苯甲酸稀溶液的萃取特性

磷酸三丁酯;正辛醇;苯甲酸稀溶液的萃取特性     

Quantitation of seven polyoxypregnane glycosides in Marsdenia tenacissima using reversed-phase high-performance liquid chromatography-evaporative light-scattering detection

A high-performance liquid chromatography coupled with an evaporative light scattering detector (HPLC-ELSD) has been developed for the simultaneous determination of seven polyoxypregnane glycosides, tenacissosides A, B, G, H, I and marsdenosides C, G, in the stem of Marsdenia tenacissima, a Chinese herbal medicine. With a C18 analytical column, the analytes were separated efficiently using methanol-water as the mobile phase in a gradient program. The method limits of detection ranged from ca. 0.3 microg for marsdenoside C to ca. 0.5 microg for marsdenoside G and the method limits of quantitation from 1.0 microg for marsdenoside C to 1.7 microg for marsdenoside G, respectively. The intra- and inter-day precisions of the method were evaluated and all were less than 4%. All the recoveries for the spiked analytes exceeded 90%. This method was successfully used to analyze 19 samples of the stem of M. tenacissima.     

Validation study on 660 pesticide residues in animal tissues by gel permeation chromatography cleanup/gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry

A new method using gel permeation chromatography (GPC) cleanup followed by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS-MS) has been established for quantitative determination of 437 pesticide residues in animal tissues such as beef, mutton, pork, chicken, and rabbit. Based on an appraisal of the characteristics of both GC-MS and LC-MS-MS, validation experiments were conducted for 660 pesticides. In the method, 10 g animal samples were mixed with 20 g sodium sulfate and extracted with 35 mL of cyclohexane+ethyl acetate (1+1) twice by blender homogenization, centrifugation, and filtration. Evaporation was conducted and an equivalent of 5 g sample was injected into a 400 mm x 25 mm S-X3 GPC column, with cyclohexane+ethyl acetate (1+1) as the mobile phase at a flow rate of 5 mL/min. The 22-40 min fraction was collected for subsequent analysis. For the 368 pesticides determined by GC-MS, the portions collected from GPC were concentrated to 0.5 mL and exchanged with 5 mL hexane twice. For the 69 pesticides by LC-MS-MS, the portions collected from GPC were dissolved with acetonitrile+water (60+40) after taking the extract to dryness with nitrogen gas. In the linear range of each pesticide, the correlation coefficient was r > or = 0.98, exceptions being dinobuton, linuron, and fenamiphos sulfoxide. At the low, medium and high three fortification levels of 0.2-4800 microg/kg, recoveries fell within 40-120%, among which 417 pesticides recoveries between 60% and 120%, accounting for 95%, 20 analytes between 40% and 60%, accounting for 5%. The relative standard deviation was below 28% for all 437 pesticides. The limits of detection for the method were 0.2-600 microg/kg, depending on each pesticide.     

动物尿液中盐酸克伦特罗的分子印迹固相萃取-气相色谱-质谱法研究

采用分子印迹聚合物(MIP)固相萃取小柱提取、净化并富集猪尿液中的盐酸克伦特罗分子,用N,O-双三甲基硅基三氟乙酰胺(BSTFA)衍生化,毛细管气相色谱-质谱联用(选择离子模式,选择离子为277、262、243和86)对衍生物分析。优化了MIP固相萃取柱的淋洗条件,考察了MIP固相萃取柱的净化效果和消除基体干扰能力,建立了对动物尿液中盐酸克伦特罗的定性、定量分析的方法。在优化条件下,本法检出限(LOD)为0.51μg/L,定量限(LOQ)为1.00μg/L;不同盐酸克伦特罗加入量的回收率为71.0%~89.3%;相对标准偏差为3.2%~9.7%。将该方法与农业行业标准方法比较,结果吻合较好。但该方法灵敏度和精密度高,操作更为简单、快捷。     

2-呋喃甲硫醇修饰环糊精形成互锁式螺旋柱状超分子的自组装行为

利用单-(6-氧-对甲基苯磺酰基)-β-环糊精和2-呋喃甲硫醇反应得到单修饰环糊精, 单[6-硫-6-(2-甲基呋喃)]-β-环糊精. 通过X-ray衍射分析及核磁光谱等方法研究了其在溶液和固态中形成线状超分子的分子自组装行为. 结果表明, 化合物在固态中通过呋喃基团从第二面羟基连续插入到另一个环糊精的空腔, 形成了互锁式螺旋柱状超分子, 而且在溶液中也显示了相似的自组装行为, 其键合常数K及聚合度n分别为450 mol^-1·L和1.9.     

双亲聚合物分子印迹自组装胶束电化学传感器研究

结合大分子自组装和分子印迹技术制备了分子印迹聚合物胶束, 并通过电沉积将其固载到电极表面得到分子印迹电化学传感器. 首先以甲基丙烯酸二甲氨基乙酯(DMA)、丙烯酸羟乙酯(HEA)、丙烯酸二异辛酯(EHA)和苯乙烯(St)合成了共聚物poly(DMA-co-HEA-co-EHA-co-St), 在其侧链接枝上双键得到可光交联的双亲共聚物. 以水为沉淀剂诱发该双亲共聚物在含有对乙酰氨基苯酚的溶液中自组装, 得到印迹有对乙酰氨基苯酚的聚合物胶束, 利用动态激光光散射(DLS)和透射电镜(TEM)表征其尺寸和形貌. 最后通过电沉积技术诱导印迹胶束在金电极表面组装, 经紫外光辐照交联后, 洗脱模板分子形成分子印迹膜, 制备了对乙酰氨基苯酚分子印迹传感器, 通过循环伏安法、差分脉冲溶出伏安法研究此印迹传感器的性能. 实验结果表明, 该传感器对对乙酰氨基苯酚具有良好的选择性和灵敏度, 浓度响应线性范围为1×10^{-6 到4×10-3 mol/L, 检测限为3.3×10-7 mol/L.}     

