Modeling approach for Ti3C2 MXene-based fluorescent aptasensor for amoxicillin biosensing in water matrices.

Amoxicillin, a member of the penicillin family, is primarily utilized for the treatment of various bacterial infections affecting ears, nose, throat, urinary tract, and skin. Given its widespread application in medicine, agriculture, environment, and food industry, the precise and sensitive detection of amoxicillin is important. This study introduces a novel approach to developing a sensitive and selective fluorescent aptasensor relying on fluorescence resonance energy transfer (FRET) for the specific detection of amoxicillin. The carboxyfluorescein-labeled aptamer serves as a energy donor, while MXene functions as an energy acceptor, and acting as a quencher. To achieve optimal detection efficiency, a dual optimization strategy utilizing RSM-CCD and ANN-GA was used to fine-tune experimental conditions. The fluorescence measurements revealed an expansive linear range extending from 100 to 2400 ng mL-1, accompanied by an exceptionally low detection limit of 1.53 ng mL-1. Additionally, it shows an excellent selectivity towards amoxicillin over other antibiotics commonly found in water matrices. The aptasensor demonstrates good stability and reproducibility; effectiveness of the aptasensor was validated by testing in real water samples. This remarkable sensitivity and broad dynamic range affirm the efficacy aptasensor in accurately detecting varying concentrations of amoxicillin in wastewater bodies.

Efficient porphyrin integrated UiO-66 probes for ratiometric fluorescence sensing of antibiotic residues in milk.

Dual-emissive fluorescence probes were designed by integrating porphyrin into the frameworks of UiO-66 for ratiometric fluorescence sensing of amoxicillin (AMX). Porphyrin integrated UiO-66 showed dual emission in the blue and red region. AMX resulted in the quenching of blue fluorescence component, attributable to the charge neutralization and hydrogen bonds induced energy transfer. AMX was detected using (F438/F654) as output signals. Two linear relationships were observed (from 10 to 1000 nM and 1 to 100 µM), with a limit of detection of 27 nM. The porphyrin integrated UiO-66 probe was used to detect AMX in practical samples. This work widens the road for the development of dual/multiple emissive fluorescence sensors for analytical applications, providing materials and theoretical supporting for food, environmental, and human safety.

Detection of Pharmaceutically Active Compounds in Tap Water Samples by Direct Injection HPLC/MS-MS: A Danger Signal in Deficiency in Residue Management.

To date, there is an increased risk to public health and the environment due to the presence of pharmaceutically active compounds within drinking water supply and distribution networks. Owing to this, a direct injection-HPLC/MS-MS method was developed for the simultaneous determination of 16 active pharmaceutical compounds in tap water samples: amoxicillin, ampicillin, cephalexin, cefotaxime, cefuroxime, ciprofloxacin, clarithromycin, clindamycin, chloramphenicol, cyproterone, erythromycin, flutamide, spironolactone, sulfamethoxazole, tamoxifen, and trimethoprim. Limits of detection (LOD) ranged from 0.2 to 6.0 µg/L while quantification limits (LOQ) from 0.3 to 20 µg/L. Recovery percentages were between 70 and 125%. Total analysis time was short, with all compounds being resolved in less than 2.1 min. Of the 22 tap water samples collected and analyzed, the highest concentrations corresponded to amoxicillin (147 µg/L) and ciprofloxacin (44 µg/L). The findings could set a precedent for establishing safe levels of these compounds and increasing standards for tap water quality in this region.

Electrooxidation of amoxicillin in aqueous solution with graphite electrodes: Optimization of degradation and deciphering of byproducts using HRMS.

