Sulfamethazine Research Articles

Quantum Dot Nanobeads Based Fluorescence Immunoassay for the Quantitative Detection of Sulfamethazine in Chicken and Milk.

Sulfamethazine (SMZ) as a broad antibiotic is widely used in livestock and poultry. However, the abuse of SMZ in livestock feed can lead to SMZ residues in food and the resistance of bacteria to drugs. Thus, a method for the detection of SMZ in food is urgently needed. In this study, quantum dot (QD) nanobeads (QBs) were synthesized by encapsulating CdSe/ZnS QDs using a microemulsion technique. The prepared QBs as signal probes were applied in lateral flow immunoassay (LFIA) for the detection of SMZ in chicken and milk. Our proposed method had limits of detection of 0.1138–0.0955 ng/mL and corresponding linear ranges of 0.2–12.5, 0.1–15 ng/mL in chicken and milk samples, respectively. The recovery of LFIA for the detection of SMZ was 80.9–109.4% and 84–101.6% in chicken and milk samples, respectively. Overall, the developed QBs-LFIA had high reliability and excellent potential for rapid and sensitive screening of SMZ in food.

Enhanced degradation mechanism of sulfamethazine by vacuum ultraviolet/persulfate

Vacuum ultraviolet/ persulfate (VUV/PS) has been a prospective method for antibiotics removal, however, the enhanced degradation mechanism is still unclear. This study compared the sulfamethazine (SMT) degradation by VUV/PS and ultraviolet/persulfate (UV/PS) processes using a photoreaction system. Results showed that the SMT degradation rate and PS activation rate by VUV/PS was 1.36 times and 1.39 times those of the conventional UV/PS process under the same dosage of PS, respectively. VUV/PS also achieved a high SMT mineralization. SO4•− and HO• played important roles in the degradation of SMT by both processes, while the role of •O2− was little. SMT concentration changed the distributions of 185 nm and 254 nm photons absorbed by solution components and altered the initiated photolysis reaction. Both processes had faster degradation rates at low initial SMT concentrations and the optimum reaction condition was at solution pH of 5. The inhibited level of the SMT degradation in both processes by four anions was in the following order: NO3−> Cl−> HCO3−>SO42. VUV/PS process was also more efficient than UV/PS for degrading environmental (200 μg/L) and high (5 mg/L) concentration of SMT from three kinds of typical water matrices (tap, river and lake water). Finally, ten photoproducts of SMT degradation by VUV (or UV) were identified, which were mainly the oxidized products of C-N, -NH2 and S-C on SMT molecules, and four degradation pathways were proposed. Overall, these findings could provide useful insights into the application of VUV/PS in efficient antibiotics removal from water.

Lanthanide metal-organic framework as a paper strip sensor for visual detection of sulfonamide with smartphone-based point-of-care platform

Antibiotic residues in aquatic environments have attracted wide attention. Considering the impacts on the ecosystem and human health, it is urgent to develop a rapid method for detecting antibiotic residues in the environment. In this work, a nanoscale lanthanide metal-organic framework Eu(TATB) with a stable red luminescence in aqueous solution is synthesized by the microemulsion method. Sulfamethazine (SMZ) is frequently most used in veterinary medicine as one of sulfonamides. Eu(TATB) can be used for sensitively and rapidly specific recognition of SMZ with low detection limit (0.67 μM) and eminent recyclability. In addition, a paper-based visual system for point-of-care (POC) monitoring SMZ is devised by both using filter paper embedded with Eu(TATB) and our developed portable smartphone-involved imaging cassette. The naked eyes can observe that the red luminescence of the paper sensor gradually fades away at the presence of SMZ. This provides a reliable and effective method for on-site detection of sulfonamide antibiotics in the field of environmental monitoring.

