase ( Bu LTTA) was rationally designed based on the sequence-structure-function relationship. A mutant M4 (Asn35Ser/Thr352Asn) could produce 35.5 mM 1b with 88.8% conversion and 93.8% diastereoselectivity, 314 and 129% of the values observed for wild-type Bu LTTA. Molecular dynamics simulations indicated that the shortened distance between key active site residues and the transition state (PLP- 1b ) and the improved hydrogen bond force enhanced the catalytic performance of the M4 variant. Then, the mutant M4 was combined with K. kurtzmanii alcohol dehydrogenase ( Kk ADH) to eliminate the Bu LTTA-inhibiting byproduct acetaldehyde, and a cosubstrate was added to regenerate the ADH cofactor NADH. Under optimized conditions, the yield of 1b reached 115.2 mM with a conversion of 96% and a diastereoselectivity of 95.5%. This work provides a new strategy for the efficient and sustainable production of 1b .

Thiamphenicol (TAP) and florfenicol (FFC) combination has in vitro and in vivo synergistic activity against fish bacterial pathogens. However, a lack of information on its pharmacokinetics (PK) and pharmacodynamics (PD) in fish limits its further application. Therefore, this study aimed to develop and validate analytical methods for simultaneous detection and quantification of TAP and FFC in tilapia plasma and muscle plus skin samples and to determine the PK in freshwater tilapia at 30 ± 0.32 °C after a single oral dose of 5 mg kg−1 TAP +3.75 mg kg−1 FFC. Antimicrobial concentrations were analyzed by HPLC-MS. The PK characteristics were estimated by a non-compartmental model (linear up/log down). Precise, and sensitive methods were developed using ethyl acetate (plasma) and a modified QuEChERS (muscle plus skin) for extraction. Both methods were successfully applied to analyze the plasma and muscle plus skin samples in the PK study. The highest concentrations of TAP and FFC were detected at 0.5 h (6.34 and 3.34 μg mL−1) and 16 h (8.20 and 11.37 μg mL−1) post-administration in plasma and muscle, respectively. There was no significant difference between the peak concentration and apparent volume of distribution during the terminal phase of each antimicrobial in different tissues. However, the peak time, the area under the concentration-time curve, and mean residence time were higher in the muscle, for both antimicrobials (P < 0.05). The calculated PK parameters and the curve obtained for both antimicrobials emphasize their fast absorption and distribution even when used in combination. The results from this study could help establish antimicrobial susceptibility testing interpretative categories and design rational dosing regimens for TAP and FFC combination. • Plasma and muscle plus skin pharmacokinetics of TAP and FFC in tilapia after single oral administration of TAP + FFC combination were determined for the first time. • The developed and validated HPLC-MS/MS method is precise and sensitive for the simultaneous determination of TAP and FFC in fish plasma and muscle plus skin. • TAP and FFC had fast absorption and distribution in freshwater tilapia reared at 30 ± 0.32 °C. • Peak concentrations in both tissues were 2–22 times higher than the reported MIC values of the antimicrobials against several sensitive fish pathogens. [ABSTRACT FROM AUTHOR]

Membrane fouling limited the application of membrane distillation (MD) process in resource recovery. In this research, the peroxymonosulfate (PMS) enhanced Fe(III) coagulation process was proposed and proved its effectiveness in eliminating natural organic matter (NOM) and emerging organic contaminants (EOCs). Fe(III)/PMS process significantly enhanced the removal of dissolved organic carbon (DOC), turbidity, and UV 254 , compared to conventional Fe(III) coagulation. Thiamphenicol (TAP) represented the EOCs in the digestate, and Fe(III)/PMS could significantly degrade TAP (86 % degradation). In this course, phenols/quinones served as electron shuttles to induce the Fe(III)/Fe (II) redox cycle. The activation of PMS was boosted, generating the primary reactive substance sulfate (SO 4 −) radical with intense oxidative properties. In addition, membrane distillation achieved recovery of 93 % of TAN from coagulation effluent without membrane fouling. No tryptophan-like, tyrosine-like, xanthate, and other soluble microbial byproducts were detected on the membrane surface following Fe(III)/PMS pretreatment. The innovation of this study was revealing that the complexation of Fe(III) with NOM could promote Fe (II) regeneration and enhance PMS activation, active substance formation and contaminants degradation. New insights into the role of NOM in the Fe(III)/Fe(II) redox cycle were gained and the development of advanced oxidation process (AOP) coupled membrane technology was promoted to mitigate membrane fouling. [Display omitted] • A coupled coagulation/advanced oxidation process-membrane distillation system was established for ammonia recovery. • The Fe(III)/PMS enhanced coagulation system significantly mitigated membrane fouling. • NOM could mediate the redox cycle of the Fe(III)/Fe(II). • The mechanism of degradation of TAP via Fe(III)/PMS system was proposed. • SO 4 •- was the prominent reactive radical in the Fe(III)/PMS process. [ABSTRACT FROM AUTHOR]