Contaminants of emerging concern (CECs) such as antibiotics have become a matter of worry in aquatic environments worldwide. Their presence in the environment has been increasing due to the inability of conventional wastewater and water treatments to annihilate them. Hence, attempts have been made to remove CECs using electrochemical oxidation (EO). Present study employed the low cost, active carbon based graphite sheet electrodes as anode and cathode to oxidize and degrade Amoxicillin (AMOX)- a ß-lactum thiazolidine antibiotic. Optimization studies found pH 9, 45 mA cm-2, 81 cm2 electrode surface area, 6 mM electrolyte concentration and 60 min treatment time to be optimal for AMOX removal. Studies with varying concentrations of AMOX (20 mg L-1, 30 mg L-1 and 40 mg L-1) found that increase in concentrations of AMOX require higher current densities and treatment time for better TOC removal. High performance liquid chromatography photo diode array (HPLC-PDA) studies found 94% removal for 40 mg L-1 of AMOX at optimal conditions with 90% COD and 46% TOC removal. High resolution mass spectrometry (HRMS) studies using Ultra performance liquid chromatography-quadrupole time of flight-mass spectrometry (UPLC-Q-ToF-MS) identified major degradation mechanisms to be hydroxylation, ß-lactum ring cleavage, breakage of thiazolidine ring chain from the aromatic ring and piperazinyl ring formation. The final byproducts of AMOX oxidation were carboxylic acids.

Applied potential assisted biodegradation of amoxicillin (AMX) using bacterial consortium isolated from a waste dump site.

Antibiotics have revolutionized modern day living with their ability to effectively treat infectious diseases in humans and animals. However, the release of antibiotic compounds into the environment has led to toxic consequences. To reduce this environmental impact, it is important to employ an inexpensive and rational technology to reduce the amount of antibiotics released into the ecosystem. This study aims to explore the potential of using a bio-electrochemical system (BES) to remove Amoxicillin (AMX) from artificially contaminated soil using a microbial consortium and pure culture isolates. Under desired conditions, including an initial AMX concentration of 150 mg/L, 5 mg/L tryptone as the nitrogen source, pH of 7, temperature of 29 °C, an applied potential of 0.8 V, and an inoculum dose of 1% w/v, the BES showed a maximum degradation of 97.9% of AMX with the microbial consortium (HP03, HP09, and HP10). High performance liquid chromatography-mass spectrometry was used to analyse the intermediates formed during the degradation process, and the pathway elucidated revealed complete degradation of AMX. Phytotoxicity studies and degradation efficiency against multiple antibiotics confirmed the environmental significance of the BES with microbial consortium. Overall, this study highlights the potential of BES as a cost-effective and efficient method for reducing the release of antibiotics into the environment and provides valuable insights into the mechanisms and pathways of antibiotic degradation.

Sensitive and rapid method for the quantitation of amoxicillin in minipig plasma and milk by LC-MS/MS: A contribution from the IMI ConcePTION project.

The IMI project ConcePTION was launched to fill the knowledge gap of using medicines during pregnancy and lactation. To achieve this goal, several studies are being conducted, including the bioanalysis of amoxicillin in minipig plasma and milk. A high-throughput, robust and reliable liquid chromatography tandem mass spectrometry method was developed and validated according to FDA and EMA guidelines to determine the concentrations of amoxicillin in a large number of minipig plasma and milk samples. Chromatographic separation was achieved on a Luna® Omega Polar C18, 1.6 µm, 100 × 2.1 mm column, with a mobile phase consisting of 0.1% formic acid in water and acetonitrile. Mass spectrometry used in a positive ionization mode and the transitions m/z 366.1 â†’ 349.2 was selected to monitor amoxicillin, while m/z 370.1 â†’ 114.15 was selected for the stable isotope labelled internal standard. This method features a linear quantification range of 10 ng/mL - 10 µg/mL, recovery of not less than 94.1%, a single sample extraction method for both plasma and milk matrices, and an analysis runtime of 5 min.

The application of a new recyclable photocatalyst γ-Fe2O3@SiO2@ZIF8-Ag in the photocatalytic degradation of amoxicillin in aqueous solutions.

