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Lei Zhang Chenyang Zhang Xin Dong Zeyuan Dong 《Angewandte Chemie (International ed. in English)》2023,62(6):e202214194
Lithium ions have been applied in the clinic in the treatment of psychiatric disorders. In this work, we report artificial supramolecular lithium channels composed of pore-containing small aromatic molecules. By adjusting the lumen size and coordination numbers, we found that one of the supramolecular channels developed shows unprecedented transmembrane transport of exogenous lithium ions with a Li+/Na+ selectivity ratio of 23.0, which is in the same level of that of natural Na+ channels. Furthermore, four coordination sites inside channels are found to be the basic requirement for ion transport function. Importantly, this artificial lithium channel displays very low transport of physiological Na+, K+, Mg2+, and Ca2+ ions. This highly selective Li+ channel may become an important tool for studying the physiological role of intracellular lithium ions, especially in the treatment of psychiatric disorders. 相似文献
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The ion-trapping ion cyclotron resonance spectrometer, or Fourier transform mass spectrometer, provides a powerful and convenient environment for the study of photodissociation of gas-phase ions. This capability has been explored for about 30 years in a number of laboratories including our own. A variety of developments and applications, historical and current, are organized here under five broad headings: (1) optical spectroscopy of ions; (2) kinetics of the dissociation process; (3) dynamics of the dissociation process; (4) thermochemistry of dissociation; and (5) probing the structure and energy of the ions. 相似文献
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Poly (styrene/divinyl benzene) with cryptand 22 as an anchoring group was synthesized and applied as a bifunctional packing material for the separation of both cations and anions. At pH < 2, the resin can be protonated and applied as an anion exchanger for the separation of anions; with water as eluent, inorganic anions such as F?, Cl?, Br?, NO3?”, I? were well separated. After deprotonation at pH> 10, the resin became a cation exchanger and successfully separated alkali metal ions such as Li+, K+ and Cs+ with methanol as eluent. The effects of solvents, flow rate and temperature on the separation of various ions were also investigated. 相似文献
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利用红外光谱研究了NaNO3和NaClO4在N,N-二甲基甲酰胺(DMF)溶剂中发生离子-溶剂和离子-离子的相互作用, 分析结果表明, DMF的OC-N谱带发生了明显的变化. 定量计算了在Na+浓度为0.22~1.24 mol/kg范围内的溶剂化数为1~4. 对谱图中酰胺基上C-N和CO的特征峰强度随Na+浓度变化的对比, 推测离子溶剂化作用导致DMF的酰胺基内部形成共轭键. 利用量子化学方法进行优化及热力学性质计算, 得到C-N键伸缩振动频率及红外光谱强度变化规律. 优化结构与实验结论相符合. 由NaNO3的ν2谱带及NaClO4的ν1谱带的解析得到溶液中阴离子缔合效应的一般规律, 并通过阴离子缔合特征峰与酰胺基上的N-C-N面外振动峰(865 cm-1)的变化情况, 讨论了溶液中的离子溶剂化作用. 相似文献
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柱后衍生离子色谱法同时测定水中Fe^3+,Fe^2+,Cu^2+,Zn^2+方法研究 总被引:5,自引:0,他引:5
将Dionex 4000i离子色谱仪和国产721分光光度计组合联用,建立了一种同时测定水中Fe~(3+)、Fe~(2+)、Cu~(2+)、Zn~(2+)四种金属离子的柱后衍生离子色谱法。以磺基水杨酸/酒石酸/草酸为络合剂,质子化的二价乙二胺离子(EnH_2~(2+))为淋洗离子,在Dionex HPIC-CS2分离柱上先实现混合金属离子的分离,之后,各被分离的离子依次进入柱后反应器,与PAR在此反应显色生成有色络合物。借助国产721分光光度计,在500 nm的固定波长下依次检测流出的各离子。Fe~(3+)、Fe~(2+)、Zn~(2+)三种离子仅需6 min就可全部淋洗出。Cu~(2+)在切换淋洗液后检测,也仅需10 min。本法可用于同时测定天然水(mg/L级浓度)和电站高纯水(μg/L级浓度)以及金属腐蚀产物中的Fe~(3+)、Fe~(2+)、Cu~(2+)、Zn~(2+)。进样分析前,仅需将水样酸化和过滤即可。 相似文献
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GUO Li-li WANG Dong-xia Roger W. Roeske 《高等学校化学研究》2006,22(2):265-266
Introduction PeptidesmadeupofalternatingL andD amino acidscanformβhelicesasingramicidinAorcyclic peptidesthataggregatetoformtubes[1].Inbothcases thestructuresarehollowwithallthesidechainspro jectingoutwards.Kennedyetal.[2]postulatedthat peptideshavingthe… 相似文献
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本文提出一种新型的离子色谱方法,采用恒电流电场代替机械泵输送离子,研制出体积小、重量轻、成本低、易操作的电迁移微离子色谱仪,并检测了几种常见的阴离子,Cl~-、Br~-、NO_2~-的检测极限为10~(-11)~10~(-12)mol,峰高和保留时间重现性相对标准偏差均<3%,进样量与峰高的线性关系良好。 相似文献
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范卫平 《中国无机分析化学》2021,11(2):15-20
建立了一种抑制电导检测器离子色谱法同时测定那屈肝素钙中氯离子和硫酸根离子含量的方法.采用强阴离子交换柱,3 mmol/L碳酸钠溶液为流动相,流速2.0 mL/min,柱温30℃,进样量25μL,检测器为配有化学抑制器的电导检测器.结果表明,氯离子和硫酸根离子在1~20μg/m L浓度范围内线性关系良好,氯离子线性方程为... 相似文献
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A solid state copper(II) ion sensor is reported based on the application of electropolymerized undoped (neutral) polycarbazole
(PCz) and polyindole (PIn) modified electrodes. The new sensor shows high selectivity to Cu2+ ions with a detection limit of 10–5 M. PCz and PIn are formed respectively by the anodic oxidation of 50 mM carbazole and 5 mM indole monomers in dichloromethane
containing 0.1 M tetrabutylammonium perchlorate on a platinum electrode using a single compartment cell. Potentiostatic polymerization
of both the monomers are carried out at 1.3 V and 1.0 V vs. Ag/AgCl, respectively. Perchlorate ions were electrochemically
removed from the polymer films by applying – 0.2 V vs. Ag/AgCl. Polymer-coated electrodes are incubated in 1 M KCl solution
for 8 h followed by incubation in distilled water for 2 h before using as a metal ion sensor. The undoped PCz and PIn electrodes
were found to be highly selective and sensitive for Cu2+ ions with little selectivity for Pb2+ and negligible response towards Ag+, Hg2+, Cu+, Ni2+, Co2+, Fe2+, Fe3+ or Zn2+. Potentiometric responses for Cu2+ ions are recorded for both the sensor electrodes together with a double-junction Ag/AgCl reference electrode. Calibration
curves for Cu2+ are reported for both ion sensors. The polymer-modified electrodes were found to be stable for several weeks.
