铋膜电极电位溶出法测定痕量铅、镉、锌

研究了用铋膜电极替代汞膜电极测定痕量重金属元素铅、镉和锌的电位溶出法。实验了同位镀铋膜及测定重金属特别是痕量铅的条件。实验结果表明：铅、镉、锌在铋膜电极上可得到灵敏的电位溶出峰，峰高和溶出电位与汞膜电极法相近，使用铋膜电极可避免使用汞电极带来的环境污染。利用铋膜电极电位溶出法测定了水样及血样中痕量铅的含量。     

铋膜电极微分电位溶出法测定生物材料中痕量铅

研究了镀铋膜电极替代镀汞膜电极痕量铅的微分电位溶出分析法(DPSA)。考察并优化了同位镀铋膜测定铅的条件。结果表明,在HAc-NaAc(pH=4.4)介质中,铅可在镀铋膜电极上得到灵敏的微分电位溶出峰;利用标准加入法对人尿及血中痕量铅进行了测定。本法避免了镀汞膜电极对人体健康及环境的危害。     

阳极溶出伏安法测定工业废水中痕量铅镉

玻碳汞膜电极阳极溶出伏安法测定铅镉已有人作了工作,本文将玻碳电极导线的汞接头改为镀铜焊接头,克服了使用过程中因电极内阻变化引起的异常现象及汞蒸气逃出对环境的污染,将通用的同位镀汞法改为先镀汞后富集,减少了例行分析中有毒汞盐的用量并提高了测定结果的精度。本法选取0.2MHAc-0.2MNaAc为基底溶液,氮气作除氧剂兼搅拌器,所得铅镉溶出伏安曲线的峰电位分别     

铋膜电极微分电位溶出法测定环境样品中生物可利用镉

建立了环境样品中生物可利用镉的镀铋膜电极微分电位溶出分析法（DPSA）,考察了同位镀铋膜测定镉的条件。结果表明在HAc—NaAc介质中镉可在镀铋膜电极上得到灵敏的微分电位溶出峰（V=-0．84V）,最低检出质量浓度为0．6μg／L,结合3步连续萃取,利用标准加入法对环境样品中的生物可利用镉进行测定,相对标准偏差2．3％～4.1％,加标回收率97％～104％。     

流动注射-示差脉冲阳极溶出伏安法中壁喷玻碳汞膜电极表面状态研究

通过显微观察,研究了在流动注射一示差脉冲阳极溶出伏安法中,使用壁喷玻碳电极时,在不同的预镀汞膜条件下,在电极表面上形成的汞膜的状态。并获得了适宜的预镀汞膜条件。适宜的预镀汞膜条件为:。     

玻璃石墨金膜电极电位溶出法测定锡

目前电位溶出法常用的工作电极为汞膜电极,常用的氧化剂为溶解氧或汞(Ⅱ)和铬(Ⅵ)。在伏安溶出法中,采用金膜电极仅用于碲、砷、汞、锗等离子的测定,在电位溶出法中也有报导,但就地镀金膜电极电位溶出法尚未见记载。我们经过研究,成功地采用就地镀金的金膜电极对铜、铋、锑、铅进行了测定,蓝对该方法的机理进行了定量推导和探讨。本文进一步用就地镀金膜电极对锡进行了测定,溶液中的Sn(Ⅳ)和Sn(Ⅱ)首先被还原富集于金膜     

铋膜电极溶出伏安法测定食品中痕量重金属

以铋膜电极为工作电极,采用微分脉冲阳极溶出伏安法直接测定食品样品中痕量铅、镉和锌。在富集电位-1.4V,富集时间180s,铋膜质量浓度150μg·L-1的条件下,铋膜电极对铅、镉和锌的氧化溶出具有良好的电化学响应。铅(Ⅱ)、镉(Ⅱ)和锌(Ⅱ)的质量浓度在5.0~40μg·L-1的范围内与其阳极溶出峰电流呈线性关系,铅(Ⅱ)、镉(Ⅱ)和锌(Ⅱ)的检出限(3S/N)分别为0.80,0.65,0.58μg·L-1。对25μg·L-1铅(Ⅱ)、镉(Ⅱ)和锌(Ⅱ)溶液用铋膜电极连续测定15次,相对标准偏差分别为6.2%,5.1%,7.1%。方法应用于食品中痕量重金属的测定,测定结果与石墨炉原子吸收光谱法的测定值相符。     

