高效液相色谱法测定动物组织中磺胺类残留量

磺胺类合成抗菌药是一类抑制核酸合成的抗菌药，可分为全身应用、肠道应用和局部外用等3类。磺胺类药物作为预防与治疗用药而广泛地用于食用动物中。但有文献报道该类药物可能使小鼠致癌。同时，由于该类药品可残留在动物组织中，食用含有磺胺类药物残留的动物源性食品，可引起过敏、尿和造血紊乱等不良反应。目前中国、欧盟、美国、日本、韩国等国家均将磺胺类药物列为动物饲养过程中限制使用的药物，其最大残余限量一般为50～100μg／kg。本实验采用样品加入乙腈提取后，用乙腈饱和的正己烷去除脂肪和杂质，通过优化色谱条件，进行7种磺胺类药物多残留的同时测定。结果表明，本方法简便，快速，结果准确，适合大批量样品的测定。     

液相色谱-串联三重四极杆质谱对牛奶中10种磺胺类药物残留的同时测定

磺胺类药物是畜牧和牛乳生产中应用最广泛的治疗动物细菌感染的药物.牛奶中残留此类药物能引起肾损害,特别是乙酰化磺胺在尿中溶解度低,析出结晶质对肾脏损害更大.因此,及时寻求简便、快速、准确、灵敏度高的牛奶中磺胺类药物残留的检测方法才能满足日趋严格的残留限量要求,保障人们饮用牛奶的卫生和安全.     

磺胺类药物化学研究新进展

磺胺是应用最早的一类化学合成抗菌药,在治疗感染性疾病中起着重要作用,因此许多研究致力于磺胺类化合物的深入开发.母体结构对氨基苯磺酰胺经化学结构修饰后呈现广泛的生物活性,显示出巨大的药用潜力和开发价值,相关研究异常活跃.结合本课题组研究,参考国内外近5年文献,本文系统地综述了磺胺母体结构不同部位的化学结构修饰及其衍生物,包括其金属超分子络合物在抗微生物、抗癌、抗寄生虫、消炎镇痛、抗惊厥、抗青光眼、抗糖尿病、抗癫痫及相关神经性疾病和利尿药等药用研发新情况,并展望了其发展趋势.希望为广谱性、高活性和低毒性磺胺类新药分子的合理设计提供指导,为开拓磺胺类化合物的用途提供新思路.     

分散液液微萃取-高效液相色谱法测定水中磺胺类药物残留

建立了分散液液微萃取-高效液相色谱法测定水样中氨苯磺胺、磺胺嘧啶,磺胺二甲基嘧啶3种磺胺药物残留的检测方法。对萃取剂、分散剂的种类和体积、pH、盐浓度等影响萃取效率的因素进行了优化。在最优的萃取条件下,3种抗菌药的测定线性范围为1~1000μg/L,r≥0.9997,检出限为0.07~0.25μg/L(S/N=3)。应用于5种不同水样中磺胺类抗菌药残留的分析,目标分析物的加标回收率在82.0%~104.0%之间,相对标准偏差小于5.9%。     

全自动固相萃取技术同时测定动物产品中9种磺胺药物残留

针对目前动物产品中兽药残留检测样品前处理繁琐的问题,应用全自动固相萃取技术对动物产品中9种磺胺类药物残留检测的样品前处理方法进行了系统的研究,对提取溶剂、固相萃取柱、淋洗液、洗脱溶剂及仪器分析条件进行了优化选择,建立了新型磺胺药物残留检测的全自动固相萃取净化方法.经不同检测单位验证,该方法的加标回收率为78.4%～107.8%,精密度为3.9%～11.0%检出限为0.010～0.020mg/kg,满足出口检测要求.     

动物源性食品中磺胺类药物残留的固相萃取-高效液相色谱法测定

研究了动物源性食品中磺胺嘧啶、磺胺二甲嘧啶、磺胺间甲氧嘧啶、磺胺喹啉药物残留的提取、净化和高效液相色谱分析条件 ,建立了高效液相色谱法同时测定动物源性食品中磺胺类药物残留的方法 ,该法检出限为0.010×10-6～0.020×10-6(w) ,添加回收率为71 %～83 %。     

高效液相色谱-荧光-紫外法测定动物肌肉组织中多类药物残留

建立了同时检测动物肌肉组织中9种喹诺酮类药物、7种磺胺类药物和甲氧苄啶的高效液相色谱检测方法.动物肌肉组织样品用磷酸盐缓冲液提取,HLB固相萃取柱净化,洗脱液用氮气吹至近干,磷酸盐缓冲液复溶,以甲酸水溶液-乙腈体系为流动相,梯度洗脱,荧光-紫外检测器串联测定.本方法的线性良好,相关系数r>0.9987;平均回收率为70.6%～103.4%,相对标准偏差为1.2%～11.4%; 荧光检测器测定喹诺酮类药物的检出限为0.04～0.4 μg/kg;紫外检测器测定磺胺类药物和甲氧苄啶的检出限为3.5 μg/kg.本方法具有简便、通用性强的特点,适用于动物肌肉组织中上述药物的常规残留检测.     

