微机化钾钠测试仪

本文报道设计了微机化的血中钾、钠含量测试仪。该仪器采用FIA-ISE技术,以Z-80CPU为智能部件,可自动完成分析过程并在数码管上显示当前试验的电极斜率及分析结果。仪器A/D转换器采用8位A/D,已证明完全可以满足临床检验要求的精密度和准确度,降低了仪器成本。分析方法简便,快速,可靠,已用于质控血清和人体血清的分析,其分析结果与常规分析方法相一致。     

用离子选择电极测定氧化铍中的钾、钠

用离子选择电极测定氧化铍中的钾、钠,与常用的火焰光度法相比,不仅方法简便,而且能避免大量剧毒的铍蒸汽排入空气中,大大改善了分析条件,减小空气污染。 1.实验结果: (1)以稀盐酸浸出氧化铍中钾、钠,使之与大量基体得以分离。 (2)以10％乙酰丙酮或磺基水杨酸络合铍,能在较高的pH值下顺利地进行测定;电极响应情况与纯标准溶液相同。钠的测量下限为10~(-5)M,钾的测量下限为10~(-4.5)M。 (3)在实验条件下,分别测得钠电极对钾的选择比为5.1 对铍的选择比为8250,钾电极对钠的     

用离子选择电极指示终点电位滴定钾

本文应用缬氨霉素钾电极、BF_4~-电极及四苯硼根电极作为指示电极,以四苯硼钠直接电位滴定钾,均获得满意结果.终点突跃较明显,pH 适用范围广,用于硅酸盐试样分析具有方法简单、准确度较好等优点.另外用电极测定了四苯硼钾的溶度积,20℃时为2.25×10~(-8),与文献值十分一致.     

离子选择电极自动化分析装置

一、前言仪器分析的发展趋势是自动化测量,以求提高分析速度及效率,获得适时的分析结果以及实现最佳条件控制。六十年代中后期发展起来的离子选择电极分析技术具有设备简单、测量方便、易于实现现场测定及自动化测量等特点,已获得广泛的应用。1968年开始出现采用离子选择电极的自动化分析技术,其基本原理一般都是采用连续流动测量的方法,即用比例泵输送样品及必要的试剂按一定的比例混合,然后送入安装有离子选择电极及参比电极的测量电池进行     

集成微管路钾、钠、氯电极在流动体系中的电化学特征研究

本文描述了由管状流通电极、微型阀、化学管路、采样环、静电和脉冲抑制器组成的集成微管路电位分析系统的制备方法,研究了管状电极在流动状态和静止状态的电化学特征,并用此微型装置测定了土壤、水和血清中钾、钠、氯含量。样品分析结果和火焰光度法、硝酸银容量法有良好的一致性。     

急性心肌梗塞患者头发锌、铜及血清钾、钙、镁含量的变化

对２５例刀性心肌梗塞患者的头发锌、铜及血清钾、钙、镁含量进行了测量分析,结果显示患者中高发锌者占２０％,低发锌者占１２％;８８％患者的发铜含量减少;约１／４患者的血钾浓度轻度升高,１／３患者血钙增多,而血镁降低者较多,占７６％。     

亚微米级叉指型超微带电极阵列的加工和电化学表征

超微电极具有常规电极无法比拟的优良的电化学特性.超微电极包括单超微电极和超微电极阵列,单超微电极响应电流较小,一般仪器难以检测;而超微电极阵列除具有单超微电极的特点外,还能增加测量时的响应电流,有利于仪器检测.其中的叉指型超微带电极阵列(IDA)具有产生-收集效应,可提高检测的灵敏度,实现低浓度测量[1～4].将微电子技术和微细加工技术应用于化学和生物传感技术已引起关注,利用微细加工技术可以实现传感器的微型化、集成化和智能化;减少测量使用的样品量;使传感器的敏感元件具有确定的形状和尺寸,提高测量结果的一致性.本文用多…     