75—3A型汞膜电极快速极谱仪

厦门大学化学系与厦门第二分析仪器厂试制成功75-3A型汞膜电极快速极谱仪。该仪器应用集成电路装置。仪器包括线性扫描电路、电极系统和记录电流部分。用两只运算放大器作为线性扫描电路和电流放大器。铂球镀银沾汞的汞膜电极代替滴汞电极作常规极谱分析,也可用为溶出分析。用此种电极和仪器在有关单位按常规极谱分析已用于铜合金中的铅和锌,矿物中的铜、铅、镉和锌,铝合金中铋、铜和铅的测定;借溶出法已用于海水痕量铜、镉和锌,二氧化锆中痕量铜、     

利用碘离子增感效应和金电极导数阳极溶出法研究铜、铅和镉的同时测定

本文使用金电极为工作电极,银-氯化银电极为参比电极,铂电极为对电极,在硫酸-碘化四乙基铵介质中减小了铋对铜的干扰,提高了铅、镉测定灵敏度.用导数阳极溶出法,可同时测定铜、铅和镉,它们的溶出峰电位分别为 0.25,-0.12和-0.27V、检测下限分别可达:铜(Ⅱ)和铅(Ⅱ)0.2ppb,镉(Ⅱ)0.05ppb.在选定的条件下,溶出峰电流与浓度很好地成线性关系.本文还用三角波循环伏安法观察了电极反应过程.     

微分电位溶出法测定白酒中微量铅

应用微分电位溶出法测定白酒中微量铅,测定时采用三电极系统(镀汞玻碳电极,饱和甘汞电极,铂电极)。在pH2.0～5.0酸度条件下,铅(Ⅱ)在-1.10V预富集60s,在-0.10～-0.90V区间记录溶出电位,铅(Ⅱ)的溶出电位在-0.44V。铅(Ⅱ)的溶出峰高与铅(Ⅱ)浓度在0～10μg·L-1区间内呈线性关系。方法的检出限为0.2ng·ml-1,RSD(n=6)为1.17%,回收率为96%,与AAS法作比较,结果一致。     

Anodic Stripping Voltammetry Determination of Pb(II) and Cd(II) at a Bismuth/Poly(aniline) Film Electrode

Abstract

A novel voltammetric method—anodic—using a bismuth/poly(aniline) film electrode has been developed for simultaneous measurement of Pb(II) and Cd(II) at low µg L^?1 concentration levels by stripping voltammetry. The results confirmed that the bismuth/poly(aniline) film electrode offered high‐quality stripping performance compared with the bismuth film electrode. Well‐defined sharp stripping peaks were observed for Pb(II) and Cd(II), along with an extremely low baseline. The detection limits of Pb(II) and Cd(II) are 1.03 µg L^?1 and 1.48 µg L^?1, respectively. The bismuth/poly (aniline) electrode has been applied to the determination of Pb(II) in tap water samples with satisfactory results.     

Bismuth Film Voltammetric Sensor on Pyrolyzed Photoresist/Alumina Support for Determination of Heavy Metals

