pH值对钙离子选择电极响应电位的影响

测量溶液中Ca^2 浓度的方法有原子吸收分光光度法、离子色谱法、EDTA络合滴定法和钙离子选择电极法(ISE)。其中由于ISE法具有快速、灵敏、测量设备简单及试液用量很少,做到无损分析和原位测量、适于连续自动分析等特点,受到化学分析工作者的青睐。目前大多数文献和有关钙ISE的使用说明书中,认为在电极的pH值使用范围内,只要溶液中钙     

石墨烯基电极材料的设计和构建及其在电容去离子中的应用

电容去离子(CDI)是一种通过静电力作用将离子从水中去除的技术,电极是整个装置中为最为核心的部件,石墨烯因具有优异的导电性和巨大的比表面积等优势成为当前CDI电极材料的研究热点之一。目前对于CDI石墨烯电极的研究主要集中于石墨烯电极的合成,然而有关CDI性能与石墨烯电极制作工艺及电极材料自身结构之间的关系,缺少相关综述。本文系统介绍了CDI的基本原理与性能指标,综述了石墨烯电极材料的研究进展与电极制作工艺,重点分析、归纳和总结了石墨烯材料的特性(孔隙结构、导电性、亲疏水性)对CDI性能的影响,最后对CDI中石墨烯电极材料今后的发展进行了总结和展望。     

聚氯乙烯膜碘离子选择电极在溴碘离子共存体系分析中的应用

介绍了聚氯乙烯膜碘离子选择电极(PVC-I-ISE)的制备方法,电极对碘离子的能斯特响应斜率为59 mV/pI,响应的线性范围为4.0×10-5~1.0×10-2mol.L-1,检出限为1.6×10-5mol.L-1,低于用银ISE的检出限,电极的使用寿命为一个月以上。将制备的碘离子选择电极作为指示电极用于对溴、碘混合离子体系进行连续分别电位滴定,并与以银电极为指示电极的电位滴定方法进行了比较。结果表明用PVC-I--ISE作指示电极,可在I--Br-共存的混合溶液中进行两离子的连续电位滴定,而用银-ISE时则不能。     

流动注射测碘仪研制及测定西地碘含片中碘

基于流动注射分析(FIA)-离子选择电极(ISE)技术,研制了一种流动注射测碘仪,建立了流动注射药碘测定方法。在ISE电极架内设计了反流管,使溶液离开ISE膜表面反流至参比电极的安置腔内后,能够迅速从四个微型沟道流出,提高了测碘仪的响应速度。参比电极与ISE电极间有上下双沟道设计,保证参比电极的盐桥端没有气泡经过,参比电位稳定。测量碘的线性范围为0.0497～4 mg/L,线性相关系数为0.9988,检出限为0.0497 mg/L。方法可用于西地碘含片中碘含量的测定。     

土壤中十四种元素的ICP-AES和ISE的碱熔直接测定

报道了应用直读型电感耦合等离子体发射光谱(ICP-AES)及离子选择电极(Ion-SelectiveElectrode,简称ISE)成功地测定土壤中十四种难测元素的方法及其精度。土壤样品经过NaOH高温熔融、用水定容后,直接在强碱性溶液中用ICP-AES测定通常较难测定的十三种元素;Se、Mo、B、As、Si、S、Pb、P、Ge、Sn、Sb、Cr、K。通过ISE亦能很好地测定F。     

具有阴阳离子插入行为的电容去离子电极设计

具有离子嵌入/脱嵌能力的离子插层型电容去离子(CDI)电极材料是一类具有很高比容量的新型CDI电极,可以有效改善传统碳材料电极离子存储容量有限、电极易腐蚀的缺点.本文以金属氧化物、过渡金属/碳/氮/碳氮化物(MXenes)、钠超离子导体(NASICON)型磷酸盐材料等为分类,综述了近几年具有代表性的基于离子嵌入/脱嵌的...     

聚合物在离子选择电极上的应用

本文概述了聚合物膜离子选择电极的发展、制备、应用等方面的研究情况。分别对固态膜类和液膜类聚合物膜离子选择电极的优缺点和发展前景进行了分析,并讨论了聚合物在膜电极中的作用,以及聚合物的结构对膜电极性能的影响。     

电化学分析

本文是《分析试验室》定期评述中“电化学分析”第二篇和“离子选择电极”第三篇评述文章,它第一次将上述两课题合并为“电化学分析”课题。它对1987～1990年间(其中离子选择电极为1989～1990年)国内电化学分析的进展作了全面评述。内容包括:基础理论研究、极谱与伏安分析、溶出分析、化学修饰电极、液-液界面电化学、色谱电化学与流动注射分析检测、光谱电化学、离子选择电极、库伦分析及其他分析方法     