This pilot study synthesized the γ-Fe2O3@SiO2@ZIF8-Ag nanocomposites via the hydrothermal method to study its potential use in amoxicillin degradation as a novel photocatalyst in aqueous solutions under visible light radiation. Various diagnostic methods were used to determine the morphology and functional structure of the photocatalyst, and the results confirmed its proper formation. Complete degradation of AMX was obtained at a pH of 5, catalyst dosage of 0.4 g/L, AMX concentration of 10 mg/L, and reaction time of 60 min. The efficiency of the degradation was diminished when anions were present in the reaction medium, and the order of their effect was SO42- < Cl- < NO3- < HCO3-. Biodegradability (BOD5/COD ratio) increased from 0.20 to 0.68 after 120 min of photocatalytic treatment, with a COD removal of 87.54% and a TOC removal of 74.88%. Through the experimental trapping of electrons, we found the production of reactive species, such as hydroxyl radical (•OH), superoxide (O2•-), and holes (h+), in the photocatalysis reactor and that •OH was the predominant species in AMX photodegradation. Comparative experiments emphasized that the oxidation process occurs with the adsorption of pollutants on the surface of the catalyst, and the photocatalyst has the potential to be activated by various light sources, including visible light, UV light, and sunlight, with an AMX decomposition above 88%. The synthesized particles can be recovered after five consecutive cycles with minimal reduction in the degradation rate (< 4%). γ-Fe2O3@SiO2@ZIF8-Ag can be considered a promising photocatalyst for use in AMX degradation due to its recyclability, easier activation by different light sources, and excellent mineralization.

Adsorption of antibiotics on different microplastics (MPs): Behavior and mechanism.

MPs can adsorb antibiotics to coexist and accumulate in the aquatic environment in the form of complexes, resulting in unforeseeable adverse consequences. The adsorption behavior and mechanism of three antibiotics amoxicillin (AMX), ciprofloxacin (CIP), and tetracycline (TC) by four MPs Polyvinyl chloride (PVC), polystyrene (PS), polypropylene (PP), and polyethylene (PE) were studied. Results showed that the adsorption of antibiotics onto MPs follows the pseudo-second-order kinetic and the Freundlich isotherm model, indicating a multilayer chemical adsorption. Combined with FTIR, XRD, and SEM analyses, the adsorption behavior was simultaneously governed by physical processes. Additionally, the equilibrium adsorption capacity was inhibited in the research concentration range of NaCl from 10 mg/L to 10 g/L. The higher the salt concentration, the more pronounced the inhibition phenomenon was. The high (9) and low (3) pH also inhibited the adsorption of antibiotics to MPs. The humic acid (HA) concentration in the range of 0-20 mg/L generally inhibited the MPs-antibiotics adsorption, but the higher HA concentration showed less inhabitation than the lower one. The adsorption inhibition of TC on the four MPs by SA also followed the above rule. However, the adsorption inhibition of sodium alginate (SA) on AMX and CIP on the four MPs was enhanced with its concentration (0-50 mg/L).

ß-MnOOH nanoplate-enhanced chemiluminescence reaction and its application to the determination of amoxicillin and salbutamol sulfate.

In this research, ß-MnOOH nanoplates (NPLs) were hydrothermally produced and then identified using several spectroscopic methods. The ß-MnOOH NPLs were used to catalyze the chemiluminescence (CL) reaction of NaHCO3 -H2 O2 . To validate the capability of the CL reaction for pharmaceutical analysis, the CL reaction of ß-MnOOH NPLs-NaHCO3 -H2 O2 reaction was exploited to develop a new method of measuring antibiotics named amoxicillin (AMX) and salbutamol sulfate (SLB). This method is based on the attenuating ß-MnOOH NPLs-NaHCO3 -H2 O2 CL reaction by the antibiotics. Calibration curves were linear in the range 3.00 × 10-5 to 1.00 × 10-3  mol L-1 for AMX and in the range 1.00 × 10-5 to 1.00 × 10-4  mol L-1 for SLB. The limits of detections obtained using the CL method for AMX and SLB were 8.90 × 10-6  mol L-1 and 5.60 × 10-6  mol L-1 , respectively. The relative standard deviations for AMX and SLB, at the 5.00 × 10-5  mol L-1 concentration, were 2.44% and 2.57% (n = 5), respectively. The study of the effect of foreign species showed that the CL method developed has the appropriate selectivity for AMX and SLB. The success of the CL method in actual samples analysis was demonstrated by accurately measuring the selected antibiotics in the pharmaceutical formulations.

Validation of a LC-MS/MS method for the quantitative analysis of four antibiotics in pig tissues and plasma to assess the risk of transfer of residues to edible matrices after exposure to cross-contaminated feed.

