金属离子为探针分光光度法测定半胱氨酸

在pH 10.0的氨水-氯化铵缓冲溶液中半胱氨酸与钴(Ⅱ)或镍(Ⅱ)能生成金属络合物,其吸收峰分别位于284,274nm处;当钴(Ⅱ)的浓度为2×10-4 mol·L-1时,与之反应的半胱氨酸浓度在2.5×10-5~2.0×10-4 mol·L-1范围内与相应的吸光度之间呈线性关系,而当加入镍(Ⅱ)的浓度为1×10-4 mol·L-1时,则与之反应的半胱氨酸浓度在1.0×10-5~2.0×10-4 mol·L-1范围内与其吸光度之间呈线性关系。据此,提出可分别用钴(Ⅱ)或镍(Ⅱ)作为探针,以分光光度法测定半胱氨酸的含量。该方法可用于尿液中半胱氨酸的测定,加标回收率在95.7%~101%之间,测定值的相对标准偏差(n=5)在0.9%~3.3%之间。     

蓝晓科技

正西安蓝晓科技有限公司是专业从事吸附分离功能高分子材料的高新技术企业。公司集研发、生产和销售为一体。在西安高新开发区拥有1000余平方米的商务中心。在西安经济技术开发区泾河工业园区建有现代化的特种树脂生产基地和研发中心,占地面积40000余平方米,是目前为止国内最大的特种树脂生产基地,以及国内设备最先进、专业技术人员配置最完善的特种树脂研发中心。蓝晓科技是目前中国产量最大、品种最齐全的特种树脂制造商。年产特种树脂超过10000立方米,     

中国化学会第17届反应性高分子学术讨论会征文启事

正经中国化学会批准,中国化学会第17届反应性高分子学术讨论会定于2014年7月18~21日在常州大学召开,欢迎您报名参加,并欢迎您就下列内容踊跃投稿:1.离子交换材料、吸附材料、高分子催化剂、高分子试剂2.生物医用高分子材料3.新型反应性高分子(如高分子膜、纤维等分离材料)4.反应性高分子的合成、应用及表征论文摘要要求具有创新性、指导性,凡已在国内外学术会议上报     

Influence of Gd doping on the absolute quantum efficiency and lifetime of EuxGd1-x（TTA）3phens

Absolute quantum yield （Ф） is one of the most important parameters to evaluate the potential of novel materials. Lanthanide complexes EuxGd1-x（TTA）3phens are synthesized with the ratio of Gd3＋ dopant concentration ranging from 10% to 90% to improve the absolute quantum yield. EuxGd1-x（TTA）3phens possess similar infrared and ultraviolet spectra, showing that they have similar molecular structures. The absolute emission quantum yields of EuxGd1-x（TTA）3phens are determined using a fluoromax-4 spectrofluorometer equipped with an integrating sphere. The fluorescence lifetimes of the EuxGd1-x（TTA）3phens are measured in the same experiment. It was found that both absolute quantum yields and fluorescence lifetimes of EuxGd1-x（TTA）3phens are of quasi-periodic variation with the change of the Gd3. dopant concentrations. The absolute quantum efficiency and fluorescence lifetime vary with respect to the Gd content in an opposite fashion, indicating that the rate of energy absorption by the EuxGd1-x（TTA）3phens and the conversion to light energy is critical for the absolute quantum efficiency. The radiative rate constant Kr and non-radiative rate constant Knr are calculated. The dependence of Kr and Knr on the Gd3＋ dopant concentrations is very similar to that of absolute quantum efficiency. The radiation rate constant Kr and absolute quantum efficiency have a linear relationship.     