● High yields of DCAM and DCAA are formed during ozonation of phenicol antibiotics. ● The transformation pathways of phenicol antibiotics during ozonation are investigated. ● DCAM is completely transformed to DCAA during post-chlorination of ozonation effluent. ● The molar yield of DCAA is ∼100 % during phenicol antibiotic abatement by ozonation and post-chlorination. ● Post-chloramination of ozonation effluent increases the yields of DCAM and DCAA moderately. This study investigated the formation of dichloroacetamide (DCAM) and dichloroacetic acid (DCAA) from the abatement of three phenicol antibiotics (PABs, chloramphenicol, thiamphenicol, and florfenicol) during ozonation and post-chlor(am)ination. Results show that the three PABs have a low ozone reactivity (k O3 = 0.11‒0.12 M−1 s−1), and therefore are mainly abated through the hydrogen abstraction mechanism by hydroxyl radicals (•OH) during ozonation. During PAB degradation, the carboxamide moiety in the parent molecules can be cleaved off by •OH attack and thus gives rise to DCAM. The formed DCAM can then be further oxidized by O 3 and/or •OH to DCAA as a more stable transformation product (TP). When the three PABs were adequately abated (abatement efficiency of ∼82 %‒95 %), the molar yields of DCAM and DCAA were determined to be 2.79 %‒4.71 % and 32.9 %‒37.2 %, respectively. Furthermore, post-chloramination of the ozonation effluents increased the yields of DCAM and DCAA slightly to 4.20 %‒6.45 % and 39.0 %‒41.1 %, respectively. In comparison, post-chlorination eliminated DCAM in the solutions, but significantly increased DCAA yields to ∼100 % due to the further conversion of DCAM and other ozonation TPs to DCAA by chlorine oxidation. The results of this study indicate that high yields of DCAM and DCAA can be generated from PAB degradation during ozonation, and post-chlorination and post-chloramination will result in very different fates of DCAM and DCAA in the disinfected effluent. The formation and transformation of DCAM and DCAA during PAB degradation need to be taken into account when selecting multi-barrier treatment processes for the treatment of PAB-containing water. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • The MIMFMs were endowed with superb hydrophilicity and permeability. • The MIMFMs had selective recognition and retention for three amphenicol drugs. • An efficient MIMFMs extraction strategy in syringe filter was developed. • MIMFMs-UHPLC-MS/MS analysis method for three amphenicols was established. In this study, molecularly imprinted microfiltration membranes (MIMFMs) based on polydopamine and metal–organic framework were innovatively proposed, and successfully prepared for capturing thiamphenicol, florfenicol and chloramphenicol from milk samples through syringe filter device. The provision of PDA and coupling of MOF particles enabled the filter membranes to have great permeability and binding capacity. Cleverly, hydrophilicity and heightened rebinding selectivity (IF = 2.42) of filter membranes was provided using two functional monomers (methacrylate and acrylamide), and microfiltration-grade composite membranes were generated by adjusting the imprinting polymerization time. The combination of the selective filter membranes and the syringe filter devices can effectively simplify the operation process, minimize the extraction time and reduce the tested sample volume. The method was validated by coupling with ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) and obtained a good correlation (r 2 > 0.99). The limit of detection (LOD) of three analytes was 0.0800–0.6583 µg kg−1 and the mean recovery ranged from 85.5% to 91.2% within relative standard deviations (RSDs) less than 8.2%. Finally, an effective MIMFMs-UHPLC-MS/MS method was established for the recognition and detection of three amphenicol antibiotics in milk samples. The MIMFMs filtration technique offered in this work provides valuable science references and potential application prospects for complicated sample pretreatment. [ABSTRACT FROM AUTHOR]