Panda manure biochar-based green catalyst to remove organic pollutants by activating peroxymonosulfate: Important role of non-free radical pathways

Carbonaceous materials have emerged as promising metal-free catalysts to activate peroxymonosulfate (PMS) for the degradation of organic contaminants. In this study, a low-cost carbonaceous material panda manure biochar (PBC) was prepared by pyrolysis. The panda manure biochar showed excellent performance in the degradation reaction, and the removal efficiency of sulfamethazine (SMT), which was selected as a representative organic pollutant, exceeded 85% in 40 min. The X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) characterization confirmed that the improved catalytic performance was attributed to the oxygen-containing functional groups on the surface of the biochar. Radical quenching and electron paramagnetic resonance (EPR) experiments qualitatively demonstrated that 1O2 played an important role in the degradation of SMT. Moreover, the non-radical process that dominated in the panda manure biochar/PMS system was proposed by cyclic voltammetry (CV) and linear sweep voltammetry (LSV) measurements. Sulfamethazine (SMT) was direct oxidized by the activated PMS where panda manure biochar acted as the electron transfer shuttle. The panda manure biochar /PMS system exhibited a high anti-interference ability to Cl−, HPO4−, HCO3-, SO42-, NO3−, and humic acid (HA) containing environments. This study provides a novel panda manure reuse process with high practicability, and proposes a reasonable degradation pathway for sulfamethazine (SMT) based on non-radical oxidation.

Subchronic toxicity of dietary sulfamethazine and nanoplastics in marine medaka (Oryzias melastigma): Insights from the gut microbiota and intestinal oxidative status

Antibiotics and nanoplastics are two prevalent pollutants in oceans, posing a great threat to marine ecosystems. As antibiotics and nanoplastics are highly bioconcentrated in lower trophic levels, evaluating their impacts on marine organisms via dietary exposure route is of great importance. In this study, the individual and joint effects of dietborne sulfamethazine (SMZ) and nanoplastic fragments (polystyrene, PS) in marine medaka (Oryzias melastigma) were investigated. After 30 days of dietary exposure, 4.62 mg/g SMZ decreased the Chao1 index (60.86% for females and 26.85% for males) and the Shannon index (68.95% for females and 65.05% for males) and significantly altered the structure of gut microbial communities in both sexes. The female fish exposed to 4.62 mg/g SMZ exhibited higher intestinal sod (43.5%), cat (38.5%) and gpx (39.6%) transcripts, indicating oxidative stress in the gut. PS alone at 3.45 mg/g slightly altered the composition of the gut microbiota. Interestingly, the mixture of SMZ and PS caused more modest effects on the gut microbiota and intestinal antioxidant physiology than the SMZ alone, suggesting that the presence of PS might alleviate the intestinal toxicity of SMZ in a scenario of dietary co-exposure. This study helps better understand the risk of antibiotics and nanoplastics to marine ecosystems.

Ferrate (VI) as efficient oxidant for elimination of sulfamethazine in aqueous wastes: Real matrix implications

The presence of antibiotics in aquatic environments has become a serious concern since they develop the antibiotic/multi-drug-resistant bacteria which further affect to living beings. The study intended to assess the freshly synthesized ferrate (VI) in the degradation of an important emerging micro-pollutant i.e., sulfamethazine (SMZ). Moreover, the real matrix implications are extensively conducted for implication of ferrate (VI) technology as safer and viable options. Batch reactor studies enabled the molar ratio of ferrate (VI) to sulfamethazine is 2:1 with overall rate constant 6,128 mM-2.min-1. Percentage elimination of sulfamethazine was observed Ca. 80% at initial sulfamethazine concentration 0.02 mM and ferrate (VI) dose 0.1 mM. Presence of several co-ions NaCl, Na2HPO4, NaNO3, oxalic acid and NaNO2 showed insignificant effect on elimination of sulfamethazine; whereas the efficiency of ferrate (VI) was lowered due to glycine and EDTA. Mineralization of sulfamethazine is significantly increased at lower pH value (pH 5.0). Further, the removal of sulfamethazine in the real water matrix showed that the elimination efficiency of sulfamethazine is almost unaffected as compared to the distilled water treatment. This implied that ferrate (VI) is a viable and greener option for treatment of emerging water pollutants to enhance the efficiency of existing wastewater treatment plants.

