Review of recent advances in the preparation of organic polymer monoliths for liquid chromatography of large molecules

In recent years the use of monolithic polymers in separation science has greatly increased due to the advantages these materials present over particle-based stationary phases, such as their relative ease of preparation and good permeability. For these reasons, these materials present high potential as stationary phases for the separation and purification of large molecules such as proteins, peptides, nucleic acids and cells. An example of this is the wide range of commercial available polymer-based monolithic columns now present in the market.     

Speciation of Charged Complexes by Donnan Dialysis

Abstract

The assignment of metal complexes to various regimes on the basis of their dissociation kinetics is one type of metal speciation study. The most common scheme, which involves column ion-exchange as a means of separating free metal ions and metals in the form of highly labile complexes from other forms of metals in the sample, is demonstrated to categorize incorrectly stable, charged complexes such as iron(II) and nickel(II) o-phenanthroline as labile. Donnan dialysis is an alternative ion-exchange method for metal speciation studies. Data are provided which demonstrate that the above complexes are correctly assigned by the Donnan dialysis method. The relative labilities of ethylenediamine and triethylenetetramine complexes of iron (II) and nickel (II) are also correctly determined by Donnan dialysis.     

Ion-Exchange Preconcentration and Separation of Trace mounts of Platinum and Palladium

ABSTRACT

The preconcentration and separation of platinum and palladium from weakly acidic solution (pH=4) were done on microcolumn packed with Cellex-T resin. Selective platinum elution from the column was performed with 0.01 mol/l glycine solution at pH=12, while for palladium elution 1.2 mol/l thiourea (pH=0.5) or 4.0 mol/l potassium thiocyanate (pH=1) may be used. As the detection technique was used either FAAS or GFAAS, depending on the concentration of studied metals in the eluate.     

单斜层状LiMn0.97Al0.03O2-x(PO4)x材料的合成及其电化学性能

以Na₂CO₃, (CH₃CO₂)₂Mn·4H₂O, Al₂O₃, Na₃PO₄·12H₂O和CH₃COOLi·2H₂O为原料, 通过2次高温固相法和一步水热离子交换法得到一系列铝和磷掺杂的LiMn_0.97Al_0.03O₂, LiMnO_1.99(PO₄)_0.01和LiMn_0.97Al_0.03O_2-x(PO₄)_x(x=0.01, 0.03, 0.05)化合物. 用X射线衍射(XRD)表征了前驱体及交换产物的晶体结构, 用扫描电镜(SEM) 测定了晶体的形貌. 通过X射线光电子能谱(XPS)、傅里叶红外光谱及恒电流充放电测试, 研究了掺杂离子对合成材料结构及电化学性能的影响. 研究结果表明, Al-PO₄复合掺杂综合了Al³⁺掺杂提高材料的电化学反应活性和减低材料的电化学反应阻抗以及PO₄^3-掺杂增大材料的晶胞体积的特点, 提高材料中Li⁺的扩散能力, 有效地抑制了材料由于Jahn-Teller效应引起的结构畸变, 改性后的LiMnO₂正极材料既保持了较高的容量又获得了良好的电化学循环性能.     

Chemfet Based Microsensors Covered with Ion-Partitioning Polymeric Membranes

 The development of a new type of microsensors based on chemically sensitive field-effect transistors (CHEMFETs) covered with polymeric bulk ion-partitioning membranes is presented. For the construction of the microsensor, a PVC plasticized membrane containing two ionophores, one selective to protons and the other to the analyte cation of interest, is placed on the gate of a pH sensitive field-effect transistor which acts as the transducer. With the use of thin (5–10 μm) ion-partitioning membranes onto the pH-sensitive ISFET gate, the proton displacement out of the membrane and to the pH sensitive gate is fast and reversible. This displacement generates a signal that is directly related to the analyte concentration found in the test solution. Comparing the performance of CHEMFETs and ISEs selective to the monovalent potassium cation and the divalent calcium ion validates this novel CHEMFET response mechanism.     