离子选择电极测定金的评述

综述了1976至1987年期间有关金离子选择电极的研究极道,引用文献39篇。     

五氯苯酚离子选择电极的研制

本文报道以三庚基十二烷基铵与三氯苯酚离子缔合物为电极活性物制备的PVC膜五氯苯酚离子选择电极。该电极具有Nernst响应范围宽2×10~(-5)M～1×10~(-1)M、灵敏度高.斜率S为60、检测下限低5×10~(-6)M、选择较好、响应时间短等特点、且电极连续工作电势读数稳定性好等优点。适用于自动监测及电位滴定分析。     

Thin layer coulometric determination of nitrate in fresh waters

A nitrate ion-selective electrode (ISE) employing a permeable tubular membrane impregnated with a conventional ISE cocktail has been used successfully in the coulometric analysis of nitrate in fresh waters. The liquid ISE membrane comprising a nitrate ionophore [tridodecylmethylammonium nitrate (TDMAN)], lipophilic electrolyte [tetradodecyl-ammoniumtetrakis(4-chlorophenyl)borate (ETH 500)] and plasticizer [bis(3-ethyl-hexyl)sebacate (DOS)] was supported on a porous polypropylene tube. Coulometric analysis with the tubular membrane ISE showed that nitrate could be detected in the range 10–100 μM with a precision of 2.3% relative standard deviation (RSD), limit of detection of 1.1 μM and relative accuracy of 4.4% compared to a certified reference material (CRM) Lake sample.     

Response of the Iron Chalcogenide Glass Membrane Ion‐Selective Electrode in a Seawater Ligand Mimetic Calibration Buffer

As a continuation of recent mechanistic studies into the influence of seawater ligands on the surface chemistry of the iron chalcogenide glass membrane ion‐selective electrode (ISE), the present study has investigated the response of the iron(III) ISE in a seawater ligand mimetic system to examine its suitability as a calibration medium for the electroanalysis of raw or natural seawater. Significantly, dip method calibrations of the ISE in a mixture of salicylate, ethylene diamine tetraacetic acid (EDTA), ethylene diamine and minor amounts of dissolved iron(III) and copper(II) yielded the expected Nernstian response of 30 mV/decade according to the known ion‐exchange/electron transfer response mechanism of this ISE. Furthermore, ideal Nernstian response of the electrode is also obtained in a continuous flow analysis (CFA) mode, noting that this provides scope for using a hydrodynamic flow regime to minimize the electrode release of iron and the concomitant detection limit of the ISE. Ultimately, repetitive CFA analyses of free iron(III) in raw or natural seawater yielded a free iron(III) level commensurate with the expected inorganic and organic speciation of iron(III) in seawater.     

Conformational analysis of 12-crown-3 and sodium ion selectivity of electrodes based on bis(12-crown-3) derivatives with malonate spacers

A conformational analysis was performed on two crown ethers (12-crown-3 and 12-crown-4) using a combination of semi-empirical and ab initio methods. The lowest conformations of 12-crown-3 and 12-crown-4 were found to have exodentate C_3v and C₂ structure, respectively. In the case of the sandwich-type complexation, the nucleophilic cavity of 12-crown-3 rather than that of 12-crown-4 seemed to be optimal for complexation with the Na⁺ ion. Four new bis(12-crown-3) derivatives (1–4) were examined as potential sodium ion-selective ionophores in poly(vinylchloride) (PVC) membrane electrodes. The ion-selective electrode (ISE) based on di(1,5,9-trioxacyclododecanylmethyl) 2-dodecyl-2-methylmalonate (1) had the highest selectivity for the sodium ion among the alkali and alkaline earths studied. The sodium ion selectivity of the ISE based on bis(12-crown-3) derivative 1 was superior to that of the ISE based on the bis(12-crown-4) analogue.     

Development of miniaturized potentiometric nitrate- and ammonium selective electrodes for applications in water monitoring

Mobile analysis with potentiometric sensors is well suited for field measurements. Ion-selective electrodes (ISE) based on polymeric membranes for in-situ determination of nitrate and ammonium contents in ground water, drinking water and surface water have been developed. The ISE are integrated in a multisensor module (MSM) for monitoring these ions over longer time intervals. The receptor is a PVC-membrane with tridodecylammonium nitrate (TDDA) for nitrate- and nonactine for ammonium-electrodes as ionophores. As plasticizer dibutylphthalate (DBT) was used. The main parameters for assessing the efficiency of these ISE are presented.     