Lateral flow immunoassay based on dual spectral-overlapped fluorescence quenching of polydopamine nanospheres for sensitive detection of sulfamethazine

Herein, we propose a lateral flow immunoassay (LFIA) based on the dual spectral-overlapped fluorescence quenching of polydopamine nanospheres (PDANs) caused by the inner filter effect to sensitively detect sulfamethazine (SMZ). The fluorescence quenching LFIA device consists of four parts: absorbent pad, polyvinyl chloride pad, sample pad, and nitrocellulose membrane. Compared with traditional quenchers such as gold nanoparticles (AuNPs) with single spectral-overlapped quenching ability, PDANs can quench the excitation light and emission light of three fluorescence donors (aggregation-induced emission fluorescent microsphere, AIEFM; fluorescent microsphere, FM; and quantum dot bead, QB). The fluorescence intensity changes (ΔF) are numerically larger for PDANs-LFIA (ΔFAIEFM = 2315, ΔFFM = 979, ΔFQB = 910) than those for AuNPs-LFIA (ΔFAIEFM = 1722, ΔFFM = 833, ΔFQB =;520). AIEFM-based PDANs-LFIA exhibits a large ΔF (2315) in response to the changes in the SMZ concentration, and produces a high signal-to-noise ratio. The limit of detection (LOD) and visual LOD of LFIA based on PDANs quenching AIEFM for the detection of SMZ in chicken are 0.043 and 0.5 ng/mL, respectively. The results confirm that the proposed method can be used for the detection of hazardous materials in practical applications.

Removal of sulfamethazine using peracetic acid activated by Fe0 and UV: Efficiency and mechanism study

Peracetic acid (PAA) was successfully activated by UV and Fe0 to degrade sulfamethazine (SMT) in this study. UV/Fe0/PAA system not only could enhance SMT removal efficiency but also could reduce the energy consumption in comparison with UV, Fe0/PAA and UV/PAA systems. The RO• radical was the main radical for the degradation of SMT in UV/Fe0/PAA system and photolysis, •OH and R-O• exhibited 15.6%, 17.6% and 66.8% contribution for SMT degradation, respectively. Fourier transform infrared spectroscopy (FTIR), Scanning Electron Microscope (SEM), and X-ray photoelectron spectroscopy (XPS) were conducted to investigate the characterization of Fe0 after reaction in UV/Fe0/PAA system. The possible SMT degradation pathway was also proposed. Affecting factors such as Fe0 dosage (0–0.2 g L−1), PAA concentration (0–200 μM) and initial pH (3–9) were also studied. Cl−, NO3-, SO42- and HCO3- had a negligible adverse effect on SMT removal in this system indicating the good adaptability to inorganic ions. In addition, UV/Fe0/PAA system had the good recycle ability of Fe0 and showed a good performance in removing antibiotic in the nature fresh water. Therefore, this study notably improved the knowledge of PAA activated by Fe0 and UV and showed the potential applicability of UV/Fe0/PAA system in degrading antibiotics in nature fresh water.

MOF-derived Cu0/C activation of molecular oxygen for efficient degradation of sulfamethazine

Zero-valent copper (ZVC) has shown potential as an oxygen activator for the degradation of organic pollutants from aqueous solution. Nevertheless, the high leaching of copper ions and the demand for acidic condition limited its application. In this study, a novel mesoporous carbon hybrid loaded zero-valent copper (Cu0/C) was successfully synthesized from Cu-based metal–organic framework (Cu3(BTC)2) through a pyrolysis method and applied to efficiently degrade sulfamethazine (SMT) at neutral pH under aeration condition. The performance of Cu0/C composite for the activation of molecular oxygen was evaluated based on the effect of different reaction parameters, such as, initial SMT concentration, initial pH, activator dosage and reaction temperature. The results showed a high efficiency for SMT removal over a broad pH range (3.0–7.0). Moreover, the Cu0/C composite exhibited excellent stability and reusability for SMT degradation, and a 96.7% SMT removal and a 68.8% total organic carbon (TOC) conversion were achieved at pH 5.8 after continuous three cycles. Combined with the determination results of reactive oxidizing species and physical-chemical characterization, cupryl species (Cu3+) rather than OH produced by the reaction of the in-situ generated H2O2 with Cu+ were the major reactive species. Additionally, the possible reaction mechanism of Cu0/C activated oxygen was tentatively proposed.

