微胶囊法对微量Pd（Ⅱ）萃取与洗脱的研究

微胶囊法对微量Ｐｄ（Ⅱ）萃取与洗脱的研究白光月，王玉洁，李永涛，张河哲（东北师范大学化学系，长春，１３００２４）毛北星（吉林省粮油专科学校，长春，１３００６２）关键词：微胶囊，钯的富集，三辛胺利用微胶囊膜对芯材的包埋性能，将油相萃取剂微胶囊化，使萃取...     

泡沫塑料对贵金属-碘化亚锡-络合物的吸附分离行为研究

本文通过泡沫塑料对贵金属-碘化亚锡络合体系富集分离的条件、性能和机理的研究,建立了一种泡沫塑料同时富集分离微量铂、钯、锗、铱、金的新体系.实验结果表明,在1.0mol/L HCl、0.6mol/L KI和0.01mol/L SnCl_2的溶液中,振荡吸附30min.各元素分配系数均在10~5以上,吸附容量(mmol/g)分别为:铂0.25、钯0.24、铑0.12、铱0.10、金0.52,回收率分别为:铂99.2％、钯98.6％、铑97.8％、铱98.0％、金97.8％.试样中贵金属采用ICP-AES、FAAS测定,该方法用于砂铂矿、废催化剂、铜阳极泥等物料中铂、钯、铑、铱、金的测定,测定结果与其它方法对照相符。本文还进行了吸附动力学研究和富集物的红外光谱分析。     

浊点萃取技术在金属离子分离和富集以及形态分析中应用的进展

介绍了新兴的环保型液液萃取方法——浊点萃取的原理及操作方法，讨论了影响浊点萃取效率的因素，重点回顾了近年来该技术在金属离子分离和富集以及形态分析中应用的进展，探讨了该技术的发展前景。     

铜印迹螯合树脂对金属离子的吸附特性

研究了铜印迹螯合树脂与非印迹螯合树脂对金属离子的吸附性能，结果表明：铜印迹树脂对Cu^2 、Ni^2 、Zn^2 的吸附量比非印迹树脂有显著增大,两者对Cu^2 的吸附速率均较快，其表观吸附速率分别为0．044s^-1和0．040s^-1；印迹树脂对Cu^2 的吸附可用Langmuir或Freundlish等温式来描述；其动态吸附曲线与离子的起始浓度相关；用0．5mol／L HCl即可快速洗脱吸附的Cu^2 ，树脂具有较强的再生能力，可以重复使用。     

Boronic acid functionalized Fe3O4 magnetic microspheres for the specific enrichment of glycoproteins

Glycoproteins are useful biomarkers and therapeutic targets for a number of diseases, including infections and cancer. However, identification and isolation of low‐abundant glycoproteins remains a significant challenge that limits their application. Thus, methods of specific and selective glycoprotein enrichment are required. In this study, novel phenylboronic acid functionalized magnetic microspheres were successfully synthesized. Fe₃O₄ microspheres were synthesized by using a hydrothermal method and were coated with tetraethyl orthosilicate using an ultrasonic method to form a core‐shell structure. Compared to the conventional mechanical stirring for 12 h, the ultrasonic method saved about 7 h in processing time, and the home‐made magnetic microspheres had better dispersibility and homogeneity. Subsequently, the magnetic microspheres were modified by addition of an amino group and a carboxyl group, in sequence. Finally, 3‐aminophenylboronic acid, as the functional monomer, was linked to the magnetic microspheres for capturing glycoprotein/glycopeptides. The results of this study indicate that phenylboronic acid functionalized magnetic microspheres show excellent adsorption performance toward glycoprotein/glycopeptides. The maximum absorbing capacity of the microspheres for fetuin was 108 mg/g, and the enrichment efficiency reached 89.7%, indicating their potential to separate and enrich glycoproteins from the complex biological samples.     

