The selective removal of Fe particles from carbonized Fe-MOFs presents an intriguing strategy for developing efficient peroxydisulfate (PDS) activators. It is commonly accepted that their outstanding performance is largely attributed to the high specific surface area/pore volume. However, our investigation into the structure-function relationship of these materials has revealed new insights. In this study, a highly dispersed single-atom Fe and Fe3O4 clusters anchored hierarchical-pore carbon (CM88-H) was obtained via post-acid treatment of carbonized MIL-88B (CM88). Various characterizations were comparatively conducted to highlight the beneficial effects of iron dissolution. The CM88-H/PDS system achieved a notable BPA degradation efficiency, with a reaction rate of 0.323 min-1, which is 3.94 times higher than that of the CM88/PDS system. DFT calculations indicate that the Fe3O4 clusters optimize the charge distribution around single-atom Fe, promoting favorable PDS adsorption and facilitating a higher oxidation state of CM88-H. As a result, BPA can be completely degraded within 10 min with 0.1 g L-1 CM88-H and 0.05 g L-1 PDS via both radical and non-radical pathways. The CM88-H/PDS/BPA system performs effectively under various conditions, with a general reduction in toxicity. Furthermore, the CM88-H/ PDS system shows broad oxidation activity towards BPA substitutes and pollutants with high ionization potential (IP). Notably, the CM88-H sponge-based fixed-bed catalytic reactor demonstrated satisfactory BPA degradation, highlighting the promising application of CM88-H in water purification. This study provides a sustainable solution for water treatment and accelerates the practical application of powdered nanocatalysts to improve water quality.

A QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method was developed to provide good analytical results for teicoplanin (TEC) and ramoplanin (RAM) residues in aquatic products. The analytes was extraction from aquatic product samples using chitosan in the QuEChERS procedure. Compared to conventional adsorbents, chitosan has a relatively good purification ability for the targets. The matrix effects of aquatic products, such as crucian carp, carp, silver carp, tilapia, mandarin fish, turbot, shrimp, sea cucumber and so on, were evaluated by high performance liquid chromatography coupled to triple-quadrupole tandem mass spectrometry. Throughout the validation experiments, the limits of detections and quantifications ranged from 0.4 similar to 0.8 mu g kg(-1) and 1.0 similar to 3.0 mu g kg(-1), respectively. Calibration curves showed correlation coefficient values higher than 0.998 in range between 1 and 100 mu g kg(-1). The recoveries ranged from 89.8 % to 110.0 % with relative standard deviation less than 7.2 % in nine typical aquatic products. The method shows low matrix effect (-18.5 %similar to-2.6 %) for all targets in different aquatic products. The proposed methods proved to be reliable, effective and enables rapid determination of large batch samples, indicating its good applicability for detection and monitoring of TEC and RAM residues in aquatic products.

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 methodologymodified 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 mu g/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.

Metalaxyl is widely used as a racemic mixture to control various plant and aquatic animal diseases caused by fungal infection. It has been proved that the two enantiomers of metalaxyl have significant differences in activity and toxicity, while little is known about the pharmacokinetics and residual elimination of the individual enantiomers of metalaxyl in aquatic animals. In this study, a simple, sensitive and reliable chiral liquid chromatography-tandem mass spectrometry method was established for the determination of metalaxyl and its metabolite metalaxyl acid enantiomers, which was applied to study the stereoselective pharmacokinetics and residue elimination of individual enantiomers in snakehead (Channa argus). The snakehead was bath administered with the racemic metalaxyl and the highly active enantiomeric R-metalaxyl, respectively. The results showed that the elimination of metalaxyl in the plasma and tissues of snakehead was enantioselective. The concentration of metalaxyl in tissues was kidney > liver > muscle, and preferential degradation of the R-metalaxyl enantiomer was observed in three tissues. However, no transformation between metalaxyl enantiomers was observed in snakehead plasma and tissues when R-metalaxyl enantiomer was administered. In addition, the distribution of metalaxyl acid enantiomers in tissues is closely related to the parent compound metalaxyl, and S-metalaxyl acid was only observed in the kidney and slowly eliminated. The highest concentrations of both metalaxyl and metalaxyl acid were observed in the kidney, suggesting that kidney is the major site of metalaxyl metabolism in snakehead. Given that the highly active R-metalaxyl has a shorter half-life and does not undergo transformation between enantiomers in snakehead, it may be a better choice to use R-metalaxyl instead of racemic metalaxyl in clinical practice. The results are helpful to understand the detailed fate of metalaxyl enantiomers and should be considered in future aquaculture, environmental pollution risk and food safety evaluations.

