紫外联用高级氧化技术降解氯霉素试验研究

为了实现紫外高级氧化技术在实际水处理中去除抗生素的应用,以氯霉素(CAP)为研究对象,对比了静态试验中紫外技术,连续流下单独紫外技术、紫外高级氧化技术(UV/H2O2、UV/PS)对氯霉素的去除效能.进一步分析了连续流下紫外光强、紫外光波长、停留时间、氧化剂投加量、氯霉素初始浓度和原水水质等因素对去除效果的影响.研究发...     

气相色谱-负化学源质谱法测定蜂蜜和奶粉中氯霉素残留量

研究了蜂蜜和奶粉中氯霉素残留量的气相色谱——质谱分析方法。将样品溶于水,其中的氯霉素残留物用乙酸乙酯提取,提取物用C18固相萃取柱净化,净化液再用乙酸乙酯反提取,经N,O-双(三甲基硅烷基)三氟乙酰胺(BSTFA) 1％三甲基氯硅烷(TMCS)衍生后,用配有负化学源质谱检测器的气相色谱仪测定。当添加水平为0．1～10μg/kg时,回收率为80．4％～95．3％,相对标准偏差为9．3％～18．1％。     

Theoretical and experimental research on self‐assembly system of molecularly imprinted polymers formed via chloramphenicol and methacrylic acid

Chloramphenicol was chosen as the imprinting molecule and the methacrylic acid was chosen as the functional monomer to prepare molecularly imprinted polymers. Ethylene glycol dimethacrylate, pentaerythritol triacrylate, and trimethylolpropane trimethylacrylate were used as the cross‐linking agents, respectively. The interaction processes between chloramphenicol and methacrylic acid were simulated by using the ωB97XD/6‐31G (d,p) method. The self‐assembled configuration, bonding sites, binding number, binding energy, and interaction principle of stable complex formed by chloramphenicol and methacrylic acid with different molar ratios have been studied. The selectivity of the most stable complex formed from chloramphenicol and methacrylic acid was discussed with the thiamphenicol and florfenicol as the analogues of chloramphenicol. The results showed that chloramphenicol and methacrylic acid were interacted through the hydrogen bonds. When the molar ratio was 1:10 and pentaerythritol triacrylate as the cross‐linking agent, the ordered complex formed by chloramphenicol and methacrylic acid has the largest amount of hydrogen bonds and the lowest binding energy. Scatchard analysis showed that the maximum apparent adsorption capacity was 173.3 mg/g (0.536 mol/g), and the selection factor of florfenicol was the largest. This study provides a reliable theoretical and experimental basis for the design, preparation, and characterization of chloramphenicol molecularly imprinted polymers.     

压电磁性表面分子印迹传感器对氯霉素的检测

将磁性表面分子印迹技术与压电传感器结合,研究了一种氯霉素的检测的新方法。合成的氯霉素磁性表面分子印迹聚合物是以磁性纳米颗粒为载体,以甲基丙烯酸为功能单体进行聚合反应。磁性分子印迹聚合物的形态学功能、吸附作用、识别性能等是通过紫外分光光度计、红外光谱分析仪及透射电子显微镜等进行检测的。同时,设计压电磁性表面分子印迹传感器,即将磁性表面分子印迹聚合物修饰在压电传感器的敏感元件上。用所制备的压电磁性表面分子印迹传感器对氯霉素进行检测。实验结果表明该传感器对氯霉素有很好的结合能力和高灵敏性。即氯霉素的检测限为6μg/L,检测时间为10 min。     

Application of Thermogravimetry in the Quality Control of Chloramphenicol Tablets

The stability and thermal behaviour of chloramphenicol and various of its mixtures were investigated. The thermogravimetric and stability constant results showed that the chloramphenicol base is thermally more stable than the tablet in the studied formulation. The reduction in stability was attributed to the presence of starch in the formulation. The thermal decompositions of the chloramphenicol base and the tablet obey first-order kinetics. This revised version was published online in August 2006 with corrections to the Cover Date.     