氮掺杂石墨烯与发夹DNA修饰的电极为工作电极-差分脉冲伏安法用于测定多巴胺

将玻碳电极(GCE)打磨至呈镜面,在其表面上滴加氮掺杂石墨烯悬浮液5.0μL,在50℃的红外灯下烘干,制得氮掺杂石墨烯修饰的GCE;然后取5.0μmol·L-1发夹DNA(H DNA)溶液10μL滴涂于氮掺杂石墨烯修饰电极表面,制得氮掺杂石墨烯和H DNA修饰的GCE。用此修饰电极作为工作电极,用差分脉冲伏安法(DPV)测定人体血清中多巴胺(DA)的含量。试验表明:氮掺杂石墨烯和H DNA修饰的电极对DA的电化学氧化具有更好的电催化作用。DA在此修饰电极上的氧化峰电流与其浓度在4.0×10-7～6.0×10-5 mol·L-1内呈线性关系,检出限(3s/k)为6.6×10-8 mol·L-1。测定时用pH 6.5磷酸盐缓冲溶液(PBS)作为支持电解质。分析血清样品时前处理如下:取血清样品2.0mL,加入甲醇4.0mL,离心沉淀。取上清液2.0mL,加入等体积的pH 6.5PBS,充分混匀后供测定。用pH 6.5的PBS配制DA标准溶液系列,利用DPV对DA标准溶液系列进行测定,记录其氧化峰电流值,制作工作曲线。应用此方法分析了人体血清样品并以此样品为基体进行加标回收试验,测得回收率在90.0%～110%之间,测定值的相对标准偏差(n=5)在1.7%～3.7%之间。     

用钙离子选择电极测血清中的总钙——两种钙电极及几种测量技术的比较

测定血清中的钙,对许多疾病的诊断具有重要意义。因测定其中游离的钙离子含量很难测准,故测定总钙含量的方法仍被采用。目前国内采用EDTA滴定目视指示终点,终点不明显,误差较大。文献介绍在酸性下使血清中的总钙全部成为游离的钙离子,用直接电位法测总钙。本文中将中性载体(ETH1001)及磷酸醋两种钙电极,使用几种测量技术测定血清中的总钙,进行比较。ETH1001钙电极比磷酸酯钙电极性能优良,表现在电极电位稳定性     

AIA-3型离子选择性电极自动分析仪的研制

同其它分析技术在地球化学分析中的应用一样,离子选择电极分析方法的发展趋势也是自动化测量,以求提高分析速度及效率,获得适时的分析结果及实现最佳条件控制。离子选择电极自动化分析技术发展是比较快的,Babcock等人在连续流动测量技术中做了较多的工作,Ruzicka研究的流动注射分析进一步提高了分析速度,近年来又出现了采用取样间断分析及应用标准加入法的自动分析技术以及采用电子计算机的标准加入拟合技术。国内谢声洛同志研制的离子选择电极自动分析装置和张丽珠等同志研制的离子选择电极差示测量连续自动分析仪显示我国在     

Solid-state electrode with a Cu(I)-based membrane hydrophobised by PTFE for the measurement of Cu2+ and I−

The preparation of CuI + Ag₂S and Cu₂[HgI₄] + Ag₂S membranes hydrophobised by PTFE is described. The pressed membranes mounted in a multi-purpose “all-solid-state” electrode body have been examined as electrochemical sensors for Cu²⁺ and I^? ions. For the electrode with (CuI + Ag₂S + PTFE)-membrane experimental slopes of 29 mV(pCu)^?1 and 62 mV(pI)^?1 were obtained, in good agreement with the theoretical values. For practical measurement in solutions where both Cu²⁺ and I^? can be present, the investigated electrode offers certain advantages in comparison with a commercial Cu-ISE.     

Ion-selective electrode for measuring low Ca2+ concentrations in the presence of high K+, Na+ and Mg2+ background

In this work, ion-selective electrodes for calcium ion were investigated. Two ionophores were used in the membranes: ETH 1001 and ETH 129. An internal filling solution buffered for primary ion was used that allowed the lower detection limit to be decreased down to 10^−8.8 M. Theoretical and experimental electrode characteristics pertaining to both primary and interfering ions are discussed. Better behavior was obtained with the electrode prepared with ETH 129 in the membrane. This electrode would be the most likely candidate for obtaining a low Ca²⁺ detection limit in measurements performed with high K⁺, Na⁺, Mg²⁺ background, which is found inside the cells of living organisms, for example. The potentiometric response of the electrode in solutions containing main and interfering ions is in good agreement with simulated curves obtained using the Nernst–Planck–Poisson (NPP) model.     