Overuse of the amphenicol antibiotics chloramphenicol (CHL) and thiamphenicol (TAP) poses a great threat to ecosystem safety and human health. The strain, Nocardioides sp. LMS-CY, Nocardioides sp. QY071 and Nocardioides sp. L-11A, classified as a gram-positive actinomycete, harbours a complete CHL metabolic pathway. However, the metabolic genes (clusters) involved in the entire pathway in gram-positive actinomycetes are still limited. Here, chlOR LMS , chlOR QY071 and chlOR L-11A completely from the actinomycete Nocardioides spp. were found to act on the C 1 -OH of the CHL/TAP side chain, directly converting CHL/TAP to 4-nitrobenzaldehyde (PNBD)/4-methylsulfonyl benzaldehyde (PMBD) and transforming PNBD/PMBD into 4-nitrobenzyl alcohol (PNBM)/4-methylsulfonyl phenyl methanol (PMBM). Furthermore, oxidoreductases can transform PNBM into 4-nitrobenzoate (PNBA). The oxidoreductases ChlOR LMS , ChlOR QY071 and ChlOR L-11A were all classified as cellobiose dehydrogenases from the glucose methanol choline (GMC) family. Based on the Swiss-Prot database, ChlOR QY071 exhibited a lower identity (27.12%-35.10% similarity) with the reported oxidoreductases. Enzymatic and molecular docking analyses showed that ChlOR QY071 and ChlOR L-11A from the two similar genomes were remarkably more effective in metabolizing CHL than ChlOR LMS . Overall, the detailed resistance mechanism of CHL/TAP by actinomycete strains isolated from soil and livestock manure will provide insights into the occurrence of CHL/TAP resistance genes in the environment, resistance risk and bioremediation of CHL/TAP-contaminated environments., (© 2023 Applied Microbiology International and John Wiley & Sons Ltd.)

Florfenicol is a broad-spectrum antibiotic commonly used in the U.S. to treat respiratory and enteric infections in goats in an extra-label manner, which requires scientifically based withdrawal intervals (WDIs) for edible tissues. This study aimed to determine the depletion profiles for florfenicol and florfenicol amine in plasma and tissues samples and to estimate WDIs for goats following subcutaneous injection of 40 mg/kg florfenicol, twice, 96 h apart. The samples were collected up to 50 days after the second dose. Pharmacokinetic parameters were calculated using non-compartmental analysis. Three different pharmacostatistical methods with different operational tolerances were used to calculate WDIs. The plasma half-life was 101.80 h for florfenicol and 207.69 h for florfenicol amine after the second dose. Using the FDA tolerance limit method, WDIs were 202 and 101 days, while the EMA maximum residue limit method estimated 179 and 96 days for the respective tissue concentrations to fall below limits of detection (0.12 μg/g for liver and 0.05 μg/g for kidney). This study characterizes plasma pharmacokinetics and tissue depletion profiles of florfenicol and florfenicol amine in goats following subcutaneous injections and reports estimated WDIs for food safety assessment of florfenicol in goats., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

• Antibiotics inhibited potential sedimentary N removal and increased N 2 O yield. • Antibiotics had different effect on in situ sedimentary N removal along estuary. • Permeability of sediment determines the effect of antibiotics on N removal. • ARGs can't resist the inhibition of antibiotics on microbe related to N removal. Sedimentary denitrification takes place beneath the oxic layer at the sediment-water interface, where nitrate and antibiotics need to diffuse through the overlying water. However, the antibiotics' effect on sedimentary N removal and associated N 2 O production has not been adequately investigated under in situ conditions. Here, isotope pairing techniques, including slurry incubations (potential) and intact core incubations (in situ), combined with metagenomic analysis were applied to investigate the impacts of two protein-inhibiting antibiotics (oxytetracycline and thiamphenicol) on sediment nitrogen removal in a subtropical estuary. Slurry incubations showed that the two antibiotics significantly inhibited denitrification (67–98%) and anammox (49–99%), while intact core incubations presented no antibiotic effect at upstream but significant inhibition (23%-52%) at downstream. Meanwhile, N 2 O yields were stimulated up to 20 folds in slurry incubations yet showing insignificant response in intact cores. Such contrasting results between up- and down-stream and between slurry and intact core incubations strongly indicated that permeability, which determines diffusion of antibiotics to microbes, is the key to exert the effect of antibiotics on in situ sedimentary nitrogen removal processes regardless the existence of antibiotics resistance genes. This diffusive obstruction may mitigate the toxic effect of antibiotics on nitrogen removal related microbes in natural environments. [Display omitted] [ABSTRACT FROM AUTHOR]

