生物可利用铅的铋膜电极微分电位溶出法测定研究

研究了镀铋膜电极替代镀汞膜电极的微分电位溶出分析法(DPSA)测定铅的方法,考察了同位镀铋膜测定铅的条件.结果表明,在HAc-NaAc介质中铅可在镀铋膜电极上得到灵敏的微分电位溶出峰,结合三步连续萃取利用标准加入法对城市污泥样品中的生物可利用铅进行测定,避免了镀汞膜电极带来的健康与环境危害,结果较满意.     

多壁碳纳米管-铋膜电极微分电位溶出法测定涂料中的铅

制备了嵌入式多壁碳纳米管膜玻璃碳电极,研究了铅在电极上的电位溶出行为,建立了嵌入式碳纳米管-铋复合膜电极测定铅的微分电位溶出分析法。结果表明:富集电位为-1.1 V,HAc-NaAc(pH=4.60)缓冲溶液中,峰高与铅浓度在0.1～20.0μg/L范围呈线性,检出限为0.5μg/L,对实际样品进行测定,相对标准偏差(RSD)值在3.8%～7.1%之间,回收率在95.2%～98.7%之间。     

同位镀铋丝网印刷电极快速检测水中铅、镉离子

针对水体中生物毒性显著的重金属离子,本文采用丝网印刷电极三电极系统,通过同位镀铋膜阳极溶出伏安法,对水体中铅、镉两种重金属离子实现快速准确定量。结果表明:铅、镉离子在铋膜电极上可以得到灵敏的溶出峰,且铅离子与镉离子的溶出峰面积在0.1 mg/L～0.7 mg/L的浓度范围内呈现良好的线性关系,线性相关系数分别为0.9932、0.9917,检出限分别达0.034 mg/L、0.028 mg/L,样品加标回收率分别为102.51%与91.07%。基于共存离子的干扰特性,重点筛选典型干扰离子,分别研究了氧化性离子与共镀"合金"离子对铅、镉两种金属离子检测稳定性的影响。本方法简单、快速、准确,为突发重金属环境污染事件现场,提供一种可靠的分析方法。     

阳极溶出伏安法测定纯锌、铝中的铜、铅、镉

<正> 测定锌、铝中痕量杂质是鉴定纯度的基础工作。玻璃碳汞膜电极微分脉冲阳极溶出伏安法(DPASV法)已被用于测定水中铜、铅、镉。但是,纯锌、铝中砷、锑、铋、锡等对测定痕量的铜、铅、镉有干扰。利用巯基棉在0.1M盐酸介质中,能定量吸附     

微分脉冲极谱阳极溶出伏安法测定纯银中痕量的铜、铅、镉

银中杂质含量的测定是鉴定纯度的基础工作。玻璃碳汞膜电极微分脉冲极谱阳极溶出伏安法(DPASV法)已用于水中铜、铅、镉的测定,但纯银中痕量铜、铅、镉的测定方法未见报道。以DPASV法测定银中铜、铅、镉时,银产生严重干扰。现用0.1M硝酸的银样消解液,使之在通过巯基棉时银被吸附,铜、铅、镉不被吸附而加以分离,然后再测定铜、铅、镉等。本方法采用0.02M的乙酸钠-硝酸-6×10~(-5)MHg~(2 )底液,同位镀汞,玻璃碳汞膜电极DPASV法检出下限,铜2ppm、铅5ppm、镉2ppm。对纯度为     

用阳极溶出伏安法同时测定微量铅和锡

阳极溶出伏安法可分别测定铅和锡,但同时测定较为困难,这是由于锡易于水解和在介质中形成聚合物;在大多数支持电解质中(如在酸性介质中),铅和锡的溶出电位相近,使两峰重叠。为了同时测定铅和锡,我们参考了Glodowski等的方法,采用国产883型笔录式极谱仪,配用玻碳旋转电极同位镀汞。通过试验,选用适合铅和锡共存下同时测定的底液0.1M草酸-0.1M连苯三酚-5×10~(-5)M汞(Ⅱ)。在此基础上,     

同位镀汞电化学溶出多次半微分电分析法的研究(摘要)