检测痕量Hg~(2+)的DNA电化学生物传感器

通过自组装方法将修饰有二茂铁基团的富T序列DNA分子(DNA-Fc)固定在金电极表面,得到了一种基于DNA修饰电极的电化学汞离子(Hg2+)传感器.当溶液中有Hg2+存在时,Hg2+可与修饰电极上DNA的T碱基发生较强的特异结合,形成T-Hg2+-T发卡结构,使DNA分子构象发生改变,其末端具有电化学活性的二茂铁基团远离电极表面,电化学响应随之发生变化.示差脉冲伏安法(DPV)结果显示:DNA末端二茂铁基团的还原峰在0.26V(vs饱和甘汞电极(SCE))附近,峰电流随溶液中Hg2+浓度的增加而降低;Hg2+浓度范围在0.1nmol·L-1-1μmol·L-1时,电流相对变化率与Hg2+浓度的对数呈现良好的线性关系.该修饰电极对Hg2+的检测限为0.1nmol·L-1,可作为痕量Hg2+检测的电化学生物传感器.干扰实验也表明,该传感器对Hg2+具有良好的特异性与灵敏度.     

The advantage of using carbon nanotubes compared with edge plane pyrolytic graphite as an electrode material for oxidase-based biosensors

Carbon nanotubes (CNTs) are promising materials for use in amperometric biosensors. The defect sites at their ends, and on their sidewalls, are considered to be edge plane-like defects and show high electrocatalytic activity toward several biological molecules. However, electrocatalytic activity toward H(2)O(2) has not been compared among bamboo-structured CNTs (BCNTs), which have many defect sites; hollow-structured CNTs (HCNTs), which have few defect sites; edge plane pyrolytic graphite (EPG); and traditional glassy carbon (GC). The advantages of using CNTs in electrodes for biosensors are still equivocal. To confirm the utility of CNTs, we analyzed the electrochemical performance of these four carbon electrodes. The slope of the calibration curve for H(2)O(2) at potentials of both +0.6 V and -0.1 V obtained with a BCNT paste electrode (BCNTPE) was more than 10 times greater than the slopes obtained with an HCNT paste electrode and a GC electrode, reflecting the BCNT's larger number of defect sites. Although the slope with the EPG electrode (EPGE) was about 40 times greater than that with BCNTPE at +0.6 V, the slopes with these two carbon electrodes were nearly equivalent at -0.1 V. EPGE demonstrated excessive electrochemical activity, detecting currents on the basis of consumption of oxygen and oxidation of ascorbic acid, even at -0.1 V. In contrast, BCNTPE could dominantly detect a cathodic current for H(2)O(2) at -0.1 V, even when interfering molecules were added. BCNTPE possesses appropriate electrochemical activity and is an effective electrode materials for developing interference-free oxidase-based biosensors operated by the application of an appropriate potential.     

Electrochemical sensor for Cd2+ and Pb2+ detection based on nano-porous pseudo carbon paste electrode

An electrochemical sensor based on self-made nano-porous pseudo carbon paste electrode (nano-PPCPE) has been successfully developed, and used to detect Cd²⁺ and Pb²⁺. The experimental results showed that the electrochemical performance of nanoPPCPE is evidently better than both glassy carbon electrode (GCE) and pure carbon paste electrode (CPE). Then the prepared nano-PPCPE was applied to detect Cd²⁺ and Pb²⁺ in standard solution, the results showed that the electrodes can quantitatively detect trace Cd²⁺ and Pb²⁺, which has great significance in electrochemical analysis and detection. The linear ranges between the target ions concentration and the DPASV current were from 0.1–3.0 μmol/L, 0.05–4.0 μmol/L for Cd²⁺ and Pb²⁺, respectively. And the detection limits were 0.0780 μmol/L and 0.0292 μmol/L, respectively. Moreover, the preparation of the nano-PPCPE is cheap, simple and has important practical value.     

Mn2+浓度对钒液流电池正极液的电化学性能影响

电解液中金属离子会影响钒液流电池的电化学性能。本文采用循环伏安法和电化学阻抗谱研究了正极液中Mn2+浓度对V髨/V(Ⅳ)电对的氧化还原过程影响规律,发现Mn2+在正极液中没有发生副反应,但严重影响V髨/V(Ⅳ)的反应活性、电极反应可逆性、离子扩散与电荷转移反应等电化学性能。循环伏安测试结果表明Mn2+浓度为0.04-0.13 g.L-1时,V髨/V(Ⅳ)电对电极反应可逆性和反应活性较高,钒离子扩散系数由参照溶液中的8.89×10-7-1.098×10-6增大至1.302×10-6-1.800×10-6 cm2.s-1,提高了-60%;电化学阻抗测试结果表明Mn2+浓度为0-0.04 g.L-1时,V髨/V(Ⅳ)电对电极反应阻抗和界面阻抗均较参照溶液中的增加不明显,但当Mn2+浓度增至0.07 g.L-1时,上述阻抗值较参照溶液增大了25%-28%。基于二者结果,Mn2+对电极反应有不同程度的负面影响,但是适当的Mn2+浓度有利于钒离子的扩散。     