Determination of silver ion based on the redshift of emission wavelength of quantum dots functionalized with rhodanine

A simple and selective method for the determination of silver ions was developed by utilizing the red- shift in emission wavelength of the core-shell CdSe/Cd5 quantum dots （QDs） functionalized with rhodanine upon the addition of Ag＋. A linear relationship was observed between the shift and the increase in concentration of Ag＋ in the range of 0.0125-12.5 μmol/L. The mechanism of the red-shift was investigated and suggested that the coordination between Ag＋ and rhodanine on the QDs surface caused an increase of particle size, which resulted in the red-shift of the QDs＇ emission wavelength. A detection limit of 2 nmol/L was achieved. The developed method showed superior selectivity and was successfully applied to the determination of silver in environmental samples.     

Low generational polyamidoamine dendrimers to enhance the solubility of folic acid:A‘‘dendritic effect’’investigation

Low generational(G0–G2,G for generation) polyamidoamine(PAMAM) dendrimers were investigated as enhancers to improve the aqueous solubility of folic acid at pH 11 and pH 5.In these two cases,the solubility of folic acid increases with both the dendrimer concentration and generation.However,the solubilization mechanism is different.The electrostatic interaction between the primary amines of dendrimers and the ionized carboxylic groups of folic acid dominates the dissolution process at pH 11 while the increase of the solubility of folic acid at pH 5 is attributed to the hydrophobic encapsulation inside the dendrimer molecules.In addition,for comparison ethylenediamine was used as a small molecule control to examine the ‘‘dendritic effect' in the dendrimer-related solubilization process.Interestingly,PAMAM dendrimers exhibit,at pH 5,a significant superiority over ethylenediamine in enhancing solubility,whereas this ‘‘dendritic effect' cannot be observed under the basic condition.     

玻璃粉在陶瓷化硅橡胶中的应用

陶瓷化高分子材料具有优异的阻燃和防火性能,在国外已经有公司制备了这种材料来代替传统的防火材料。以硅橡胶为基体,通过添加玻璃粉,制备了一种陶瓷化高分子材料,研究了玻璃粉用量对硅橡胶力学性能和电学性能的影响,通过SEM观察了瓷化物表面和断面的形貌。结果显示,瓷化物表面比较致密,气孔较少,有一些玻璃相形成;断面存在大量气孔,具有较好的瓷化性能,瓷化物致密而又坚硬,可以抵抗至少1000℃的高温。随着玻璃粉添加量的提高,硅橡胶的流动性变差,硫化速率加快,拉伸强度和断裂伸长率都有不同程度的下降,邵氏硬度A一直上升,体积电阻率和表面电阻率则都呈现出先增大后减小的趋势。     

高效完成外专业高分子化学教学任务的思考与对策

在充分分析外专业学生的知识结构以及高分子化学知识体系的基础上,提出了一种以高分子化学实验为平台,课上教学与现场实践教学相结合,共同完成外专业高分子化学教学任务的新方法。教学实践结果表明该方法不但有效解决了外专业高分子化学课时少与课程教学内容多的矛盾,而且通过现场实践教学使学生在动手实践中充分体会到了高分子化学的理论知识在日常生活中的重要作用,做到了学与用相结合、理论与实践相结合、课上学习与课下学习相结合。该教研成果为高效完成外专业高分子化学教学任务提供了新思路。     

流动注射光度法快速测定海水中的COD_(Mn)

采用流动注射光度法对海水化学需氧量(CODMn,高锰酸盐指数)进行快速测定。实验以KMnO4作氧化剂,淀粉-KI作显色剂,葡萄糖作标准物质;对流动注射分析流路进行了设计,优化了反应圈长度、反应温度、反应物浓度、进样量、泵速等实验条件;并通过自动加热装置对反应器进行在线加热;在最优条件下,测定方法的线性范围为0~6mg·L-1(实际需氧量),最低检出限为0.13mg·L-1,实际海水测定时加标回收率在96%~104%范围内,对1mg·L-1的COD标准溶液进行了11次连续测定,相对标准偏差(RSD)为1.88%。该方法操作简单、方便、灵敏度高,用于海水实际样品分析时,其测定值与国标法测定值一致。