Phototransformation of Graphene Oxide on the Removal of Sulfamethazine in a Water Environment.

Graphene oxide (GO) is widely used in various fields and has raised concerns regarding its potential environmental fate and effect. However, there are few studies on its influence on coexisting pollutants. In this study, the phototransformation of GO and coexisting sulfamethazine (SMZ) under UV irradiation was investigated, with a focus on the role of reactive oxygen species. The results demonstrated that GO promoted the degradation of SMZ under UV irradiation. The higher the concentration of GO, the higher the degradation rate of SMZ, and the faster the first-order reaction rate. Two main radicals, ∙OH and 1O2, both contributed greatly in terms of regulating the removal of SMZ. Cl−, SO42−, and pH mainly promoted SMZ degradation by increasing the generation of ∙OH, while humic acid inhibited SMZ degradation due to the reduction of ∙OH. Moreover, after UV illumination, the GO suspension changed from light yellow to dark brown with increasing absorbance at a wavelength of 225 nm. Raman spectra revealed that the ID/IG ratio slightly decreased, indicating that some of the functional groups on the surface of GO were removed under low-intensity UV illumination. This study revealed that GO plays important roles in the photochemical transformation of environmental pollutants, which is helpful for understanding the environmental behaviors and risks of nanoparticles in aquatic environments.

Parental exposure to sulfamethazine and nanoplastics alters the gut microbial communities in the offspring of marine madaka (Oryzias melastigma)

The individual and combined toxicity of antibiotics and nanoplastics in marine organisms has received increasing attention. However, many studies have been mostly focused on the impacts on the directly exposed generation (F0). In this study, intergenerational effects of sulfamethazine (SMZ) and nanoplastic fragments (polystyrene, PS) on the growth and the gut microbiota of marine medaka (Oryzias melastigma) were investigated. The results showed that parental exposure to dietary SMZ (4.62 mg/g) alone and PS (3.45 mg/g) alone for 30 days decreased the body weight (by 13.41% and 34.33%, respectively) and altered the composition of gut microbiota in F1 males (two months after hatching). Interestingly, parental exposure to the mixture of SMZ and PS caused a more modest decrease in the body weight of F1 males than the PS alone (15.60% vs 34.33%). The hepatic igf1 level and the relative abundance of the host energy metabolism related phylum Bacteroidetes for the SMZ + PS group were significantly higher than those for the PS group (igf1, increased by 97.1%; Bacteroidetes, 2.876% vs 0.375%), suggesting that the parentally derived mixture of SMZ and PS might influence the first microbial colonization of gut in a different way to the PS alone. This study contributes to a better understanding of the long-term risk of antibiotics and nanoplastics to marine organisms.

Mineralization of sulfonamides from wastewater using ozone-based systems.

Ozone, UV/ozone, ozone/persulfate (PS) and UV/ozone/PS systems were used to mineralize sulfonamides. Sulfadiazine (SDZ), sulfamerazine (SMR) and sulfamethazine (SMZ) were the target compounds. The novel contribution of this study is its determination of the effects of PS addition, sulfonamide structure, pH and salinity on sulfonamide mineralization in ozone-based systems. The mineralization rate of sulfonamides satisfied pseudo-first-order kinetics. The SMZ mineralization rate constant in ozone, UV/ozone, ozone/PS and UV/ozone/PS systems at pH 5 were 0.0058; 0.0101; 0.0069 and 0.0802 min-1, respectively, and those at pH 7 were 0.0075; 0.0116; 0.0083 and 0.0873 min-1, respectively. The increase in the number of methyl substituents in the heterocyclic group of SMZ and the corresponding increase in the steric hindrance of radical addition, reduced mineralization rates below those of SMR and SDZ. The addition of PS promoted sulfonamide mineralization in the ozone-based systems; conversely, salinity inhibited sulfonamide mineralization.

