有机溶剂中微量水分的测定

绕丹宁与水在有机溶剂中发生诱导荷移反应,产生吸收光谱移动且吸收峰增大。基于此,优化了实验条件,建立了一种快速、简便、灵敏的测定有机溶剂中微量水分的新方法。甲醇、醋酸溶剂中的水分含量分别在3％-10％（φ）、0～4％（φ）范围及乙醇、1-丙醇、丙酮、乙酸乙酯溶剂中水分含量在0～5％（φ）范围内与吸光度（A）呈线性关系。其相关系数分别是0．9992、0．9996、0．9992、0．9982、0．9990和0．9995。使用本方法测定了灯用酒精中水分含量,结果令人满意。     

共轭尺寸和表面氧化协同触发的红色荧光碳点用于有机溶剂中痕量水的检测

以邻苯二胺和盐酸多巴胺为前体,利用磷酸调节反应体系的pH值(pH=7, 3, 1),制备了荧光逐渐红移的碳点(CDs):CDs-7(绿光)、 CDs-3(橙光)和CDs-1(红光).通过透射电子显微镜(TEM)、拉曼光谱(Raman)、傅里叶变换红外光谱(FTIR)、 X射线电子能谱(XPS)、紫外-可见吸收光谱和荧光衰减曲线分析表明,反应体系pH值的减小促进了前体碳化交联,导致sp2共轭域尺寸和石墨化程度增加,从而使CDs的荧光红移.另外,酸性环境有利于使CDs表面氧化形成羧基,促进CDs荧光红移的同时改善了量子效率(QY).利用CDs-1量子产率高(14.8%)和发光的溶剂依赖特性,将其作为荧光探针分别检测了乙醇(EtOH)、 N,N-二甲基甲酰胺(DMF)和1,4-二氧六环(DIO)中的痕量水,检出限分别为0.86%, 0.123%和0.023%,表明CDs-1在痕量水的检测方面具有应用潜力.     

Preconcentration of Trace Elements in Water for Speciation Studies

Trace element speciation has recently become one of the most important problems in water analysis. Proper combination of preconcentration techniques with instrumental determination methods is essential to speciation analysis, because sensitivity and selectivity of direct determination methods are generally lacking. The present paper describes such preconcentration techniques as filtration, centrifugation, flotation and sorption, which have been developed in the author's laboratory for the speciation of heavy metals in river and pond waters by electron microscopy, X-ray microanalysis and chemical analysis. The application of freeze concentration to the speciation of silica in high-purity waters is also discussed.     

导数示波极谱法测定废水中微量对硝基乙苯

研究了导数示波极谱法测定废水中微量对硝基乙苯。在０．０１５ｍｏｌ·Ｌ－１乙二胺０．０１０ｍｏｌ·Ｌ－１ＥＤＴＡ底液中，对硝基乙苯产生一灵敏的二阶导数极谱峰，峰电位为－０．５４Ｖ（ｖｓＳＥＣ）。对硝基乙苯浓度在１．００×１０－７～７．００×１０－５ｍｏｌ·Ｌ－１范围内，浓度与峰电流成线性关系。检测限为１．００×１０－７ｍｏｌ·Ｌ－１。该法用于氯霉素药厂废水中对硝基乙苯的测定，取得满意的结果。     

Bismuth/Polyaniline/Glassy Carbon Electrodes Prepared with Different Protocols for Stripping Voltammetric Determination of Trace Cd and Pb in Solutions Having Surfactants

To improve reproducibility, stability and sensitivity, a bismuth (Bi) thin film was coated on glassy carbon (GC) substrates which surfaces were modified with a porous thin layer of polyaniline (PANI) via multipulse potentiostatic electropolymerization to form Bi/PANI/GC electrodes (Bi/PANI/GCEs). The Bi/PANI/GCEs were used successfully for simultaneous detection and determination of Cd²⁺ and Pb²⁺ ions, and various parameters were studied with reference to square wave anodic stripping voltammetric (SWASV) signals. The experimental results depicted that the environment‐friendly Bi/PANI/GCEs had the ability to rapidly monitor trace heavy metals even in the presence of surface‐active compounds.     