磁性固相萃取-高效液相色谱法测定牛奶中4种磺胺类药物

正磺胺类药物(SAs)是一种含有对氨基苯磺酰胺结构的化学合成药物,可用于预防和治疗细菌性疾病,并广泛应用于畜牧业。由于人们不合理使用,磺胺类药物经各种途径进入人体,从而危害了人类的健康~([1-3])。世界各国已经对磺胺类药物的残留危害相当重视,国际食品法典委员会(CAC)和欧美等许多国家也对磺胺类药物的残留量作了相关规定~([4-5])。     

免疫亲和柱净化/高效液相色谱法同时测定动物源性食品中16种磺胺类药物残留

建立了免疫亲和柱净化/高效液相色谱法(IAC/HPLC)同时测定动物源性食品中16种磺胺类药物残留的分析方法。样品经80%乙醇提取,稀释后用磺胺类药物免疫亲和柱净化,高效液相色谱法检测。以Agi-lent Eclipse XDB-C18为分离色谱柱,甲醇-磷酸盐缓冲液(pH 3.5)为流动相梯度洗脱,流速为1.0 mL/min,进样量为50μL,检测波长为270 nm,整个分析过程不超过42 min。实验结果表明,磺胺类药物在10～200μg/L范围内线性关系良好,相关系数均大于0.999。在20、50、100μg/kg的加标水平下,16种磺胺类药物的平均回收率为62%～104%,相对标准偏差为0.9%～6.6%,检出限(S/N=3)为4～10μg/kg。该方法简便快速、灵敏度高、溶剂用量少且环保,适用于动物源性食品中磺胺类药物残留的测定。     

超高效液相色谱-串联质谱法对奶粉中氯霉素残留的检测

氯霉素(chloramphenicol,CAP)是一种广谱抗生素,常用于动物各种传染性疾病的治疗,对多种病原菌有较强的抑制作用.在奶牛生产中,抗生素类药物的使用频率很高,尤其是治疗乳房炎、腹泻等疾病时,常常大剂量反复使用,从而在一段时间内造成奶及奶制品中的残留,形成"有抗奶",对人体造成危害.因此许多国家(包括中国)禁止在奶源动物身上使用氯霉素.     

Multi-wall carbon nanotubes with nitrogen-containing carbon coating

Polyaniline coating was deposited on the surface of multi-wall carbon nanotubes of Russian and Taiwanese origin in situ during the polymerization of aniline. The deposited polyaniline film was subsequently carbonized under an inert atmosphere at various temperatures to produce coaxial coating of the carbon nanotubes with nitrogen-containing carbon. The new materials were investigated by infrared and Raman spectroscopies, which demonstrated the conversion of the polyaniline coating to a carbonized structure. X-ray photoelectron spectroscopy proved that the carbonized overlayer contains nitrogen atoms in various covalent bonding states. Transmission electron microscopy confirmed the coaxial structure of the composites. The Brunauer-Emmett-Teller method was used to estimate the specific surface area, the highest being 272 m² g^?1. The conductivity of 0.9–16 S cm^?1 was measured by the four-point method, and it was only a little affected by the carbonization of the polyaniline coating.     

Porous carbon and carbon composite hollow spheres

In this communication, we propose a template approach toward synthesis of carbon hollow spheres by direct carbonization of highly crosslinked sulfonated polystyrene gel hollow spheres (sPS). The sulfonic acid group can facilitate carbonization. Moreover, the acid group can also induce a favorable growth of other materials within the sPS gel-forming carbon-based composite shell such as bi-continuous C/SiO₂ and their derivative ceramic SiC. Release of small molecules during polymers decomposition results porous shell.     

Adsorption of carbon dioxide on microporous carbon adsorbents

Adsorption isotherms of carbon dioxide on microporous carbon adsorbents prepared by activation with potassium sulfide in water vapor were measured. The measurements were carried out in the pressure interval from 1 Pa to 0.1 MPa at temperatures from 216.2 to 293.15 K. Based on the theory of volumetric filling of micropores, the main structural and energetic parameters of the microporous carbon adsorbents were calculated. The adsorption isosters of carbon dioxide were calculated from the adsorption isotherms in the same pressure and temperature ranges and approximated by linear dependences. The plots of the differential mole isosteric heats of adsorption vs amount adsorbed were constructed by using the adsorption isosters.     