全氟磺酸树脂/SiO2催化合成邻苯二甲酸二辛酯

全氟磺酸树脂/SiO2催化合成邻苯二甲酸二辛酯;固体酸;全氟磺酸离子交换膜;全氟磺酸树脂/SiO2复合物催化剂;邻苯二甲酸二辛酯     

Miniaturized Salinity Gradient Energy Harvesting Devices

Harvesting salinity gradient energy, also known as “osmotic energy” or “blue energy”, generated from the free energy mixing of seawater and fresh river water provides a renewable and sustainable alternative for circumventing the recent upsurge in global energy consumption. The osmotic pressure resulting from mixing water streams with different salinities can be converted into electrical energy driven by a potential difference or ionic gradients. Reversed-electrodialysis (RED) has become more prominent among the conventional membrane-based separation methodologies due to its higher energy efficiency and lesser susceptibility to membrane fouling than pressure-retarded osmosis (PRO). However, the ion-exchange membranes used for RED systems often encounter limitations while adapting to a real-world system due to their limited pore sizes and internal resistance. The worldwide demand for clean energy production has reinvigorated the interest in salinity gradient energy conversion. In addition to the large energy conversion devices, the miniaturized devices used for powering a portable or wearable micro-device have attracted much attention. This review provides insights into developing miniaturized salinity gradient energy harvesting devices and recent advances in the membranes designed for optimized osmotic power extraction. Furthermore, we present various applications utilizing the salinity gradient energy conversion.     

离子交换色谱法分离青枯菌及其色谱峰的鉴定

采用离子交换色谱法对世界上分布最广、危害最重且最难防治的植物致病菌青枯菌进行了色谱表征。在以0.02 mol/L哌嗪-盐酸缓冲液(pH 8.0)为流动相、梯度洗脱条件下,青枯菌在SuperQ-650 C色谱柱(200 mm×4.6 mm i.d.)上被分离为3个不同的色谱峰。根据这3个组分的形态和生理生化性质,确定青枯菌原液和分离得到的3个组分都属于青枯菌的生化型Ⅲ型。通过2,3,4-三苯基氯化四氮唑(TTC)平板鉴定两个洗脱峰菌体的致病性及电镜观察二者的运动性,发现第一洗脱峰菌体的致病性弱于第二洗脱峰菌体而运动性强于后者。实验表明,通过离子交换色谱可以把常规微生物方法无法分离的青枯菌的不同状态区分出来。分离结果将为阐明青枯菌的多态性及传代培养过程中致病性逐渐减弱的内在机理,最终研制出特效的青枯菌抗菌剂具有重要意义。     

Synthesis of o-LiMnO2 by Microwave Irradiation and StudyIts Heat Treatment and Lithium Exchange

Microwave irradiation of a suspension of γ-MnOOH in a 4 mol dm⁻³ LiOH solution brought about a rapid formation of semicrystalline orthorhombic LiMnO₂ (o-LiMnO₂) within 30 min at 120°C. Cubic Li_1.6Mn_1.6O₄ was obtained by heating o-LiMnO₂ at 400°C; lithium could be topotactically extracted from Li_1.6Mn_1.6O₄ with acid to form cubic H_1.6Mn_1.6O₄.     

Separation and purification of scandium: From industry to medicine

Scandium and its compounds are used in many modern industrial fields due to its unique chemical and physical properties. It is mainly recovered from residues and wastes in the production of other metals. The exploitation of the ores and wastes could contaminate water and soil creating environmental problems. This paper discusses recent developments and tendencies in scandium separation, purification and preconcentration from different wastes, residues, environmental samples as well as in the production of radiopharmaceuticals for nuclear medicine, both in the laboratory and on the industrial scale. The period reviewed here mainly includes publications that have appeared, since 2010.