本文提出同位镀汞薄膜电极阳极溶出过程中电流的1.5次和2.5次微分对电极电位曲线的理论,推导出其相应的理论曲线和有关方程,研究了有关特性,并用实验加以验     

铋膜/SDS/三维石墨烯泡沫修饰玻碳电极测定水中铅离子

本文以铋膜/十二烷基硫酸钠/三维石墨烯修饰玻碳电极为工作电极,采用方波阳极溶出伏安法研究了铅离子的电化学测定方法。比较了不同材料修饰时电极性能的差异,探讨了溶液p H值、铋膜厚度、沉积电势、沉积时间等因素对检测信号的影响。实验结果表明,修饰电极检测铅离子的线性范围宽,检出限低,且该电极具有良好的一致性、重现性、稳定性。     

铋膜电极吸附溶出伏安法测定铅的研究

建立了采用铋膜电极应用吸附溶出伏安法测定痕量铅的方法。在含有Pb(II)的0.1 mol·L-1柠檬酸-柠檬酸钠缓冲溶液(pH 6.7)中,于-0.1V搅拌富集,Pb(II)与茜素紫形成络合物而富集于电极表面,然后交换介质至空白底液中,于-0.85 V还原后再进行阳极化扫描,于-0.60 V左右获得一灵敏的铅氧化溶出峰,溶出峰电流与Pb(II)的浓度在1.2×10-8~2.4×10-6 mol·L-1范围内呈良好的线性关系,检出限达6.2×10-9 mol·L-1。方法应用于皮蛋中铅的测定,其加标回收率达到98.0%~122.0%,结果较满意。     

计时电位溶出法测定天麻中的痕量砷

以镀金玻碳电极为工作电极,计时电位溶出法测定天麻中的痕量砷。选择富集电位为-0.45V,溶出低液为3.0 mol/L的硝酸,在+0.14V电位处获得一灵敏的砷(Ⅲ)的二次微分电位溶出峰,且该溶出峰的峰高与砷的质量浓度在2.0～12.0μg/L范围内呈线性关系,方法的检出限(3S/N)为0.96μg/L。方法用于测定天麻中痕量砷的回收率为97.6%～102.4%,RSD为2.7%～3.1%。     

Detection of trace levels of Pb in tap water at boron-doped diamond electrodes with anodic stripping voltammetry

Boron-doped diamond (BDD) electrodes were used to investigate the possibility of detecting trace levels of lead by linear-sweep anodic stripping voltammetry. The low limit of detection (2 nM) is an advantage compared to other electrode materials, and it was found that at low pH values, copper concentrations that are usually present in drinking water do not affect to a large extent the detection of lead. These findings recommend anodic stripping voltammetry at the BDD electrodes as a suitable mercury-free method for the determination of trace levels of lead in drinking water. The results obtained for the lead detection in tap water real samples are in excellent agreement with those found by inductively coupled plasma-mass spectrometry (ICP-MS), demonstrating the practical analytical utility of the method.     

Simultaneous determination of lead, copper and cadmium onto mercury film supported on wax impregnated carbon paste electrode: Assessment of quantification procedures by anodic stripping voltammetry

The deposition and stripping processes of lead and copper and cadmium ions over the wide concentrations range of 1 × 10⁻⁵ to 5 × 10⁻⁹ M, have been studied at mercury film deposited on wax impregnated carbon paste electrode, using cyclic voltammetry, linear sweep anodic stripping voltammetry and differential pulse anodic stripping voltammetry. The carbon paste electrode modified with the mercury film was characterized for its physical and electrochemical properties. The parameters of deposition and stripping processes of the analytes have been investigated using standard solution of the metal ions at various concentrations and different supporting electrolytes and different pH. The linear sweep anodic stripping has been adopted for the determination of analytes at higher concentration whereas the analytes at lower concentrations were determined using DPASV. The DPASV behavior for the ions studied dependent on concentrations of the analyte as well as on the time used in the pre-concentration step. The method developed using standard solutions have been successfully applied for the determination of Cu(II), Pb(II) and Cd(II) in Fin Fish muscles and water samples.     