Development of miniaturized potentiometric nitrate- and ammonium selective electrodes for applications in water monitoring

Mobile analysis with potentiometric sensors is well suited for field measurements. Ion-selective electrodes (ISE) based on polymeric membranes for in-situ determination of nitrate and ammonium contents in ground water, drinking water and surface water have been developed. The ISE are integrated in a multisensor module (MSM) for monitoring these ions over longer time intervals. The receptor is a PVC-membrane with tridodecylammonium nitrate (TDDA) for nitrate- and nonactine for ammonium-electrodes as ionophores. As plasticizer dibutylphthalate (DBT) was used. The main parameters for assessing the efficiency of these ISE are presented.     

Electron microprobe analysis of micro amount powder samples: A case study on high purity coal

For the major, minor and trace element analysis of the inorganic compounds of a Ruhr-Saar coal different preparation techniques are investigated with X-ray fluorescence analysis, electron microprobe and classical wet chemical methods minimizing sample weight at standard preparation times and analytical accuracies. Considering accuracy as well as preparation efforts, determinations by electron microprobe on small sample amounts (<50 mg) proved to be superior to the other methods.Abbreviations AAS atomic absorbtion spectrometry - EMA electron microprobe analysis - IC ion chromatography - ISE ion sensitive electrode - PHOT photometry - WCA wet chemical analysis - XRF X-ray fluorescence analysis - LTA low temperature plasma ashing - HTA high temperature ashing - l.o.i. loss on ignition     

集成微管路离子选择电极功能块研究

本文对微型管状离子选择电极在流动条件下的电化学特征进行了研究,并设计了新的集成微管路离子选择以电极功能块。用此微型装置测定了土壤、血清、水和药物中的K~+、Na~+、pH、Cl~-、F~-、阿托品、东茛菪碱,并和各种标准方法作了比较,获得满意分析结果。     

叠层型串联ISE的电分析化学性能与Nernst倍增效应

设计了多元叠层型串联ISE,结构紧凑,组装简便,适用于微体积样液分析。对四元叠层型串联ISE的试验表明:与现行ISE比较,其线性响应斜率、测定精密度与灵敏度均增大4倍,但响应速度、选择性系数与检测下限不变。     

Response of a copper(II) and iron(III) ion-selective electrode bielectrode array in saline media

A bielectrode array comprising a jalpaite membrane (i.e., Ag_1.5Cu_0.5S) copper(II) ion-selective electrode (ISE) and chalcogenide glass membrane (i.e., Fe_2.5(Se₆₀Ge₂₈Sb₁₂)_97.5) iron(III) ISE has been assembled by individually wiring each solid-state sensor into a single electrode body. Furthermore, a dual metal ion buffer calibration standard incorporating copper(II) and iron(III) coordinating ligands to regulate the levels of free copper(II) and iron(III) in the buffer has been developed to enable simultaneous calibration of the bielectrode ISE array. In this work, the bielectrode ISE array has been employed in the continuous flow analysis (CFA) of free copper(II) and iron(III) in seawater media. It is shown that the individual electrodes displayed Nernstian response in the metal ion buffer calibration standard over a wide dynamic range (viz., 10⁻¹⁵ to 10⁻⁵ M aCu²⁺ and 10⁻²¹ to 10⁻¹¹ M aFe³⁺), and the results of repetitive CFA analyses of free copper(II) and iron(III) in seawater are commensurate with the typical values found in coastal seawater samples. Clearly, the bielectrode ISE array may be used in the simultaneous analysis of free copper(II) and iron(III) in seawater without fear of cross-interference between the solid-state sensors.     

Characterization of home-made silver sulphide based iodide selective electrode

Polycrystalline silver sulphide/silver iodide ion selective electrodes (ISEs) with four different compositions, 9:1, 2:1, 1:1, 1:9 Ag₂S-AgI mole ratios, have been fabricated in the laboratory and characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). X-ray diffraction studies show the presence of Ag₃SI, Ag₂S and AgI crystalline phases in the electrode material. The electrode surfaces have been found to become smoother and lustrous with increasing percentage of silver sulphide in silver iodide. ISE 1:1, ISE 2:1 and ISE 9:1 all responded in Nernstian manner with slopes of about 60 mV/decade change in iodide ion concentration in the linear range of 1 × 10⁻¹ to 1 × 10⁻⁶ M while ISE 1:9 showed sub-Nernstian behavior with slope of about 45 mV up to the concentration 1 × 10⁻⁵ M. Two capacitive loops, one corresponding to the charge transfer process at metal electrode and the back contact and a second loop corresponding to the charge transfer process at membrane-electrolyte interface have been observed at high and low frequency ranges, respectively. Mott-Schottky analysis shows that the materials are n-type semiconductors with donor defect concentrations in the range of 5.1 × 10¹⁴ to 2.4 × 10¹⁹/cm³.