系列羟基苯基卟啉化合物荧光性质的研究

对照紫外光谱的变化分析了5种卟啉周边羟基的数目、位置及其在不同溶剂条件下的荧光光谱的变化情况.研究表明,利用控制卟啉周边取代基的数目、对称性及选择溶剂可获得不同强度的荧光物质.     

NaNO2/FeSO4存在下聚苯乙烯大分子引发剂的合成及嵌段共聚

用NaNO2/FeSO4·7H2O体系替代TEMPO在有机相中合成分子量可控的聚苯乙烯大分子引发剂,引发苯乙烯聚合及酯类单体[如甲基丙烯酸甲酯(MMA)、丙烯酸甲酯(MA)和丙烯酸乙酯(EA)等]聚合,得到两嵌段共聚物.其多分散性指数小于1.5,体现了可控聚合的特征.用大分子引发剂引发苯乙烯进行活性链增长,单体的转化率较高.嵌段共聚物的实测分子量与理论分子量相近,结构经1HNMR和GPC表征.NaNO2/FeSO4·7H2O体系在纯有机相中的应用降低了活性聚合的成本,有利于工业化应用.     

微波萃取高效液相色谱法测定口红中芳香胺类化合物

利用微波萃取高效液相色谱法测定了口红中芳香胺类化合物.先将口红涂于玻璃片上,然后用微波萃取和高效液相色谱法测定萃取液中的芳香胺类化合物.研究了3种市售口红并得到了芳香胺类化合物的定量测定结果.考察了微波萃取的条件,并将薄层色谱等萃取分离方法和微波萃取法进行了比较,证明微波萃取法在萃取膏状物和蜡状物中的组分时,具有比其它方法更加方便、快速等优点.     

高效液相色谱-荧光检测法测定罂粟籽和火锅汤料中的罂粟碱

用所建立的高效液相色谱-荧光检测法测定了罂粟籽和火锅汤料中的罂粟碱。采用的色谱柱为RP-C18柱(250 mm×4.6 mm i.d.,5 μm);检测激发波长为285 nm,发射波长为355 nm;流动相为甲醇-0.02 mol/L乙酸铵(体积比为70∶30),流速0.8 mL/min。实验结果表明,罂粟碱的进样量为1×10-4~0.1 μg时其质量浓度与相应峰面积有良好的线性关系,最低检测限(以信噪比大于3计)达到0.02 ng。罂粟籽中罂粟碱的回收率为99.0%～100.8%。方法快速准确,简便灵敏,分离度高,能够满足有关食品中罂粟碱的检测要求。     

头孢地嗪钠与牛血清白蛋白相互作用研究

用荧光光谱法研究水溶液中头孢地嗪钠(CDZM)与牛血清白蛋白(BSA)的结合反应, 测定了头孢地嗪钠与牛血清白蛋白的结合常数和结合位点数, 探讨了其荧光猝灭机制. 根据热力学参数确定了头孢地嗪钠与牛血清白蛋白之间的作用力类型, 运用Föster偶极-偶极非辐射能量转移原理, 测定了头孢地嗪钠与牛血清白蛋白相互结合时其授体-受体间的距离, 采用同步荧光技术考察了头孢地嗪钠对牛血清白蛋白构象的影响.     