Electronic Publication 相似文献
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Polymer evolution of a sulfonated polysulfone membrane as a function of ion beam irradiation fluence
Ion beam irradiation was used to modify the surface of a sulfonated polysulfone water treatment membrane. A beam of 25 keV H+ ions with three irradiation fluences (1 × 1013 ions/cm2, 5 × 1013 ions/cm2, and 1 × 1014 ions/cm2) was used for membrane irradiation. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) analyses were performed on the virgin and irradiated membranes in order to determine the changes to chemical structure incurred by ion beam irradiation. The results show that some of the sulphonic and CH bonds were broken and new CS bonds were formed after irradiation. Atomic force microscope (AFM) analyses show that membrane roughness decreased after irradiation. A significant increase in flux after ion beam irradiation was also observed, while the amount of cake accumulation on the membrane was decreased after ion beam irradiation. Hydrophobicity, pore size distribution and selectivity of the membrane were not affected by ion beam irradiation. 相似文献
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潮湿空气微波放电离子形成动力学 总被引:2,自引:0,他引:2
利用微波放电电离质谱装置,通过水蒸气与空气混合气体(潮湿空气)的微波放电,同时获得了化学电离质谱探测技术中常用的三种重要母体离子H3O+、NO+和.结合潮湿空气中主要成分N2、O2以及水蒸气各自微波放电后的质谱探测结果,对潮湿空气微波放电后上述三种离子产生的动力学过程进行了分析,并给出了各种离子的形成机制.这些离子 分子反应过程在计算机模拟中得到了进一步的证实. 相似文献
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离子交换树脂在分析化学中的应用 总被引:1,自引:0,他引:1
简要评述了离子交换树脂在分析化学中的应用。包括离子交换树脂预富集技术从稀溶液中浓缩痕量离子,离子交换树脂相分光光度法测定微量离子,离子色谱在无机分析中的应用,以及离子交换树脂在有机分析与生化分析中的应用。 相似文献
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等离子体基低能离子注入的光谱诊断 总被引:1,自引:0,他引:1
采用发射光谱(OES)技术系统地研究了电子回旋共振(ECR)微波等离子体基低能离子注入的等离子体特性。结果表明:纯氮气形成的等离子体中的活性粒子主要是N2和N+2,等离子体中电子与气体分子碰撞使N2产生激发和电离,而使N2离解的作用很小;氮氩混合气形成的等离子体中,随着氩气分压的增加,N2和N+2的浓度降低,同时氩气对氮分子离解的贡献很小;直接施加于试样的脉冲负偏压对等离子体特性没有明显影响,但存在着一定的溅射作用。 相似文献
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Beatriz Brasil Ricardo J.N. Bettencourt da Silva M. Filomena G.F.C. Camões Pedro A.S. Salgueiro 《Analytica chimica acta》2013
The linear weighted regression model (LW) can be used to calibrate analytical instrumentation in a range of quantities (e.g. concentration or mass) wider than possible by the linear unweighted regression model, LuW (i.e. the least squares regression model), since this model can be applied when signals are not equally precise through the calibration range. If precision of signals varies within the calibration range, the regression line should be defined taking into account that more precise signals are more reliable and should count more to define regression parameters. Nevertheless, the LW requires the determination of the variation of signals precision through the calibration range. Typically, this information is collected experimentally for each calibration, requiring a large number of replicate collection of signals of calibrators. This work proposes reducing the number of signals needed to perform LW calibrations by developing models of weighing factors robust to daily variations of instrument sensibility. These models were applied to the determination of the ionic composition of the water soluble fraction of explosives. The adequacy of the developed models was tested through the analysis of control standards, certified reference materials and the ion balance of anions and cations in aqueous extracts of explosives, considering the measurement uncertainty estimated by detailed metrological models. The high success rate of the comparisons between estimated and known quantity values of reference solutions, considering results uncertainty, proves the validity of developed metrological models. The relative expanded measurement uncertainty of single determinations ranged from 1.93% to 35.7% for calibrations performed along 4 months. 相似文献