Cross-contamination between medicated and non-medicated feed can occur during production, processing, transport or storage of animal feed. This may lead to the presence of low concentrations of antibiotics in supposedly drug-free feed for food production animals, which potentially could also harm consumers due to residues. In addition, consumption of sub-therapeutic concentrations of antibiotics may increase the risk of emergence of resistant bacteria. In this study, LC-MS/MS methods were developed to quantify four antibiotics (sulfadimethoxine, oxytetracycline, trimethoprim and amoxicillin) in several pig matrices, i.e. plasma, muscle, liver, kidneys and faeces. All methods were validated using the accuracy profile, except for amoxicillin in faeces, for which extraction could not be optimised for low concentrations. These methods were then applied as part of an animal study during which several pigs received contaminated feed at a concentration corresponding to 2% of therapeutic dose, in order to evaluate the risk of the presence of residues in animal faeces and tissues. The results showed that sulfadimethoxine is well absorbed and accumulates in the muscle, kidneys and liver, where concentrations were higher than the maximum residue limits (MRLs) authorised in EU legislation. Conversely, oxytetracycline was mostly found in faeces as its oral absorption is very low. Trimethoprim concentrations were slightly higher than the tolerated MRL in the kidneys, but they were below this level in the other tissues. Finally, amoxicillin concentrations remained below the lower limit of quantification of the methods in all matrices.

Effects of ciprofloxacin, trimethoprim, and amoxicillin on microbial structure and growth as emerging pollutants reaching crop soils.

The presence of emerging pollutants, and specifically antibiotics, in agricultural soils has increased notably in recent decades, causing growing concern as regards potential environmental and health issues. With this in mind, the current study focuses on evaluating the toxicity exerted by three antibiotics (amoxicillin, trimethoprim, and ciprofloxacin) on the growth of soil bacterial communities, when these pollutants are present at different doses, and considered in the short, medium, and long terms (1, 8 and 42 days of incubation). Specifically, the research was carried out in 12 agricultural soils having different physicochemical characteristics and was performed by means of the leucine (3H) incorporation method. In addition, changes in the structure of soil microbial communities at 8 and 42 days were studied in four of these soils, using the phospholipids of fatty acids method for this. The main results indicate that the most toxic antibiotic was amoxicillin, followed by trimethoprim and ciprofloxacin. The results also show that the toxicity of amoxicillin decreases with time, with values of Log IC50 ranging from 0.07 ± 0.05 to 3.43 ± 0.08 for day 1, from 0.95 ± 0.07 to 3.97 ± 0.15 for day 8, and from 2.05 ± 0.03 to 3.18 ± 0.04 for day 42, during the incubation period. Regarding trimethoprim, 3 different behaviors were observed: for some soils the growth of soil bacterial communities was not affected, for a second group of soils trimethoprim toxicity showed dose-response effects that remained persistent over time, and, finally, for a third group of soils the toxicity of trimethoprim increased over time, being greater for longer incubation times (42 days). As regards ciprofloxacin, this antibiotic did not show a toxicity effect on the growth of soil bacterial communities for any of the soils or incubation times studied. Furthermore, the principal component analysis performed with the phospholipids of fatty acids results demonstrated that the microbial community structure of these agricultural soils, which persisted after 42 days of incubation, depended mainly on soil characteristics and, to a lesser extent, on the dose and type of antibiotic (amoxicillin, trimethoprim or ciprofloxacin). In addition, it was found that, in this research, the application of the three antibiotics to soils usually favored the presence of fungi and Gram-positive bacteria.

Antibiotics and microbial community-induced antibiotic-resistant genes distribution in soil and sediment in the eastern coastline of China.

The health risk of antibiotic-resistant genes (ARGs) has been a global concern, while the report on occurrence and prevalence of ARGs in coastal zone is relatively scarce. This study investigated typical ARGs in soil and sediment in coastal line of eastern China and assessed its relationship with antibiotics and heavy metals as well as microbial community. Results showed that eight ARGs were all detected in the samples, and ß-lactam resistance gene blaTEM reached the highest absolute abundance (6.28 × 107 ~ 6.48 × 108 copies/g) and relative abundance (2.3 × 10-2 copies/16S rRNA) among samples. Amoxicillin and tetracycline were most frequently detected with the average concentration of 2.28 µg/kg and 3.48 µg/kg, respectively. Cr and Zn were found to be most abundant heavy metals with average value of 82.1 and 59.1 mg/kg, respectively. Proteobacteria, Campilobacterota, Bacteroidota, and Firmicutes were dominant phyla in most samples, while bacterial community varied significantly among samples. Redundancy analyses (RDA) showed that microbial community and antibiotics (amoxicillin and tetracycline) were driving factors of ARGs distribution, while heavy metals were not significantly correlated with ARGs. This study is helpful to understand the fate of ARGs in coastal zone.