A Quick, Easy, Cheap, Effective, Rugged and Safe pre-treatment method (QuEChERS) was established to evaluate the risk of tetracycline residues in the muscle of Channa argus. The Box-Behnken design (BBD) response surface optimization method was used to optimize the extraction and purification conditions. The samples were extracted with 10 mL acetonitrile (containing 1% formic acid) and 2 mL 0.1 mol/L Na2EDTA-Mcllvaine buffer solution, and the extracts were purified by 150 mg primary secondary amine（PSA）and 200 mg C18, and detected with Ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The result showed that the calibration curve was linear in the range of 0.50~100 ng/mL, with high correlation coefficients (r≥0.999). The limits of detection (LOD) and quantification (LOQ) were 0.25～0.75 μg/kg and 0.84～2.00 μg/kg, respectively. The average recoveries of tetracycline, oxytetracycline, chlortetracycline and doxycycline at three different spiked levels in the muscle of Channa argus were 89.5%～118%, with relative standard deviations (RSDs) of 1.11%～8.88%. This method is simple, sensitive and accurate, and can be used for the rapid quantitative determination of tetracyclines in Channa argus.

•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.

该研究制备了铁基金属有机骨架MIL-88B(Fe)衍生磁性多孔碳材料Fe@Fe3C-C,并将其用于水中双酚A(BPA)的高效吸附.采用X射线衍射、扫描电镜和比表面积及孔径分析等手段对材料的晶体结构、形貌和比表面积进行表征.结果表明,在高温作用下,MIL-88B(Fe)转化成Fe、Fe3C共掺杂碳材料(Fe@Fe3C-C).Fe@Fe3C-C呈具有层次的炸裂状薄片结构且表面较为粗糙,比表面积为280.48 m2/g,与MIL-88B(Fe)相比增加了17倍.吸附实验表明,与MIL-88B(Fe)相比,高温煅烧(≥600℃)可以明显提升吸附性能.0.5 g/L的Fe@Fe3C-C在10 min内对10 mg/L的BPA去除率高达95％.材料具有较广的pH值适用范围(pH 2.0～10.0)和较强的抗无机盐离子(100 mmol/L)干扰能力,并能够用于高盐环境下的BPA吸附.拟二级动力学模型符合BPA在Fe@Fe3C-C上的吸附动力学曲线,吸附过程符合Langmuir模型.循环实验表明,Fe@Fe3C-C易于从水体中回收,且具有良好的可再生性能.上述研究结果表明Fe@Fe3C-C对水中BPA的去除具有较大的潜力.通过X射线光电子能谱、Zeta电位等表征探究吸附机理,结果显示Fe@Fe3C-C的主要作用机制为微孔填充、静电作用及π-π作用.

Enrofloxacin (ENR) is widely used in aquaculture practice, but little is known about its pharmacokinetic, withdrawal period and dietary risk in fish via bath administration. The purpose of this study was to provide data support for the use of ENR bath therapy in the northern snakehead (Channa argus). The pilot study was carried out to evaluate the therapy concentrations of ENR in northern snakehead with immersion concentrations ranged from 5 to 40 mg/L for 6 h. Based on results of the pilot study, an ENR immersion concentration of 20 mg/L was used for the formal experiment. At this dose, the peak concentrations of ENR in plasma, muscle plus skin, liver and kidney were 4.85, 4.55, 3.87 and 7.42 μg/mL (or g), respectively. According to the AUC0-∞ values, the distribution of ENR in northern snakehead followed the order of kidney > plasma > liver > muscle + skin. The elimination of ENR in northern snakehead was very slow, the half-lives (T1/2λz ) were up to 90.31, 85.5, 104.56 and 120.9 h in plasma, muscle plus skin, liver and kidney, respectively. Ciprofloxacin (CIP) was not detected in any samples in the pilot study and was only occasionally detected in muscle plus skin and liver samples in formal experiment. Based on the calculated PK/PD index AUC/MIC and Cmax /MIC, the current bath treatment regimen will have a good therapeutic effect on infections caused by bacteria with MIC below 0.6 μg/mL. The dietary risk assessment suggested that there was a dietary risk (Hazard Quotients > 10%) until day 6 after bath treatment. It is mandatory for ENR to maintain a withdrawal period of at least 450°C-day in northern snakehead after bath treatment ceased.