微波处理和溶胶凝胶法共同改性废胶粉及其与天然橡胶复合材料性能的研究

采用微波处理打断废胶粉(WRP)的三维网状结构用来提高WRP在有机溶剂中的溶胀性,然后采用溶胶凝胶法,将微波改性后的WRP浸入正硅酸乙酯中,通过水解反应和缩合反应,在WRP表面原位生成SiO2网络,从而制得改性废胶粉(MWRP).将制得MWRP与天然橡胶(NR)共混,制备了NR/MWRP复合材料,研究了NR/MWRP复合材料的性能.通过热重分析仪、差示扫描量热仪和力学分析表明微波处理最佳时间是20 s.由于微波处理提高了NR与WRP的相容性,原位生成的SiO2粒子起到了补强作用,所以所制备的NR/MWRP复合材料拥有较好的力学性能;随着Si69的加入,抑制了SiO2粒子聚集,提高了SiO2粒子的分散性,从而进一步提高复合材料的力学性能并降低复合材料的Payne效应;在进行频率扫描时,硫化胶的储存模量随频率的增大而增大;硫化胶的温度扫描结果表明,随着温度的升高,复合材料中SiO2粒子聚集程度加剧并且复合材料出现老化的现象.为了提高复合材料的耐老化性能,N,N-间苯撑双马来酰亚胺(BMI)作为一种防老剂加入复合材料中,BMI利用Diels-Aider反应补偿橡胶在老化过程中所损失的交联键并提高NR与WRP的界面相容性,从而提高复合材料的耐老化性能.     

Electrochemical DNA Biosensor Based on Partially Reduced Graphene Oxide Modified Carbon Ionic Liquid Electrode for the Detection of Transgenic Soybean A2704‐12 Gene Sequence

In this work a partially reduced graphene oxide (p‐RGO) modified carbon ionic liquid electrode (CILE) was prepared as the platform to fabricate an electrochemical DNA sensor, which was used for the sensitive detection of target ssDNA sequence related to transgenic soybean A2704‐12 sequence. The CILE was fabricated by using 1‐butylpyridinium hexafluorophosphate as the binder and then p‐RGO was deposited on the surface of CILE by controlling the electroreduction conditions. NH₂ modified ssDNA probe sequences were immobilized on the electrode surface via covalent bonds between the unreduced oxygen groups on the p‐RGO surface and the amine group at the 5′‐end of ssDNA, which was denoted as ssDNA/p‐RGO/CILE and further used to hybridize with the target ssDNA sequence. Methylene blue (MB) was used as electrochemical indicator to monitor the DNA hybridization. The reduction peak current of MB after hybridization was proportional to the concentration of target A2704‐12 ssDNA sequences in the range from 1.0×10^?12 to 1.0×10^?6 mol/L with a detection limit of 2.9×10^?13 mol/L (3σ). The electrochemical DNA biosensor was further used for the detection of PCR products of transgenic soybean with satisfactory results.     

高效液相色谱-离子阱飞行时间质谱对保健食品中激素类成分的快速筛查和确证

采用高效液相色谱-离子阱飞行时间串联质谱(HPLC-IT-TOF-MS)对保健食品中雌激素、雄激素、糖皮质激素和二羟基苯甲酸内酯类药物等21种激素成分进行快速筛查、定性识别和准确定量。样品经含1.0%乙酸的乙腈溶液超声提取,提取液经QuEChERS吸附剂净化,以C18色谱柱(150 mm×2.0 mm, 3.0 μm)分离,乙腈和0.1%乙酸水溶液为流动相梯度洗脱,正、负离子模式同时扫描。结果表明,21种化合物在5.0～250 μg/L范围内呈良好的线性相关性,相关系数均大于0.993。胶囊和口服液样品中各化合物的定量限(以信噪比≥10计)分别为2.0～5.0 μg/kg和1.0～2.5 μg/L。在低、中、高3个添加水平下,各化合物的平均回收率为60.2%～116.0%,相对标准偏差(RSD)为7.0%～18.3%。该方法利用精确质量数匹配和自建标准谱库检索,实现快速筛查,并使用多级特征碎片离子进行确证,具有简便、快速、高效、准确等优点,适用于保健食品中多种激素的快速筛查和测定。     

Study on the Relation between Several Metal Ions and the Growth Metabolism of a Symbiotic Fungus of Sesarma bidens

对一株双齿相手蟹肠道共生真菌Sporothrix sp.(ZJSEF -7),测定了12种金属离子对该菌生长代谢的影响.结果表明,Fe3+、K+、Mn2+、Mg2+、Ca2+和Sb3+可明显促进菌体的生长;Cu2+、Sn2+和pb2+对菌体生长没有明显的影响;Fe2+对菌体生长有强的抑制作用;Al3+和Zn2+完全抑制菌体生长.相手蟹共生菌对部分重金属显示了一定的抗性和强的化学防御功能,深入研究其作用机制,将有助于了解相手蟹共生菌的生物学本质及其生态学作用,对于保护红树林生态环境具有重要的意义.