Simulation and risk assessment of typical antibiotics in the multi-media environment of the Yangtze River Estuary under tidal effect.

Frequent human activities in estuary areas lead to the release of a large number of antibiotics, which poses a great threat to human health. However, there are very limited studies about the influence of the special natural phenomena on the occurrence and migration of antibiotics in the environment. In this study, we simulated the migration and transformation of six typical antibiotics, including oxytetracycline (OTC), tetracycline (TC), norfloxacin (NOR), ofloxacin (OFX), erythromycin (ETM), and amoxicillin (AMOX), in the environmental media from 2011 to 2019 in the Yangtze River Estuary, by using the level III multi-media fugacity model combined with the factor of tides. The simulation results showed that the most antibiotics mainly existed in soil and sediment while erythromycin were found mainly in water. The concentrations of antibiotics in air, freshwater, seawater, groundwater, sediment, and soil were 10-23-10-25, 0.1-12 ng/L, 0.02-7 ng/L, 0.02-16 ng/L, 0.1-13 ng/g, and 0.1-15 ng/g respectively. Sensitivity analysis showed that the degradation rate (Km) and the soil-to-water runoff coefficient (Kl) were important model parameters, indicating that hydrodynamic conditions had a significant impact on the migration of antibiotics in various environmental phases in estuarine areas. Tide can enhance the exchange between water bodies and cause the transformation of the antibiotics from freshwater to seawater and groundwater, which improved the accuracy of the model, especially the seawater and soil phase. Risk assessments showed that amoxicillin, erythromycin, ofloxacin, and norfloxacin posed a threat to the estuarine environment, but the current source of drinking water did not affect human health. Our findings suggested that, when one would like to exam the occurrence and migration of antibiotics in environment, more consideration should be given to the natural phenomena, in addition to human activities and the nature of antibiotics.

Effective photocatalytic degradation of amoxicillin using MIL-53(Al)/ZnO composite.

A promising hierarchical nanocomposite of MIL-53(Al)/ZnO was synthesized as a visible-light-driven photocatalyst to investigate the degradation of amoxicillin (AMX). MIL-53(Al)/ZnO ultrafine nanoparticles were obtained by preparing Zn-free MIL-53Al and employing it as a reactive template under hydrothermal and chemical conditions. The synthesized nanocomposite (MIL-53(Al)/ZnO) has a low content of Al > 1.5% with significantly different characterizations of the parent compounds elucidated by various analyses such as SEM, TEM, XRD, EDX, and UV-Vis. The effect of operational parameters (catalyst dose (0.2-1.0 g/L), solution pH (3-11), and initial AMX concentration (10-90 mg/L)) on the AMX removal efficiency was studied and optimized by the response surface methodology. A reasonable goodness-of-fit between the expected and experimental values was confirmed with correlation coefficient (R2) equal to 0.96. Under the optimal values, i.e., initial AMX concentration = 10 mg/L, solution pH ~ 4.5, and catalyst dose = 1.0 g/L, 100% AMX removal was achieved after reaction time = 60 min. The degradation mechanism and oxidation pathway were vigorously examined. The AMX degradation ratios slightly decreased after five consecutive cycles (from 78.19 to 62.05%), revealing the high reusability of MIL-53(Al)/ZnO. The AMX removal ratio was improved with enhancers in order ([Formula: see text]> H2O2 > S2O8-2). The results proved that 94.12 and 98.23% reduction of COD were obtained after 60 and 75 min, respectively. The amortization and operating costs were estimated at 3.3 $/m3 for a large-scale photocatalytic system.

A short review of human exposure to antibiotics based on urinary biomonitoring.