A remeasurement of the products for electron recombination of N2H+ using a new technique: no significant NH+N production

A remeasurement of the product distribution from dissociative electron-ion recombination (DR) of N2H+ has been made using a new technique. The technique employs electron impact to ionize the neutral products prior to detection by a quadrupole mass analyzer. Two experimental approaches, both using pulsed gas techniques, isolate and quantify the DR products. In one approach, an electron-attaching gas is pulsed into a flowing afterglow to transiently quench DR. Results from this approach give an upper limit of 5% for the NH+N product channel. In the second approach, the reagent gas N2 is pulsed. The absolute percentages of products were monitored versus initial N2 concentration. Results from this approach also give an upper limit of 5% for NH+N production. This establishes that N2+H is the dominant channel, being at least between 95 and 100%, and that there is no significant NH production contrary to a recent storage ring measurement that yielded 64% NH+N and 36% N2+H. Possible reasons for this dramatic difference are discussed.     

Elimination of the helium requirement in high-field asymmetric waveform ion mobility spectrometry (FAIMS): beneficial effects of decreasing the analyzer gap width on peptide analysis

Cylindrical geometry high-field asymmetric waveform ion mobility spectrometry (FAIMS) focuses and separates gas-phase ions at atmospheric pressure and room (or elevated) temperature. Addition of helium to a nitrogen-based separation medium offers significant advantages for FAIMS including improved resolution, selectivity and sensitivity. Aside from gas composition, ion transmission through FAIMS is governed by electric field strength (E/N) that is determined by the applied voltage, the analyzer gap width, atmospheric pressure and electrode temperature. In this study, the analyzer width of a cylindrical FAIMS device is varied from 2.5 to 1.25 mm to achieve average electric field strengths as high as 187.5 Townsend (Td). At these electric fields, the performance of FAIMS in an N(2) environment is dramatically improved over a commercial system that uses an analyzer width of 2.5 mm in 1:1 N(2) /He. At fields of 162 Td using electrodes at room temperature, the average effective temperature for the [M+2H](2+) ion of angiotensin II reaches 365 K. This has a dramatic impact on the curtain gas flow rate, resulting in lower optimum flows and reduced turbulence in the ion inlet. The use of narrow analyzer widths in a N(2) carrier gas offers previously unattainable baseline resolution of the [M+2H](2+) and [M+3H](3+) ions of angiotensin II. Comparisons of absolute ion current with FAIMS to conventional electrospray ionization (ESI) are as high as 77% with FAIMS versus standard ESI-MS.     

Electrochemical sensor for Cd2+ and Pb2+ detection based on nano-porous pseudo carbon paste electrode

An electrochemical sensor based on self-made nano-porous pseudo carbon paste electrode (nano-PPCPE) has been successfully developed, and used to detect Cd²⁺ and Pb²⁺. The results showed that the electrodes can quantitatively detect trace Cd²⁺ and Pb²⁺, and with satisfied limit of detection, which has great significance in electrochemical analysis and detection.     

Electrochemical Determination of Cd2+ and Pb2+ Using NSAID‐mefenamic Acid Functionalized Mesoporous Carbon Microspheres Modified Glassy Carbon Electrode

This paper describes the electrochemical behaviors of Cd²⁺ and Pb²⁺ on the proposed mesoporous carbon microspheres/mefenamic acid/nafion modified glassy carbon electrode (MC/MA/Nafion/GC) studied by square wave anodic stripping voltammetry (SWASV). The prepared material is characterized by XRD, SEM, FTIR, RAMAN and BET analysis. Experimental parameters, such as the deposition potential and time, the pH value of buffer solution were optimized. Under the optimized conditions, the electrode responded linearly to Cd²⁺ and Pb²⁺ in the concentration range from 50 to 300 nM, and the detection limits were 24.2 and 11.26 nM respectively. The sensitivity determined was 0.0623 μA/nM (Cd²⁺) and 0.192 μA/nM (Pb²⁺). Multiple metal ion detection with clear demarcation of peaks was produced by the electrode. Moreover, the modified electrode has possessed good selectivity and reproducibility of Cd²⁺ and Pb²⁺ detection. We also investigated the interference of various anions and surfactants for the detection of Cd²⁺ and Pb²⁺ ions. Finally the modified electrode was used to detect the presence of metal ions in practical samples and the results obtained are comparatively good with respect to AAS.