Tuning band structure of graphitic carbon nitride for efficient degradation of sulfamethazine: Atmospheric condition and theoretical calculation

Numerous approaches have been used to modify graphitic carbon nitride (g-C 3 N 4 ) for improving its photocatalytic activity. In this study, we demonstrated a facial post-calcination method for modified graphitic carbon nitride (g-C 3 N 4 -Ar/Air) to direct tuning band structure, i.e. , bandgap and positions of conduction band (CB)/valence band (VB), through the control of atmospheric condition without involving any additional elements or metals or semiconductors. The synthesized g-C 3 N 4 -Ar/Air could efficiently degrade sulfamethazine (SMT) under simulated solar light, i.e. , 99.0% removal of SMT with rate constant k 1 = 2.696 h −1 within 1.5 h (4.9 times than pristine g-C 3 N 4 ). Material characterizations indicated that the damaged/partial-collapsed structure and decreased nanosheet-interlayer distance for g-C 3 N 4 -Ar/Air resulted in the shift of band structure due to the denser stacking of pristine g-C 3 N 4 through oxidative exfoliation and planarization by air calcination. In addition, the bandgap of g-C 3 N 4 -Ar/Air was slightly shrunk from 2.82 eV (pristine g-C 3 N 4 ) to 2.79 eV, and the CB was significantly upshifted from −0.44 eV (pristine g-C 3 N 4 ) to −0.81 eV, suggesting the powerful ability for donating the electrons for O 2 to form • O 2 − . Fukui index ( f – ) based on theoretical calculation indicated that the sites of SMT molecule with high values, i.e. , N9, C4 and C6, preferred to be attacked by • O 2 − and • OH, which is confirmed by the intermediates’ analysis. The tuning method for graphitic carbon nitride provides a simple approach to regulate the charge carrier lifetime then facilitate the utilization efficiency of solar light, which exhibits great potential in efficient removal of emerging organic contaminants from wastewater. Modified graphitic carbon nitride (g-C3N4-Ar/Air) was synthesized via a facial post-calcination method and exhibited efficiently photocatalytic activity for SMT removal due to the tune of band structure.

Adsorption and catalytic degradation of organic contaminants by biochar: Overlooked role of biochar’s particle size

Biochar (BC) is considered as a promising adsorbent and/or catalyst for the removal of organic contaminants. However, the relationship between the particle size of BC and its adsorption/catalysis performance is largely unclear. We therefore investigated the influence of particle size on the performance of BC pyrolyzed at 300–900 °C in trichloroethylene (TCE) adsorption and persulfate (PS) activation for sulfamethazine (SMT) degradation. The results showed that high-temperature pyrolyzed BC (BC900) presented superior adsorption capacity for TCE and excellent catalytic activity for PS activation to degrade SMT. Compared to 150–250 µm, 75–150 µm and pristine BC900, 0–75 µm BC900 showed the highest TCE adsorption efficiency, which increased by 19.5–62.3%. Similarly, SMT removal by BC900/PS systems also increased from 24.2% to 98.3% with decreasing BC particle size. However, the catalytic activity of BC after grinding was not significantly improved as expected, indicating the properties of biochar was not only controlled by size effect. Characterization measurements proved that small-sized BC tended to have larger specific surface area, more micropores, higher conductivity, rich graphitic domains and surface redox-active functional groups, thus resulting in an enhanced adsorption and catalytic ability of BC.