In this study, a multi-residue determination method of QuECHERS combined with UHPLC-MS/MS was developed to determine nine β-lactam antibiotics (penicillin G, amoxicillin, ampicillin, cephalexin, cefquinome, ceftiofur, cefazolin, cephapirin, cefuroxime) in aquaculture products. All the nine β-lactam antibiotics exhibited excellent linearity within the range of 2.0–200 ng/mL (cefuroxime: 5.0–200 ng/mL, r greater than 0.999), while the limits of detection (LODs) and quantification (LOQs) were 2.0–5.0 μg/kg and 5.0–10.0 μg/kg, respectively. The recoveries of this method in five aquaculture products (Penaeus Orientalis, Cyprinus Carpio, Channa Argus, Aristichthys Nobilis, and Ctenopharyngodon Idella) ranged from 85.4% to 113.3% and the intra-day and inter-day precisions (%RSDs) were less than 15%. The results suggested the feasibility of this method as a rapid, simple, and accurate approach for determining the residues of the β-lactam antibiotics in aquaculture products.

本研究以QuEChERS作为样品前处理手段,建立了测定水产品饲料中地西泮残留的气相色谱-质谱法(GC-MS).样品经纯水和乙腈提取后加入无水硫酸钠除水及氯化钠盐析,提取液经吸附剂中性氧化铝、PSA、纳米二氧化锆结合GCB粉净化后上机检测,内标法定量.结果显示:地西泮在5～500μg/L质量浓度范围内线性关系良好,相关系数为0.9992,对配合饲料、浓缩饲料及饲料添加剂开展3个水平加标回收实验(0.15、0.25、0.50 mg/kg),方法加标回收率为86.3％ ～104.5％,相对标准偏差为1.4％ ～7.8％,地西泮的检出限为0.05 mg/kg,定量限为0.20 mg/kg,方法检出限远低于标准"NY/T 934—2005"的方法检出限1.00 mg/kg.该法具有前处理过程简单、快速、灵敏度高的优点,适合各种水产饲料中地西泮残留的测定.

采用QuEChERS前处理技术,建立了鱼肉中6种替考拉宁组分的高效液相色谱-串联质谱检测方法.搅碎均匀的鱼肉样品经乙腈-10％三氯乙酸(6:4,体积比)提取,100 mg乙二胺-N-丙基硅烷(PSA)净化后,使用Agilent SB C18(2.1 mm×100 mm,1.8μm)色谱柱分离,以0.1％甲酸乙腈和0.1％甲酸为流动相进行梯度洗脱,采用电喷雾电离正离子(ESI+),多反应监测模式(MRM)进行检测,内标法定量.考察了提取溶剂种类与体积、吸附剂种类与用量对目标化合物回收率的影响.评价了6种目标物在不同鱼肉基质中的基质效应.在优化条件下,6种替考拉宁组分在4 min内得到良好分离.目标物在各自浓度范围内线性良好,相关系数(r2)均不小于0.998;在5.0、10.0、25.0μg/kg 3个加标水平下,各组分的回收率为84.3％～93.3％,日内相对标准偏差和日间相对标准偏差(n=6)分别不大于7.0％和6.2％,方法的检出限和定量下限分别为0.5～2.0μg/kg和2.0～5.0μg/kg.采用该方法对采集的9种40个鱼肉样品进行检测,所有样品均未检出替考拉宁组分.该方法简单、灵敏、准确、可靠,可用于鱼肉中6种替考拉宁组分的定量分析.

