Highly luminescent, stable, and water-soluble CdSe/CdS core-shell dendron nanocrystals with carboxylate anchoring groups

A dendron ligand with two carboxylate anchoring groups at its focal point and eight hydroxyl groups as its terminal groups was found to efficiently convert as-synthesized CdSe/CdS core-shell nanocrystals in toluene to water-soluble dendron-ligand stabilized nanocrystals (dendron nanocrystals). The resulting dendron nanocrystals retained 60% of the photoluminescence value of the original CdSe/CdS core-shell nanocrystals in toluene and were significantly brighter than the similar dendron nanocrystals with thiolate (deprotonated thiol group) as the anchoring group which retained just 10% of the photoluminescence value of the original CdSe/CdS core-shell nanocrystals in toluene. The carboxylate-based dendron nanocrystals survived UV irradiation in air for at least 13 days, about 9 times better than the thiolate-based dendron nanocrystals (35 h) and similar to that of the thiolate-based dendron-box stabilized CdSe/CdS core-shell nanocrystals (box nanocrystals). Upon UV irradiation, the dendron nanocrystals became even 2 times brighter than the original CdSe/CdS core-shell nanocrystals in toluene, and the UV-brightened PL can retain the brightness for at least several months. These stable and bright dendron nanocrystals were soluble in various aqueous media, including all common biological buffer solutions tested, for at least 1.5 years. In addition to their superior performance, the synthetic chemistry of carboxylate dendron ligands and the corresponding dendron nanocrystals is relatively simple and with high yield.     

超高效液相色谱-电喷雾串联质谱法测定动物饲料中的大环内酯类和林可胺类抗生素

建立了动物饲料中竹桃霉素、红霉素、吉他霉素、交沙霉素、罗红霉素、泰乐菌素6种大环内酯和林可霉素、克林霉素2种林可胺抗生素的超高效液相色谱-电喷雾串联质谱(UPLC-ESI-MS/MS)检测方法。饲料样品采用甲醇提取,Oasis HLB固相萃取柱富集净化,Waters Acquity UPLC BEH C18色谱柱分离,以0.1%甲酸和乙腈为流动相进行梯度洗脱,流速为0.3 mL/min,正离子模式扫描,多反应监测模式检测,外标法定量。实验结果表明,8种药物在1～100 μg/L范围内具有良好的线性关系。在空白饲料样品中分别添加1、10和100 μg/kg 3个加标水平的8种药物,其平均回收率为68.6%～95.2%,相对标准偏差(RSD)为4.9%～11.8%,定量限均为1 μg/kg。结果表明,该方法简便快速、灵敏度高,适用于动物饲料中大环内酯类和林可胺类抗生素的同时检测。     

仪器分析课程教学实践

在仪器分析课程的教学实践中,采取加强绪论课教学,引入仪器分析发展史,运用生活化的形象描述及比喻,以及充分利用多媒体教学手段4种方法,培养和激发学生学习兴趣。     

物理专业普通化学课程教学改革初探

结合物理专业特点,从确立课程主线入手进行普通化学教学内容和教学方式改革,使教师授课和学生学习的重点更为突出,内容更加新颖丰富。     

耐辐照玻璃成分分析标准物质的研制

采用高温熔融方法制备了玻璃成分分析标准物质.对标准物质的制备技术、均匀性检验、稳定性考察及定值不确定度进行了分析.研制的耐辐照成分分析标准物质具有良好的均匀性和稳定性,各组分不确定度均小于5％.     

细胞色素C的电化学行为研究

本文评述了细胞色素Ｃ电化学研究的发展概况，重点介绍了细胞色素Ｃ在促进剂作用下的电化学行为，促进剂种类，影响促进作用的因素及促进机理。     

Efficient and color-tunable Mn-doped ZnSe nanocrystal emitters: control of optical performance via greener synthetic chemistry

Formation of Mn-doped ZnSe quantum dots (Mn:ZnSe d-dots) using nucleation-doping strategy was studied systematically and optimized through greener approaches. The resulting d-dots were with high ( approximately 50%) photoluminescence (PL) quantum yield (QY), which was achieved by the controlled formation of small-sized MnSe nanoclusters as the core and a diffused interface between the nanocluster core and the ZnSe overcoating layers. Synthesis of the d-dots under high temperatures (240-300 degrees C) was achieved by varying the structure of the metal carboxylate precursors, concentration of the inhibitors, free fatty acid, and concentration of the activation reagents, fatty amines. Highly emissive d-dots synthesized under desired conditions were found to be extremely stable upon thermal treatment up to the boiling point of the solvent (about 300 degrees C), which was quantitatively studied using in situ measurements. The PL peak of the d-dots was controllably tuned in a surprisingly large optical window, from 565 to 610 nm. These highly emissive and stable d-dots possess characteristics of practical emissive materials, especially for applications requiring high power, high concentration of emitters, and under tough conditions.