Signal-on electrochemical aptasensor for sensitive detection of sulfamethazine based on carbon quantum dots/tungsten disulfide nanocomposites

In this paper, a novel electroactive material named as carbon quantum dots-tungsten disulfide nanocomposite (CQDs-WS2) was prepared via a facile self-assembly method. Based on CQDs-WS2 modified glassy carbon electrode (CQDs-WS2/GCE), a label-free electrochemical aptasensing strategy was proposed to sensitively determine sulfamethazine (SMZ). Cationic polyethyleneimine (PEI) were employed to form complexes with negatively charged SMZ-binding aptamers immobilized on CQDs-WS2/GCE by amidation reaction, which decreased the adsorption capacity of [Ru(NH3)6]3+ to aptamers. When SMZ existed, the change of aptamer conformation due to the formation of SMZ/aptamer complex would lead to decrease in adsorption amount of PEI. More adsorbed [Ru(NH3)6]3+ on aptamer can produce enhanced reduction current. On the basis of CQDs-WS2 as electroactive materials, aptamer as a recognition receptor, PEI as electrostatic adsorbent of aptamer, and [Ru(NH3)6]3+ as an electroactive indicator, a signal-on electrochemical aptasensor was constructed for detection of SMZ with high sensitivity. The SMZ aptasensor displayed wide linear response in the 10 pM to 1.0 µM concentration range and a low detection limit of 4.0 pM. The method can be applied to quantitation analysis of antibiotic residue in food and environmental samples.

Degradation of antibiotics, organic matters and ammonia during secondary wastewater treatment using boron-doped diamond electro-oxidation combined with ceramic ultrafiltration

In this study, a BDD electrolytic oxidation-ceramic membrane ultrafiltration (EO-CM) system for the removals of antibiotics, organic matters and ammonia in wastewater was evaluated. Sulfamethazine (SMZ) was degraded following a pseudo first-order kinetics. The removal rate of SMZ improved with the increase of electro-oxidation time (0–60 min) and current density (5–30 mA/cm2). During the BDD electro-oxidation process, H2O2 and hydroxyl radicals (•OH) were generated which were detected by N, N-diethyl-p-phenylenediamine (DPD) method and electron paramagnetic resonance spectroscopy (EPR), respectively. Chemical oxygen demand (COD) was able to be removed by EO and CM processes, in which proteins and humic acids were regarded as the main removed components measured using excitation-emission matrix (EEM) technique. Moreover, BDD electro-oxidation pretreatment could make the CM process maintain a high water flux and significantly control the membrane fouling and relieve transmembrane pollution. In addition, the removal of ammonia was enhanced with the increase of chloride ions (Cl−) in wastewater during EO process due to the generation of active chlorine (i.e., ClO−, HClO, or Cl2) from the oxidation of Cl−. Chloramine and nitrogen were produced in the oxidation of ammonia by active chlorine. Overall, the results of this study suggest that BDD EO-CM system is a promising process for removing antibiotics, organic matters and ammonia.

Efficient degradation of sulfamethazine via activation of percarbonate by chalcopyrite

In this work, the novel application of chalcopyrite (CuFeS2) for sodium percarbonate (SPC) activation towards sulfamethazine (SMT) degradation was explored. Several key influencing factors like SPC concentration, CuFeS2 dosage, reaction temperature, pH value, anions, and humic acid (HA) were investigated. Experimental results indicated that SMT could be effectively degraded in the neutral reaction media by CuFeS2/SPC process (86.4%, 0.054 min−1 at pH = 7.1). The mechanism of SPC activation by CuFeS2 was elucidated, which was discovered to be a multiple reactive oxygen species (multi-ROS) process with the coexistence of hydroxyl radical (•OH), carbonate radical (CO3•−), superoxide radical (O2•−), and singlet oxygen (1O2), as evidenced by quenching experiments and electron spin resonance (ESR) tests. The generated •OH via the traditional heterogeneous Fenton-like process would not only react with carbonate ions to yield other ROS but also involve in SMT degradation. The abundant surface-bound Fe(II) was deemed to be the dominant catalytic active sites for SPC activation. Meanwhile, it was verified that the reductive sulfur species, the interaction between Cu(I) and Fe(III) as well as the available O2•− derived from the activation of molecular oxygen and the conversion of •OH favored the regeneration of Fe(II) on CuFeS2 surface. Furthermore, the degradation intermediates of SMT and their toxicities were evaluated. This study presents a novel strategy by integrating transition metal sulfides with percarbonate for antibiotic-contaminated water treatment.