利用固相萃取(SPE)/超高效液相色谱-串联质谱(UPLC-MS/MS)建立了稻渔水体中氟虫腈及其代谢物(氟甲腈、氟虫腈砜和氟虫腈亚砜)的分析方法.根据目标物的化学性质及稻渔水样的基质情况,筛选出适用于稻渔水样预处理的滤膜及稻渔水体中目标物的萃取方法,并对固相萃取条件、氮吹温度等参数进行优化.稻渔水样经玻璃纤维滤纸过滤后,由Supelco ENVI-18固相萃取柱富集、净化,采用SB-C18柱(2.1 mm×100 mm,1.8μm)进行分离,在电喷雾电离源负离子模式下进行检测,外标法定量.结果显示:目标物在0.5～100 ng/mL范围内线性关系良好,相关系数(r2)大于0.998,检出限为0.5 ng/L,定量下限为1.5 ng/L;在2、5、50 ng/L加标水平下的回收率为81.6％～105％,相对标准偏差为3.5％～7.0％.该方法操作简便、灵敏、高效、性价比高,可用于稻渔水体中氟虫腈及其代谢物的同时测定.

Pyrethroids pesticides (PPs) are the widely adopted synthetic pesticides for agriculture and fishery. The frequent use of these pesticides leads to the accumulation of residues in the freshwater environments in China, subsequently affecting aquatic organisms and ecosystems. However, there are few reports on the toxicological and risk assessment of aquaculture aquatic products. In this study, the uptake, depuration kinetics and potential risk to human health and ecology of fenpropathrin, cypermethrin, fenvalerate, and deltamethrin were assessed using tilapia. The results indicated that four PPs were readily accumulated by tilapia. The bioconcentration factors (BCF) of the PPs in plasma and muscle were between 71.3 and 2112.1 L/kg and 23.9–295.3 L/kg, respectively. The half-lives (t1/2) of muscle and plasma were 2.90–9.20 d and 2.57–8.15 d. The risks of PPs residues in the muscle of tilapia and exposed water were evaluated by hazard quotient (HQ) and risk quotient (RQ). Although PPs residues in tilapia had a low dietary risk to human health, the residues in the exposed water had a high ecological risk to fish, daphnia, and green algae. Therefore, assessing the PPs content in freshwater aquaculture and monitoring their dosages and frequencies are highly necessitated to avoid their adverse effect on the aquaculture environment.

It is great challenge to design a simple approach to prepare Co-based N-doped carbon catalysts with high activity and minimum impact to the environment. Here, a novel carbonized poly(dopamine)-coated cobalt nanocomposite (CPDA@Co0) was synthesized via a simple and "zero-organic solvents" approach and employed to activate persulfate (PS) for sulfamethoxazole (SMX) degradation. The CPDA@Co0/PS system exhibited outstanding performance on SMX degradation over a wide pH range (3.0-8.5), and facilitated by acidic conditions and Cl-. For fair comparison, CPDA@Co0 under slightly acidic pH exhibited a much higher rate constant (0.121 min-1) than many reported catalysts. A direct electron-transfer pathway played a leading role in the oxidation, while adsorption of SMX on the surface of CPDA@Co0 might be the determining step. Since the synergistic effect between adsorption and catalysis, 10 mg/L SMX could be completely removed within 25 min, which provided a new strategy for removing organic pollutants from wastewater. Besides, the special core-shell structure could efficiently protect inner Co0 core from leaching. CPDA@Co0 could be easily separated via a permanent magnet and reused at least 5 times. This study might inspire others to develop effective and green PS activation processes for application in SMX treatment.

以QuEChERS作为样品前处理手段,建立测定水产品中扑草净残留的气相色谱-质谱法(GC-MS).样品以乙腈-二氯甲烷(V∶V=8∶ 2)混合溶液提取,提取液经吸附剂中性氧化铝、N-丙基乙二胺(PSA)、纳米二氧化锆结合石墨化炭黑(GCB)净化后上机检测,内标法定量.结果显示,扑草净质量浓度介于5～200 μg·L-1线性关系良好,相关系数(R2)为0.999 9.对草鱼(Ctenopharyngodon idellus)、鳜(Siniperca chuatsi)、中国对虾(Penaeus chinensis)、海参(Holothuria sp.)和文蛤(Meretrix meretrix)进行4个水平的加标回收实验(10、20、40和200 μg·kg-1),方法的加标回收率为85.8％～111.8％,相对标准偏差为1.2％～8.8％,满足GB/T 27404-2008《实验室质量控制规范食品理化检测》中实验室质量控制规范.扑草净的检出限(LOD,S/N≥3)和定量限(LOQ,S/N≥10)分别为5和10μg·kg-1.该方法简单、快速、灵敏、净化效果好,能满足水产品中扑草净残留的检测需求.