An environmentally friendly nitrogen-sulfur-doped carbon quantum dots molecularly imprinted fluorescent probe (N,S-CDs@MIP) was prepared for the detection of thiamphenicol (TAP) in animal-derived foods. The N,S-CDs, the core fluorophores in optical sensors, were synthesized from food waste of crayfish shells and l -cysteine and assembled to molecularly imprinted layers by Si–O–Si bond. The fluorescence produced by the novel probe in response to TAP ranged from 10.00 to 300.0 μg/L, with a detection limit of 6.20 μg/L. The developed method was also successfully applied to real milk, fish and tap water with 92.08–108.4% recoveries, which agrees with the high-performance liquid chromatography (HPLC) analysis (89.15%–110.7%). The developed probe is cheap with a short detection time (30 min) and provides a theoretical and practical operation basis for monitoring TAP residue levels. [Display omitted] • It is the first time to synthesize N,S-CDs@MIPs for detecting TAP residual in animal derived foods. • Shorter detection time towards TAP sensing within 30 min. • Recycling food waste as raw material for an environmentally friendly purpose. • The fluorophore and molecularly imprinted layer were simply assembled by Si–O–Si bond. [ABSTRACT FROM AUTHOR]

[Display omitted] • A sensitive and rapid method for the simultaneous determination of three amphenicol antibiotic (chloramphenicol, thiamphenicol and florfenicol) residues in aquaculture products was developed using UPLC-MS/MS. • A modified QuEChERS method was optimized using single-factor experiments and response surface methodology. • Mean recoveries of chloramphenicol, thiamphenicol and florfenicol in 12 types of aquaculture products ranged from 78.6% to 106.2% with RSDs less than 12.1%. • The limit of quantification of chloramphenicol, thiamphenicol and florfenicol were 0.01–0.04 μg/kg. A simple and sensitive method for the determination of amphenicol antibiotic (chloramphenicol, thiamphenicol and florfenicol) residues in aquaculture products was developed based on a response surface methodology-modified QuEChERS (quick, easy, cheap, effective, rugged and safe) method combined with ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The pretreatment method was optimized via single-factor experiments and response surface methodology based on central-composite design to maximize the extraction efficiency and purification effect. The results show that chloramphenicol, thiamphenicol and florfenicol had good linearity in the range of 0.1–50 ng/mL. The recoveries of these amphenicol antibiotics in 12 types of aquaculture products ranged from 78.6% to 106.2% with relative standard deviations less than 12.1%. The method had high sensitivity with the limit of quantification of analytes being 0.01–0.04 μg/kg. Finally, the developed method was used to analyze actual samples. The results show that this method has good application potential for detecting residues of amphenicol antibiotics in aquaculture products. [ABSTRACT FROM AUTHOR]

In this work, we used a simple ultrasonic stripping method to synthesize a bimetal MOFs at room temperature as a nanoenzyme with peroxidase-like (POD-like) activity. Through bimetal MOFs catalytic Fenton-like competitive reaction, thiamphenicol can be quantitatively dual-mode detected by fluorescence and colorimetry. It realized the sensitive detection of thiamphenicol in water, and the limits of detection (LOD) were 0.030 nM and 0.031 nM, and the liner ranges were 0.1–150 nM and 0.1–100 nM, respectively. The methods were applied to river water, lake water and tap water samples, and with satisfactory recoveries between 97.67% and 105.54%. [Display omitted] • The method of fluorescence and colorimetric dual-mode detection was built. • There were obvious fluorescence and color changes in the detection, which made it possible for on-site detection. • No complex pretreatment and a large number of toxic solvents. • Visual detection based on competitive reaction provided a new idea for pollutant detection in the future. [ABSTRACT FROM AUTHOR]