Optimization of electrochemical activation of persulfate by BDD electrodes for rapid removal of sulfamethazine

Boron-doped diamond electrodes have been employed for the removal of sulfamethazine (SMZ) from water by electrochemical activation of persulfate (EO/BDD-PS). A set of experiments with a central composite design (CCD) was conducted to optimize the operating parameters such as persulfate dose, solution pH, and current density by response surface methodology (RSM). The experimental results indicated a rapid degradation of SMZ even at high initial concentrations. For instance, complete degradation of 50 mg L−1 of SMZ was attained after 15 min at the optimum operating conditions (persulfate loading = 0.40 g L−1, pH = 4, and current density = 21 mA cm−2). The oxidation mechanism of EO/BDD-PS process was studied based on the reactive oxidant species (ROS) revealing that both (OH) and ▪ contributed to the degradation of SMZ in the EO/BDD-PS system. Furthermore, the oxidation pathway has been proposed by the suspect screening and tandem mass spectrometry analysis. The performance of EO/BDD-PS showed faster SMZ degradation than electro-Fenton and anodic oxidation processes using the same BDD electrochemical reactor under the same conditions. Furthermore, we provided a cost estimation study revealing that a full-scale application of the EO/BDD-PS system for the treatment of similar contaminated water costs about $2.23 m-3.

Hydrophilic crosslinking agent-incorporated magnetic imprinted materials with enhanced selectivity for sulfamethazine adsorption

In this study, magnetic molecularly imprinted polymers (MMIPs) with enhanced selectivity were synthesized using sulfamethazine (SMZ) as template molecule and hydrophilic triethylene glycol dimethacrylate as cross-linker. Compared with that of imprinted polymers (MMIPs@EGDMA) prepared with commonly used ethylene glycol dimethacrylate, MMIPs with increased hydrophilicity could achieve efficient adsorption and preferred binding ability for template SMZ (selectivity factor increased from 0.9 of MMIPs@EGDMA to 1.9) in the presence of structural analogues with significant similarities (i.e. sulfamonomethoxine). Under the optimal extraction conditions, the developed MMIPs-MSPE-HPLC-DAD method showed wide linear range (1.6–250 μg/L), low detection limit (0.44 μg/L) and satisfactory precision (RSD ＜ 7%). The proposed strategy offers a potential and simple way to obtain imprinted polymers with high recognition capability, providing a perspective method in the accurate determination of SMZ in environmental water.

Effect of calcium peroxide pretreatment on the remediation of sulfonamide antibiotics (SMs) by Chlorella sp.

This study investigated the effect of CaO2 pretreatment on sulfonamide antibiotics (SMs) remediation by Chlorella sp. Results showed that a CaO2 dose ranging from 0.05 to 0.1 g/g biomass was the best and led to higher SMs removal efficacy 5–10% higher than the control. The contributions made by cometabolism and CaO2 in SMs remediation were very similar. Bioassimilation could remove 24% of sulfadiazine (SDZ) and sulfamethazine (SMZ), and accounted for 38% of sulfamethoxazole (SMX) remediation. Pretreatment by CaO2 wielded a positive effect on microalgae. The extracellular polymeric substances (EPS) level of the CaO2 pretreatment microalgae was three times higher when subjected to non-pretreatment. For the long-term, pretreatment microalgae removed SMs 10–20% more than the non-pretreatment microalgae. Protein fractions of EPS in continuous operation produced up to 90 mg/L for cometabolism. For bioassimilation, SMX intensity of the pretreatment samples was 160-fold less than the non-treatment one. It indicated the CaO2 pretreatment has enhanced the biochemical function of the intracellular environment of microalgae. Peroxidase enzyme involved positively in the cometabolism and degradation of SMs to several metabolites including ring cleavage, hydroxylation and pterin-related conjugation.