Multifunctional molecular carbon materials--from fullerenes to carbon nanotubes

This critical review covers the timely topic of carbon nanostructures-fullerenes and carbon nanotubes-in combination with metalloporphyrins as integrative components for electron-donor-acceptor ensembles. These ensembles are typically probed in condensed media and at semi-transparent electrode surfaces. In particular, we will present a comprehensive survey of a variety of covalent (i.e., nanoconjugates) and non-covalent linkages (i.e., nanohybrids) to demonstrate how to govern/fine-tune the electronic interactions in the resulting electron-donor-acceptor ensembles. In the context of covalent bridges, different spacers will be discussed, which range from pure "insulators" (i.e., amide bonds, etc.) to sophisticated "molecular wires" (i.e., p-phenylenevinylene units, etc.). Furthermore, we will elucidate the fundamental impact that these vastly different spacers may exert on the rate, efficiency, and mechanism of short- and long-range electron transfer reactions. Additionally, a series of non-covalent motifs will be described: hydrogen bonding, complementary electrostatics, pi-pi stacking and metal coordination-to name a few. These motifs have been successfully employed by us and our collaborators en route towards novel architectures (i.e., linear structures, tubular structures, rotaxanes, catenanes, etc.) that exhibit unique and remarkable charge transfer features.     

甲烷在石墨化热解碳黑和活性炭上的吸附

为研究影响碳基吸附剂吸附超临界温度气体的主要因素,选择石墨化热解碳黑BP280和Ajax活性炭,分析超临界温度高压甲烷在其上的吸附平衡。应用容积法,在压力0~20.5 MPa、温度253 K~313 K测定甲烷的吸附平衡数据,并由等量吸附线标绘和亨利定律常数确定等量吸附热。引入通用吸附等温方程,再由方程的Langmuir标绘确定最大吸附容量,进而通过方程的线性化计算吸附平衡态中甲烷分子的作用能。结果表明,甲烷在两种吸附剂上的最大吸附容量均随温度而变化,并都小于液态甲烷的密度;甲烷在碳黑和活性炭上的等量吸附热分别为11.9 kJ/mol~12.5 kJ/mol和17.5 kJ/mol~22.5 kJ/mol,体现了两种吸附剂不同的表面能量分布;甲烷分子间作用能随吸附量的变化特点反映了超临界温度甲烷以类似于压缩气体状态聚集的特点和吸附剂结构上的差异。碳基吸附剂的比表面积和微孔容积是影响其储存甲烷容量的重要因素。     

Coating carbon nanotubes with polymer in supercritical carbon dioxide

A facile and efficient method has been developed for coating MWNTs with solvent resistant polymer in scCO2, which permits the selective deposition of high molecular weight fluorinated graft poly(methyl vinyl ether-alt-maleic anhydride) polymer onto MWNTs in scCO2 under 100-170 bar at 40 degrees C and forms quasi one-dimensional nanostructures with conducting cores and insulating surfaces.     

Glassy carbon electrodes modified with DNA-partly-wrapped single-walled carbon nanotubes

DNA-partly-wrapped single-walled carbon nanotubes (DNA-p-SWCNTs) were separated from the mixtures of calf thymus DNA and SWCNTs in solution by differential centrifugation for the first time. Average mass ratios of DNA to SWCNTs for DNA-p-SWCNTs and DNA-fully-wrapped-SWCNTs (DNA-f-SWCNTs) were determined to be 0.8 and 2.0, respectively. It has been found that DNA-p-SWCNTs could form a uniform and porous film on glassy carbon electrodes due to special structure of them, which could facilitate the electron transfer between positively-charged compounds and electrodes, and showed good enrichment capability at low ionic strength.     

Lattice dynamics of carbon chain inside a carbon nanotube

Based on the density functional theory, we obtain the optimum geometry of carbon chain inside a carbon nanotube. The phonon spectrum and specific heat of such a chain and nanotube hybrid system are calculated in terms of lattice dynamics theory. Some new phonon branches that have been obtained come from the coupling vibrations of the nanotube and the chain. The bending and stretching modes of the chain appear at about 520 cm(-1)and 1935 cm(-1) at Gamma point, respectively. It is found that the softening of G modes results mainly from the chain induced variations in the bond length on nanotube, independent of van der Waals interaction, while the stiffening of radial breathing mode is developed by the competition between the two factors. In the low-frequency region, the vibrational density of states are very different from that of the bare nanotube. Its specific heat implies the underlying quantized phonon structures and much large thermal conductivity in the hybrid system. In addition, the chain-length dependent vibration modes are calculated, from which it is expected that a finite chain of about 14 carbon atoms in the nanotube may produce the experimental Raman peak at about 1850 cm(-1).