Effects of diclofenac on EPC liposome membrane properties

In this work the interaction of a non-steroidal anti-inflammatory drug (NSAID), diclofenac, with egg yolk phosphatidylcoline (EPC) liposomes, used as cell-membrane models, was quantified by determination of the partition coefficient. The liposome/aqueous phase partition coefficient was determined by derivative spectrophotometry, fluorescence quenching, and measurement of zeta-potential. Theoretical models based on simple partition of the diclofenac between two different media, were used to fit the experimental data, enabling the determination of K_p. The three techniques used yielded similar results. The effects of the interaction on the membranes characteristics were further evaluated, either by studying membrane potential changes or by effects on membrane fluidity. The liposome membrane potential and the size and size-homogeneity of liposomes were measured by light scattering. The effects of diclofenac on the internal viscosity or fluidity of the membrane were determined by use of spectroscopic probes—a series of n-(9-anthroyloxy) fatty acids in which the carboxyl terminal group is located at the interfacial region of the membrane and the fluorescent anthracene group is attached at different positions along the fatty acid chain. The location of the diclofenac on the membrane was also evaluated, by fluorescence quenching using the same series of fluorescent probes. Because the fluorescent anthracene group is attached at different positions along the fatty acid chain, it is possible to label at a graded series of depths in the bilayer. The interactions between the drug and the probe are a means of predicting the location of the drug on the membrane.     

牛血清白蛋白与十二烷基硫酸钠作用的机理

利用电动势法得到了牛血清白蛋白(BSA)与十二烷基硫酸钠(SDS)相互作用的结合等温线. 通过四阶导数紫外光谱法和荧光光谱法研究了相互作用过程中芳香族氨基酸残基微环境极性的变化. 通过研究发现, 随着SDS浓度的逐渐增大, SDS在BSA上的平均结合数(v)逐渐增大, 色氨酸(Trp)残基所处微环境的极性在减弱后保持基本不变, 酪氨酸残基所处微环境的极性在明显增强后稍有减弱, 苯丙氨酸残基所处微环境的极性略有增强. 结果表明, 当v由0增大到14时, SDS主要结合在BSA的Trp-213附近并逐渐形成聚集体, 从而诱导BSA由结构域ⅡA 开始逐渐展开. 此后, SDS呈正协同作用的特点与BSA 结合, v急剧增大. 当v约为302 时, SDS在BSA上的结合基本达到饱和, BSA的构象趋于稳定.     

Determination of organophosphate and carbamate pesticides based on enzyme inhibition using a pH-sensitive fluorescence probe

A flow injection system for the determination of organophosphate and carbamate pesticides is described. A sensitive fluorescence probe was synthesized and used as the pH indicator to detect the inhibition of the enzyme acetylcholinesterase (AChE). The percentage inhibition of enzyme activity is correlated to the pesticide concentration. Several parameters influencing the performance of the system are discussed. The detection limits of 3.5, 50, 12 and 25 μg/l for carbofuran, carbaryl, paraoxon and dichlorvos, in pure water, respectively were achieved with an incubation time of 10 min. A complete cycle of analysis, including incubation time, took 14 min. The detection system has been applied to the determination of carbofuran in spiked vegetable juices (Chinese cabbage and cole), achieving recovery values between 93.2 and 107% for Chinese cabbage juice and 108 and 118% for cole juice at the different concentration levels assayed.     

CdS纳米粒子的表面修饰及其对光学性质的影响

用反胶束法合成了用表面活性剂分子磺基焉珀酸双－２－乙基已酯钠盐（ＡＯＴ）进行表面修饰的ＣｄＳ纳米粒子（记为ＣｄＳ／ＡＯＴ－ＳＯ３＾－）,研究了这种纳米粒子在正庚烷（ｈｅｐｔａｅ）和吡啶（Ｐｙ）溶剂中的荧肖及光解行为,发现其在正庚烷中荧光很强,而Ｐｙ却强烈地猝灭ＣｄＳ纳一子的荧光,用电荷转移猝灭机制进行了解释,这种解释为ＣｄＳ纳米粒子在Ｐｙ中光解实验进一步证实。     

液相色谱紫外法测定鸡肉中三种硝基咪唑残留量

建立了测定鸡肉中二甲硝咪唑、罗硝唑、甲硝唑残留量的方法。以二氯甲烷提取,硅胶固相萃取净化,液相色谱紫外法检测。样品添加１０μｇ／ｋｇ,５０μｇ／ｋｇ,平均回收率为７８％～９１％,相对标准偏差为６．４％～１０．１％。