Voltammetric sensors based on bismuth film electrodes are an attractive alternative to other sensors for application in electroanalysis of heavy metals. Bismuth film electrodes can be formed by a similar method on the same substrates as mercury. These systems were used most frequently for simultaneous determination of heavy metals such as Pb, Cd and Zn by anodic stripping voltammetry. Our voltammetric sensor was fabricated on an alumina substrate. A photoresist film prepared by pyrolysis of positive photoresist S‐1813 SP15 on the alumina substrate was used as an electrode support for bismuth film deposition. The influence of the Nafion membrane on the measurement sensitivity of the sensor and mechanical stability of the bismuth film were investigated. The sensor was successfully applied for determination of Pb, Cd and Zn in an aqueous solution in the concentration range of 0.2 to 10 µg L^?1 by square wave anodic stripping voltammetry on an in‐situ formed bismuth film electrode with Nafion‐coating. Parameters of the sensor such as sensitivity, linearity, detection limit, repeatability and life‐time were evaluated. In the best case, the detection limits were estimated as 0.07, 0.11 and 0.63 µg L^?1 for Pb, Cd and Zn, respectively. Finally, the applicability of the sensor was tested in analysis of Pb, Cd and Zn in real samples of tap and river water using the method of standard additions.     

Digestion-free determination of heavy metals (Pb, Cd, Cu) in honey using anodic stripping differential pulse voltammetry and potentiometric stripping analysis

Experiments have been carried out to assess the potential of differential pulse voltammetry and potential stripping analysis for determining Pb, Cu and Cd directly in dissolved honey samples using a flow-through cell. With the hanging mercury drop electrode Pb alone can be determined only if the electrode is first modified in-situ with Triton X 100 to increase the separation between the Pb peak and a broad, interfering adsorption peak which overlaps the Cu peak. If the (more sensitive) thin film mercury electrode is used the interference encountered is less so also Cu and Cd can be determined. With potentiometric stripping analysis Cu and Pb can be determined using normal procedures. The determination of Cd, however, can only be carried out if the concentration of the oxidizing agent [Hg(II)] in solution is decreased. A good agreement has been obtained between the values found and those obtained after high pressure digestion of the samples.     

Bismuth‐Coated Iridium Microwire Electrode for the Determination of Trace Metals by Anodic Stripping Voltammetry

This work reports the utility of an iridium microwire plated in situ with a bismuth film for the simultaneous determination of Pb(II) and Cd(II) by square‐wave anodic stripping voltammetry (SWASV). The experimental variables (concentration of the bismuth plating solution, preconcentration potential, accumulation time) were investigated. The limit of detection was 1 µg L^?1 for Pb(II) and 1.5 µg L^?1 for Cd(II) (at 300 s of preconcentration) and the % relative standard deviations were lower than 4.9 % and 5.5 %, respectively, at the 20 µg L^?1 level (n=8). In addition, a study was made of coating the iridium‐based bismuth‐film microsensor with a film of Nafion for operation in the presence of surfactants. Finally, the electrode was applied to the determination of Pb(II) and Cd(II) in wastewater and tapwater samples.     

Ultrasensitive Voltammetric Detection of Trace Lead(II) and Cadmium(II) Using MWCNTs‐Nafion/Bismuth Composite Electrodes

Multiwall carbon nanotubes were dispersed in Nafion (MWCNTs‐NA) solution and used in combination with bismuth (MWCNTs‐NA/Bi) for fabricating composite sensors to determine trace Pb(II) and Cd(II) by differential pulse anodic stripping voltammetry (DPASV). The electrochemical properties of the MWCNTs‐NA/Bi composites film modified glassy carbon electrode (GCE) were evaluated. The synergistic effect of MWCNTs and bismuth composite film was obtained for Pb(II) and Cd(II) detection with improved sensitivity and reproducibility. Linear calibration curves ranged from 0.05 to 100 μg/L for Pb(II) and 0.08 to 100 μg/L for Cd(II). The determination limits (S/N=3) were 25 ng/L for Pb and 40 ng/L for Cd, which compared favorably with previously reported methods in the area of electrochemical Pb(II) and Cd(II) detection. The MWCNTs‐NA/Bi composite film electrodes were successfully applied to determine Pb(II) and Cd(II) in real sample, and the results of the present method agreed well with those of atomic absorption spectroscopy.     