靛蓝-F-组合探针光度法检测非质子有机溶剂中的微量水

以靛蓝-F^-为组合探针,建立了非质子有机溶剂(DMSO、THF、DMF、二恶烷、乙腈)中微量水的比色检测新方法。结果表明,F^-加入靛蓝溶液后体系的颜色由蓝色变为黄绿色,进一步加入微量水之后,体系从黄绿色又变回蓝色,因而可作为一种变色探针实现对有机溶剂中微量水的裸眼识别检测。体系具有较高灵敏度,对DMSO、THF、DMF、二恶烷及乙腈中微量水的检测限分别为0.022%、0.043%、0.016%、0.34% 和0.015%。该方法实验操作简便、快速、灵敏、安全。实验结果表明,靛蓝与F^-的结合比为1:2。利用核磁滴定方法对机理进行了探讨。     

天然水中痕量铜的荧光测定

8-苯胺基-1-萘磺酸(ANS)可作为蛋白质研究的荧光探针^[1~3],ANS与可溶性的聚乙烯亚胺在微酸性溶液中以缔合物的形式结合,产生强烈的荧光并使ANS在水中的荧光激发和发射光谱分别产生红移和紫移,斯托克斯位移减小.当有痕量铜存在时,聚乙烯亚胺将与铜离子键合成聚合阳离子,它同ANS阴离子生成离子对后,由于ANS微环境极性的增强,导致荧光熄灭^[4],利用这一性质将水中痕量和超痕量的铜用巯基棉分离富集后进行测定,获得了满意结果,铜的检测下限为4.7ppb,对5至100ppb含量范围内铜的测定,相对标准偏不大于2.0%。     

A Comparison of Methods for the Determination of Available Trace Metals in Sea Water

Abstract

Two methods for the determination of available trace metals CCd, Pb, and Cu) in sea water are compared. One method employs anodic stripping voltammetry at controlled pH (8.1, 5.3, and 2); the other method involves sample pretreatment with Chelex-100 resin before ASV analysis. Differences in the results are discussed in terms of the definition of available metal and differences in the analytical methods.     

微量元素与防癌保健饮水器

简述了微量元素与人体健康的关系。人体主要是吸收周围环境溶解在水中的微量元素．各地区的环境差异造成微量元素的不平衡.为此介绍了以长寿地区饮用水为标准的改水器具——防癌保健饮水器．     

一种在非水介质中检测有机化合物微量水的电化学传感器

制备了聚二-(1,10-邻菲啰啉)(1,10-邻菲啰啉-5,6-二酮)合钌修饰玻碳电极,研究了在非水介质中与水反应后的电极反应,成功构建了一种检测微量水的电化学传感器,建立了在非水介质中检测有机物中微量水的电化学分析法.在含有0.05 mol/L六氟磷酸四丁基胺的乙腈溶液中,采用差分脉冲伏安法,在电位-0.12 V处测得的阳极峰电流与水含量在0.02％～5.66％范围内成正比,检出限为0.005％(S/N=3).将传感器分别应用于乙腈、丙酮、93号汽油、柴油4种有机物中微量水的测定,相对标准偏差小于3.6％,加标回收率为94.1％ ～ 105.0％,测定结果与卡尔费休法相符.     

Dynamics of Water Near Oxidized Polystyrene Films

Atomistic MD simulations of water in the vicinity of oxidized amorphous atactic polystyrene are presented. The changes in the orientational and translational dynamics of water near polymer surfaces with different hydrophilicity are studied. Two main orientational relaxation processes of water molecules are distinguished: a process on a fs timescale, associated with the ballistic motion of water molecules, and a process on a ps timescale, associated with the self‐diffusion of water. The fast process is not affected by the presence of the polymeric surface. The second relaxation process differs at the interface from that in the bulk in that the dynamics of water molecules is more heterogeneous in the first. The effect of the representation of polystyrene films on the water dynamics is discussed.