DL-精氨酸/石墨烯修饰电极测定铅

用循环伏安法制备DL-精氨酸/石墨烯修饰玻碳电极,研究金属铅在修饰电极上的电化学行为。在0.1 mol/L pH=4.5的NaAc-HAc缓冲液中,以DL-精氨酸/石墨烯修饰电极作为工作电极,用循环伏安法测定-1.0~1.0 V处的溶出峰电流。实验结果显示:铅的浓度与溶出峰电流具有良好的线性关系,范围是3.0×10-9~9.0×10-7mol/L,检测限为1.0×10-10mol/L,用于测定金属结果满意。     

Electrochemical behavior of folic acid on mercury meniscus modified silver solid amalgam electrode

Voltammetric behavior of folic acid and folates has been investigated using direct current voltammetry, differential pulse voltammetry and adsorptive stripping differential pulse voltammetry at a mercury meniscus modified silver solid amalgam electrode (m-AgSAE). The optimum conditions have been found for their determination in a 1:9 mixture of methanol and aqueous acetate buffer, with the limit of detection about 0.5 nmol L⁻¹. RSD at this concentration level amounted to less than 4%. Practical applicability of the newly developed method was verified by analysis of three vitamin preparations and of two multivitamin juices.     

Determination of picomolar silver concentrations by differential pulse anodic stripping voltammetry at a carbon paste electrode modified with phenylthiourea-functionalized high ordered nanoporous silica gel

This study introduces the design of an anodic stripping voltammetric (ASV) method for the silver ion determination at a carbon paste electrode (CPE), chemically modified with phenylthiourea-nanoporous silica gel (Tu-SBA-15-CPE). The electroanalytical pro includes two steps: preconcentration of metal ions at an electrode surface, followed by quantification of the accumulated species by differential pulse anodic stripping voltammetric methods. Factors affecting the performance of the anodic stripping were investigated, including the modifier quantity in the paste, the electrolyte concentrations, the solution pH and the accumulation potential or time. The most sensitive and reliable electrode contained 10% Tu-SBA-15 and 90% carbon paste. The accumulation potential and time were set at, −200 mV and 300 s, respectively, and the scan rate at 50 mV s⁻¹ in the scan range of −200 to 700 mV. The resulting electrode demonstrated a linear response over range of silver ion concentration of 8.0-80 pmol/L with detection limit (S/N = 3) of 5 pmol/L. The prepared electrodes were used for the silver determination in sea and tap water samples and very good recovery results were obtained. The accuracy was assessed through recovery experiments and independent analysis by graphite furnace atomic absorption spectrometry.     

Synthesis and characterization of composite Hg-polyaniline powder material

A simple synthesis method is proposed to obtain a composite powder material constituted by polyaniline powder containing mercury droplets closely linked into PANI matrix. ¹⁹⁹Hg solid state NMR spectroscopy indicates that incorporated mercury is in a metallic form and proves a redox reaction between polyaniline (leucoemeraldine form) and an aqueous solution of Hg(I). This composite powder material has been studied by voltammetry with a cavity microelectrode (CME). This electrode appears suitable for characterizing such a material. CME containing Hg-polyaniline (Hg-PANI) powder has been used as an electrochemical microsensor for lead trace analysis by anodic stripping voltammetry of water without electrolyte addition.     

汞膜电极阳极溶出伏安法测定痕量锗的研究

提出了一种以铂基汞膜电极阳极溶出伏安法测定痕量锗的方法,发现在pH 7的酒 石酸缓冲溶液中于-1.20 V和-0.50 V左右出现两个溶出峰。锗的浓度在0.01～1 mg/L范围内 与第一个峰(-1.20 V)有良好的线性关系,检出下限为1×10-9。     

利用超声波阳极溶出伏安法测定痕量汞

以阳极溶出伏安法研究了超声波作用下汞在金电极上的电化学行为,建立了痕量汞的超声波-阳极溶出伏安法。采用超声波增加了汞的溶出峰电流,提高了方法的灵敏度,在优化实验条件下,汞离子浓度在0～25μg/L范围内,线性方程为I=1.08c+0.27,(μg/L,R=0.998),加入标准汞溶液为6μg/L时,测量值的重复性和精确度都在5%以内。常见金属离子一般不干扰,方法简便快速。