铋膜修饰玻碳电极伏安法测定微量铅(Ⅱ)

以铋膜修饰玻碳电极为工作电极,采用阳极溶出伏安法对微量Pb(Ⅱ)进行测定。考察了铋离子浓度、支持电解质pH、沉积时间等因素对测定的影响。实验结果表明,铋膜修饰电极对痕量Pb(Ⅱ)具有良好的电化学响应。在实验选定条件下,Pb(Ⅱ)在10～260!g/L范围内与峰电流呈良好的线性关系,检出限为1.98!g/L。用同一支铋膜电极对50!g/L Pb(Ⅱ)平行测定10次,相对标准偏差(RSD)为2.82%。该电极可应用于井水中铅的测定。     

以镍铬合金为基体的铋膜电极的构建及其应用

采用循环伏安法以镍铬合金为基体构建了铋膜/镍铬合金电极,以扫描电镜表征其表面形貌,利用线性扫描伏安法研究了Pb(II)、Cd(II)在该电极上电化学行为。结果表明:在0.20 mol/L HAc-NaAc缓冲溶液(pH4.5)中,该电极对Pb(II)、Cd(II)离子有较好的电催化活性,Pb(II)、Cd(II)的阳极溶出峰电流与其浓度分别呈良好的线性关系,检出限分别为6.39μg/L和3.52μg/L。     

Silver Amalgam Film Electrode of Prolonged Application in Stripping Chronopotentiometry

The utility of the cylindrical silver‐based mercury film electrode of prolonged analytical application in stripping chronopotentiometry (SCP) was examined. This electrode allowed us to obtain good reproducibility of results owing to the special electrode design, which enables regeneration of the thin layer before each measurement cycle. The accessible potential window in KNO₃ (pH 2), acetate and ammonia buffers was defined, and the optimal conditions (i.e., stripping current, deposition potential and deposition time) for the determination of Cd and Pb traces were selected. The detection limits, obtained for an accumulation time of 60 s, were 0.023 μg/L for Cd and 0.075 μg/L for Pb. The response increases linearly with Cd, Pb and Zn concentration, up to at least 100 μg/L. It was also shown that the proposed procedure ensures excellent separation of the In and Tl, Pb and Tl or the In and Cd signals. The method was tested with dolomite and lake sediment samples, and good agreement with reference values was achieved. The obtained results showed good reproducibility (RSD=5–6%) and reliability.     

电位溶出法测定铅和镉

重金属铅和镉元素在环境中普遍存在并可长期蓄积,是不可降解的环境污染物,常危害人体健康.建立快速准确的测定方法具有实际意义[1].     

Simultaneous and Sensitive Detection of Cd(II) and Pb(II) Using a Novel Bismuth Film/Ordered Mesoporous Carbon‐molecular Wire Modified Graphite Carbon Paste Electrode

An electrochemical sensor for the simultaneous and sensitive detection of Cd(II) and Pb(II) is proposed on the basis of square‐wave anodic stripping voltammetry (SWASV) experiments using a novel bismuth film/ordered mesoporous carbon‐molecular wire modified graphite carbon paste electrode (Bi/OMC‐MW/GCPE). Ordered mesoporous carbon (OMC) and molecular wire (MW) (diphenylacetylene) were used as the modifier and binder, respectively. The Bi/OMC‐MW/GCPE was prepared with the addition of graphite powder, OMC and DPA at the ratio of 2 : 1 : 1. The electrochemical properties and morphology of the electrode were characterized by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), SWASV and scanning electron microscopy (SEM). The parameters affecting the stripping current response were investigated and optimized. The experimental results show that the prepared electrode exhibited excellent electrochemical performance, good electrical conductivity and a high stripping voltammetric response. Under optimized conditions, a linear range was achieved over a concentration range from 1.0 to 70.0 μg/L for both Cd(II) and Pb(II) metal ions, with detection limits of 0.07 μg/L for Cd(II) and 0.08 μg/L for Pb(II) (S/N=3) with the deposition time 150 s. Moreover, the sensor exhibited improved sensitivity and reproducibility compared to traditional CPEs. The fabricated electrode was then successfully used to satisfactorily detect Cd(II) and Pb(II) in real soil samples.