Antibiotics play a role in preventing and treating infectious diseases and also contribute to other health risks for humans. With the overuse of antibiotics, they are widely distributed in the environment. Long-term exposure to multiple antibiotics may occur in humans through medication and dietary intake. Therefore, it is critical to estimate daily intake and health risk of antibiotics based on urinary biomonitoring. This review compares the strengths and weaknesses of current analytical methods to determine antibiotics in urine samples, discusses the urinary concentration profiles and hazard quotients of individual antibiotics, and overviews correlations of antibiotic exposure with the risk of diseases. Liquid chromatography-tandem mass spectrometry is most applied to simultaneously determine multiple types of antibiotics at trace levels. Solid-phase extraction with a hydrophilic-lipophilic balance adsorbent is commonly used to extract antibiotics in urine samples. Fifteen major antibiotics with relatively higher detection frequencies and concentrations include sulfaclozine, trimethoprim, erythromycin, azithromycin, penicillin V, amoxicillin, oxytetracycline, chlortetracycline, tetracycline, doxycycline, ofloxacin, enrofloxacin, ciprofloxacin, norfloxacin, and florfenicol. Humans can be easily at microbiological effect-based risk induced by florfenicol, ciprofloxacin, azithromycin, and amoxicillin. Positive associations were observed between specific antibiotic exposure and obesity, allergic diseases, and mental disorders. Overall, the accessible, automated, and environmentally friendly methods are prospected for simultaneous determinations of antibiotics at trace level in urine. To estimate human exposure to antibiotics more accurately, knowledge gaps need to be filled up, including the transformation between parent and metabolic antibiotics, urinary excretion proportions of antibiotics at low-dose exposure and pharmacokinetic data of antibiotics in humans, and the repeated sampling over a long period in future research is needed. Longitudinal studies about antibiotic exposure and the risk of diseases in different developmental windows as well as in-depth research on the pathogenic mechanism of long-term, low-dose, and joint antibiotic exposure are warranted.

Total removal of amoxicillin from water using magnetic core nanoparticles functionalized with silver.

Framed in the problem of emerging pollutants, in this work we introduce a novel procedure for the total removal of amoxicillin from water samples using magnetic nanoparticles functionalized with nanometric silver (Fe3O4@AgNPs). Experimental conditions such as pH, contact time, temperature, as well as adsorbate and adsorbent doses have been studied to achieve the total adsorption for different concentrations of amoxicillin in water. Particularly, for concentrations 10 and 100 mg L-1, a maximum removal efficiency of 100% was reached at room temperature and pH = 7 after 15 min of contact time between adsorbent and water samples under gentle shaking. The doses of adsorbent employed to remove 10 and 100 mg L-1 of amoxicillin were 100 and 500 µL, respectively. Characterization of the adsorbent surfaces was performed by Scanning and Transmission Electron Microscopy, Energy Dispersive X-ray Spectroscopy, BET analysis and Fourier-transform infrared spectroscopy. Recycling studies were carried out employing 500 µL of NaOH solution 1 M during 15 min in order to explore desorption and reuse of the adsorbent, showing that Fe3O4@AgNPs remains unaltered and can be used for two more additionally adsorption cycles, exhibiting 93% adsorption efficiency after the third regeneration. The characterization of equilibrium isotherms and thermodynamics reveal a Langmuir-type endothermic chemisorption.

Degradation of amoxicillin by newly isolated Bosea sp. Ads-6.

Amoxicillin (AMX), one of the micro-amount hazardous pollutants, was frequently detected in environments, and of great risks to environments and human health. Microbial degradation is a promising method to eliminate pollutants. In this study, an efficient AMX-degrading strain, Ads-6, was isolated and characterized. Strain Ads-6, belonging to the genus Bosea, was also able to grow on AMX as the sole carbon and nitrogen source, with a removal of ~60% TOC. Ads-6 exhibited strong AMX-degrading ability at initial concentrations of 0.5-2 mM and pH 6-8. Addition of yeast extract could significantly enhance its degrading ability. Many degradation intermediates were identified by HPLC-MS, including new ones such as two phosphorylated products which were firstly defined in AMX degradation. A new AMX degradation pathway was proposed accordingly. Moreover, the results of comparative transcriptomes and proteomes revealed that ß-lactamase, L, D-transpeptidase or its homologous enzymes were responsible for the initial degradation of AMX. Protocatechuate branch of the beta-ketoadipate pathway was confirmed as the downstream degradation pathway. These results in the study suggested that Ads-6 is great potential in biodegradation of antibiotics as well as in the bioremediation of contaminated environments.