Electrochemical Aptasensor Based on Au Nanoparticles Decorated Porous Carbon Derived from Metal-Organic Frameworks for Ultrasensitive Detection of Chloramphenicol

A facile and sensitive electrochemical aptamer sensor (aptasensor) based on Au nanoparticles-decorated porous carbon (AuNPs/PC) composite was developed for the efficient determination of the antibiotic drug chloramphenicol (CAP). AuNPs modified metal-organic framework (AuNPs/ZIF-8) is applied as a precursor to synthesize the porous carbon with homogeneous AuNPs distribution through a direct carbonization step under nitrogen atmosphere. The as-synthesized AuNPs/PC exhibits high surface area and improved conductivity. Moreover, the loading AuNPs could enhance the attachment of the aptamers on the surface of electrode through the Au–S bond. When added to CAP, poorly conductive aptamer-CAP complexes are formed on the sensor surface, which increases the hindrance to electron transfer resulting in a decrease in electrochemical signal. Based on this mechanism, the developed CAP aptasensor represents a wide linear detection range of 0.1 pM to 100 nM with a low detection limit of 0.03 pM (S/N = 3). In addition, the proposed aptasensor was employed for the analysis of CAP in honey samples and provided satisfactory recovery.     

海洋病原细菌Enterobacter sp. EM28-2共存氯霉素乙酰化和磷酸化灭活机制

报道1例氯霉素耐药性病原菌中共存乙酰化和磷酸化灭活机制。海洋病原菌Enterobactersp.EM28-2(Cmr,M IC=128μg/mL)接种在含25μg/mL标准品D-(-)-氯霉素LB培养基中培养24h后,可同时生成乙酰化和磷酸化氯霉素。LC-MS分析检测出新生成3类指纹峰:①[M C2H2O-H]-(m/z 363.0,364.9),对应氯霉素C1位羟基的乙酰化产物;②[M PO3-H]-(m/z 398.9,400.9,402.9),对应氯霉素C3位羟基的磷酸化产物;③[M C4H4O2-H]-(m/z 408.7,410.7),对应氯霉素C1位和C3位羟基的乙酰化产物。     

Asymmetric reduction of aromatic ketones catalyzed by using (αs, 4s)-2-dichloromethyl-4, 5-dihydro-α-(4-nitrophenyl)-4-oxazolemethanol-borane complex

Chiral oxazoborolidine borane complex was prepared from (αs, 4s)-2-dichloromethyl-4, 5-dihydro-α-(4-nitrophenyl)-4-oxazolemethanol with Borane in THF. The borane modified by chiral oxazoborolidine enantioselectively reduced aromatic ketones to second-alcohol with about 95% yield and medium optical yields. In the end of article, results are discussed and reduction mechanism is shown which proves the resulting major isomers fit very well. Foundation item: Sopported by DSM Andeno of Holland Biography: Shi Yu (1975-), Master candidate, research direction: asymmetric, synthesis.     

高效液相色谱-串联质谱法测定蜂胶及以其为原料的保健食品中的氯霉素

建立了同时适用于蜂胶及以其为原料的保健食品中氯霉素残留的检测方法。样品中的蜂胶经乙醇溶解,以4%（质量分数）乙酸铅溶液沉淀具有邻二酚羟基结构的黄酮类成分,在碱性条件下进一步去除不含此结构的黄酮类干扰物,并以甲基叔丁基醚为提取溶剂,有效减少样品中极性干扰物和保健食品辅料（如聚乙二醇、甘油等）的共提取。试样溶液经HPLC-MS/MS测定,内标法定量。线性范围为0.20~50.0 μg/L,相关系数为0.9998;方法检出限为0.03 μg/kg,定量限为0.1 μg/kg;不同基质的回收率为86.0%~114.4%,相对标准偏差为0.3%~4.9%。该方法通用性强,操作简便,灵敏度高,抗干扰能力强,推广应用前景良好。     

Simple,efficient, and eco‐friendly sample preparation for simultaneous determination of paracetamol and chloramphenicol in meat

We have developed and validated a simple, eco‐friendly, and reliable method to simultaneously determine paracetamol and chloramphenicol in meat with ultra performance liquid chromatography and tandem mass spectrometry. The samples were firstly extracted with ethylenediaminetetraacetic acid–McIlvaine's buffer and then purified by solid‐phase extraction by using a novel core‐shell polyaniline/polyacrylonitrile nanofibers mat. Compared with existing methods for the two analytes, the proposed method was simplified greatly with much fewer sample preparation steps, consumed much less time (< 2 min per sample) and organic solvent (0.7 mL per sample). Low detection levels (0.15–0.20 µg/kg for paracetamol, 0.01 µg/kg for chloramphenicol) with good precision and recoveries of the target compounds were obtained. The proposed method was applied to determine the residual paracetamol and chloramphenicol in pork, chicken, and beef samples, and the test results were consistent with those using the Chinese national standard methods, which demonstrates the reliability and practicality of the new method.