     

活性炭富集示波极谱法测定水中痕量钒

本文研究了钒在活性炭上的吸附行为和解吸附条件，建立了ｐＨ３－４条件下吸附，氢氧化钠溶液洗脱，示波极谱法测定水中痕量钒的方法，本法富集倍数为１００，对水样的最小检出浓度为０．０５μｇ／Ｌ加标回收率为８７．４％－１００．３％，７份平行样品测定的相对标准偏差为３。５％－１２．８％。     

Application of a Cation-Exchange Membrane to Determine Cations of Trace Metals in River Water

Donnan-membrane-equilibrium graphite-furnace atomic-absorption spectrophotometry (DME-GFAAS) has been developed to determine cations of trace metals in river water. The method employs a cation-exchange membrane to separate metal cations from their complexes; both total and cationic forms of metals were determined by means of GFAAS. The sensitivity of the method for the measurement of trace metal cations is determined by the detection limits of GFAAS for the metals of interest. Comparable concentrations of metal cations in water from NBS and from the Erhjen river were obtained between the DME-GFAAS and calculated (WATEQ4F) methods, indicating that the developed method is promising for natural fresh waters. The effect of pH on the distribution of metal cation in the NBS river water is significant for Cu and Pb; concentrations of these cations increase with decreasing pH. However, the concentrations of Cd and Zn cations do not vary with pH except that the concentration of the Zn cation decreases significantly as the pH value increases beyond 9. The method was applied to measure the capacity of complexing Cu in Chung-Lu river water, which was estimated to be 2.3 μM.     

糖尿病模型大鼠血清微量元素的测定

使用链脲佐菌素诱导出大鼠糖尿病模型,另设正常对照组,测定两组大鼠的血清镁,锌,铜,铬的含量,结果表明,糖尿病组较对照组血清锌,镁,铬低,而铜高（Ｐ〈０．０５）,血清锌与血糖,胰岛素,ＨｂＡｌｃ显著相关（Ｐ〈０．０５）,铜,铬与血清,胰岛素显著相关（Ｐ〈０．０５）。     

高分子混合物薄膜的相分离行为

从高分子混合物薄膜的相分离行为的机理，相分离后期粗化动力微区尺寸与时间的标度关系，影响高分子混合物薄膜表面形态形成的因素等几个方面对近年来高分子混合物薄膜相行为的研究进展进行总结，概述了今后可能的发展趋势。     

Kink-Block and Gauche-Block Structures of Bimolecular Films

Layer silicates and some other layer compounds can take up organic compounds such as long-chain alkanols and alkylammonium ions with formation of ordered bimolecular films. This system enables new ideas to be developed concerning the structure of monomolecular and bimolecular films: the films form reversible kink-block and gauche-block structures. Conclusions can be derived about the structure of the lipid layers in membranes.     

How Water Interacts with Halogenated Anesthetics: The Rotational Spectrum of Isoflurane–Water

The rotational spectra of several isotopologues of the 1:1 complex between the inhaled anesthetic isoflurane and water have been recorded and analyzed by using Fourier transform microwave spectroscopy. The rotational spectrum showed a single rotamer, corresponding to the configuration in which the most stable conformer of isolated isoflurane is linked to the water molecule through an almost linear C?H???O weak hydrogen bond. All transitions display a hyperfine structure due to the ³⁵Cl (or ³⁷Cl) nuclear quadrupole effects.     

A Humidity-Induced Large Electronic Conductivity Change of 107 on a Metal-Organic Framework for Highly Sensitive Water Detection

The electronic conductivity (EC) of metal–organic frameworks (MOFs) is sensitive to strongly oxidizing guest molecules. Water is a relatively mild species, however, the effect of H₂O on the EC of MOFs is rarely reported. We explored the effect of H₂O on the EC in the MOFs (NH₂)₂-MIL-125 and its derivatives with experimental and theoretical investigations. Unexpectedly, a large EC increase of 10⁷ on H₂SO₄@(NH₂)₂-MIL-125 by H₂O was observed. Brønsted acid–base pairs formed with the −NH₂ groups, and H₂SO₄ played an important role in promoting the charge transfer from H₂O to the MOF. Based on H₂SO₄@(NH₂)₂-MIL-125, a high-performance chemiresistive humidity sensor was developed with the highest sensitivity, broadest detection range, and lowest limit of detection amongst all reported sensing materials to date. This work not only demonstrated that H₂O can remarkably influence the EC of MOFs, but it also revealed that post-modification of the structure of MOFs could enhance the influence of the guest molecule on their EC to design high-performance sensing materials.