Health risk assessment of antimicrobial residues in sheep carcasses marketed in Kuwait.

A total of 450 samples comprising 150 each of muscles, livers and kidneys were collected from 150 sheep carcasses in Kuwait and tested by both Rapid Premi®Test kits for rapid detection of antimicrobial-positive samples, and the High-performance liquid chromatography (HPLC) for residual determination of amoxicillin, tetracycline, oxytetracycline, and tylosin. Premi test revealed that 82%, 64% and 100% of the muscle, liver and kidney samples examined, respectively were positive for antimicrobials. HPLC analysis revealed mean concentrations (µg/kg) of 45.26, 148.17, 103.18, and 71.80 for amoxicillin, oxytetracycline, tetracycline, and tylosin respectively in muscles; 64.43, 263.15, 177.04, and 112.94, respectively in livers; and 53.12, 368.21, 196.40, and 138.63, respectively in kidneys. Although many samples exceeded the maximum residue limit (MRL) of Codex Alimentarius, the assessment of dietary exposure to the antimicrobials tested through consumption of sheep meat and organs did not constitute any health hazards in the different age groups of Kuwaiti population.

High efficiency three-dimensional electrochemical treatment of amoxicillin wastewater using Mn-Co/GAC particle electrodes and optimization of operating condition.

In this work, Mn-Co/GAC particle electrode was prepared by loading Mn and Co as catalysts on granular activated carbon (GAC) and used in a three-dimensional (3D) electrochemical system for mineralization of amoxicillin wastewater. Observation results by SEM, EDS and XRD confirmed that Mn and Co catalysts were successfully loaded onto GAC. The electrochemical properties were measured using an electrochemical workstation. Mn-Co/GAC had a much higher oxygen evolution potential (1.46V) than GAC (1.1V), which demonstrated that it could effectively reduce the oxygen evolution side reaction. In addition, Mn-Co/GAC had an electrochemically active surface area 1.34 times that of GAC and a much smaller mass transfer resistance than GAC, which could provide favorable conditions for the degradation of pollutants. The investigation of the influences of single operating parameters on total organic carbon (TOC) removal rate and electrical energy consumption (EEC) indicated that current density and treatment time had the greatest effect. In order to maximize TOC removal rate and minimize EEC, optimization of operating parameters was also carried out using response surface method in combination with central composite design. The optimal operating parameters were determined as current density of 5.68 mA/cm2, electrolyte concentration of 0.127M, particle electrode dosage of 31.14g and treatment time of 120min. Under this optimum operating condition, TOC removal rate of 85.24% and amoxicillin removal rate of 100% could be achieved with a low EEC of 0.073 kWh/g TOC. In addition, TOC removal rate and EEC were significantly improved compared to the use of bare GAC as particle electrode under the same operating conditions, demonstrating the excellent electrocatalytic ability of the new particle electrode Mn-Co/GAC. A possible mechanism of enhanced amoxicillin and TOC removal was also recommended. In summary, the 3D electrochemical method using Mn-Co/GAC particle electrodes is a suitable choice for amoxicillin wastewater treatment.

Chitosan coated Fe3O4@Cd-MOF microspheres as an effective adsorbent for the removal of the amoxicillin from aqueous solution.

In this work, for the first time, a new magnetic cadmium-based MOFs (Fe3O4@Cd-MOF) was successfully synthesized in a green way and then modified with chitosan (CS) in the microsphere form (Fe3O4@Cd-MOF@CS). The obtained materials were fully characterized by several techniques. In the following, the efficiency of Fe3O4@Cd-MOF@CS was explored for the removal of amoxicillin (AMX). The outcome of the adsorption study showed that the removal efficiency is affected by CS and reaches its optimum at pH 8 and contact time of 240 min. Under optimized conditions, over 75% of AMX was removed. The kinetic and the isotherm of the adsorption were fit with the pseudo-second-order model and the Langmuir adsorption isotherm respectively. Eventually, the maximum adsorption capacity was obtained ~103.09 mg/g. Interestingly, these findings convince that the newly prepared Fe3O4@Cd-MOF@CS could be proposed as a promising magnetically separable adsorbent for antibiotic contaminants removal from the aqueous solution.