Evaluating docking programs: keeping the playing field level

Over recent years many enrichment studies have been published which purport to rigorously compare the performance of two or more docking protocols. It has become clear however that such studies often have flaws within their methodologies, which cast doubt on the rigour of the conclusions. Setting up such comparisons is fraught with difficulties and no best mode of practice is available to guide the experimenter. Careful choice of structural models and ligands appropriate to those models is important. The protein structure should be representative for the target. In addition the set of active ligands selected should be appropriate to the structure in cases where different forms of the protein bind different classes of ligand. Binding site definition is also an area in which errors arise. Particular care is needed in deciding which crystallographic waters to retain and again this may be predicated by knowledge of the likely binding modes of the ligands making up the active ligand list. Geometric integrity of the ligand structures used is clearly important yet it is apparent that published sets of actives + decoys may contain sometimes high proportions of incorrect structures. Choice of protocol for docking and analysis needs careful consideration as many programs can be tweaked for optimum performance. Should studies be run using ‘black box’ protocols supplied by the software provider? Lastly, the correct method of analysis of enrichment studies is a much discussed topic at the moment. However currently promoted approaches do not consider a crucial aspect of a successful virtual screen, namely that a good structural diversity of hits be returned. Overall there is much to consider in the experimental design of enrichment studies. Hopefully this study will be of benefit in helping others plan such experiments.     

Optimization of CAMD techniques 3. Virtual screening enrichment studies: a help or hindrance in tool selection?

Over the last few years many articles have been published in an attempt to provide performance benchmarks for virtual screening tools. While this research has imparted useful insights, the myriad variables controlling said studies place significant limits on results interpretability. Here we investigate the effects of these variables, including analysis of calculation setup variation, the effect of target choice, active/decoy set selection (with particular emphasis on the effect of analogue bias) and enrichment data interpretation. In addition the optimization of the publicly available DUD benchmark sets through analogue bias removal is discussed, as is their augmentation through the addition of large diverse data sets collated using WOMBAT.     

Improving database enrichment through ensemble docking

While it may seem intuitive that using an ensemble of multiple conformations of a receptor in structure-based virtual screening experiments would necessarily yield improved enrichment of actives relative to using just a single receptor, it turns out that at least in the p38 MAP kinase model system studied here, a very large majority of all possible ensembles do not yield improved enrichment of actives. However, there are combinations of receptor structures that do lead to improved enrichment results. We present here a method to select the ensembles that produce the best enrichments that does not rely on knowledge of active compounds or sophisticated analyses of the 3D receptor structures. In the system studied here, the small fraction of ensembles of up to 3 receptors that do yield good enrichments of actives were identified by selecting ensembles that have the best mean GlideScore for the top 1% of the docked ligands in a database screen of actives and drug-like "decoy" ligands. Ensembles of two receptors identified using this mean GlideScore metric generally outperform single receptors, while ensembles of three receptors identified using this metric consistently give optimal enrichment factors in which, for example, 40% of the known actives outrank all the other ligands in the database.     

Recent advances of rhenium separation and enrichment in China: Industrial processes and laboratory trials

The recent progresses in the separation and enrichment of rhenium were reviewed in this paper, especially, the advances in China.     

Sample enrichment in high speed narrow bore capillary gas chromatography

Reduction of the column diameter has proved to be a highly efficient tool to increase the speed of analysis. Unfortunately, the requirements for instrumental design with respect to sample input band width, low dead volume interfacing, and time constants of detection and registration systems are the more critical the smaller the inside diameter. Recently we reported input band widths as low as 1 ms [1] for gaseous samples at ppm concentration levels, without any preconcentration, in a study with narrow bore columns and thermal conductivity detection. In this study a simple versatile micro on-column cold trap/thermodesorption enrichment system for narrow bore columns is introduced and evaluated. The combination of considerable sample enrichment and preservation of the compatibility of the required input band width with column dimensions is critically examined. The process of thermodesorption (reinjection) which is the most critical step, is particularly emphasized. The system consists of a short aluminum coated fused silica or metal capillary with a low mass and a low cost electrical heating. Input band widths down to 1 ms are obtained without extreme demands on electrical power (300 watt). The potential of the system is illustrated with some extremely fast separations.