Determination of Lead in Water by Linear Sweep Anodic Stripping Voltammetry (LSASV) at Unmodified Carbon Paste Electrode: Optimization of Operating Parameters

This study presents the elaboration of a simple and cheap electrode made by carbon paste introduced into a cavity of electrode body, and used for the lead traces determination in tap water. A potentiostatic pre-electrolysis at constant voltage enables the reduction of the lead (Pb2+) and the accumulation of the metallic lead at and into the carbon paste;the reoxidation of the Pb (Linear sweep voltammetry) leads to the anodic striping peak. The effect of the main operating parameters on the shape of the peak and the magnitude of the current was examined and their optimal values were determined. Then calibration was achieved and the method was successfully applied (using all the optimized parameters) to the determination of lead in water, with a detection limit of 0.138 μg·L-1. Compared to other methods (ICP-AES for example), the proposed method offers a satisfactory detection limit of the Pb2+ (0.138 μg·L-1) because of the important specific area of the carbon paste electrode, for a significantly lower cost. Besides, there is no observed loss in the electrode answer in terms of peak current, which means that there is no any irreversible steps nor deactivation of the electrode, even after ten successive measurements;only reduction of the lead followed by the deposit oxidation was observed at the electrode.

Determination of Epinephrine Using Poly(Neutral Red)Modified Carbon Fibre Microelectrodes by Anodic Stripping Voltammetry

Poly(neutral red) film modified carbon fibre microelectrodes offer substantial improvement in voltammetric sensitivity and selectivity towards epinephrine (EP). The poly(neutral red) film was electropolymerized by cycling the potential between -0.8 V and +0.8 V. The anodic stripping voltammetric response for EP was found to be dependent on accumulation time and potential. By using a poly(neutral red) film modified carbon fibre microelectrode with a 1 min preconcentration at -1.2 V in biological phosphate buffer solution (pH=7.4), a good linear relationship between the anodic stripping peak currents and EP concentrations was obtained in the range of 2.0×10 -7 ￣ 2.0×10 -5 mol/L. The detection limit was up to 9.0 ×10 -8 mol/L. Moreover, 400 times higher concentrations of vitamin C did not interfere with the measurement of EP. This method was used for determining EP concentrations in epinephrine hydrochloride injection solution with satisfactory results.

Determination of Soil Base－Suluble Se by Anodic Stripping Voltammetry with Aurum Thin－Film Electrode

Determination of soil Se by anodic stripping voltammetry (ASV) with aurum thin-film electrode (ATFE) over-comes the interference of gold peak with selenium peak, and thus has a higher sensitivity with the mininiumdetectable concentration being 0.017 μg/mL, the standard deviation of the measured results less than 0.012 μg/g,the coefficient of variation lower than 10%, and the recovery rate between 86% to 103%. Besides the measurementconditions, the digestion of soil sample was also studied in detail.

Anodic Stripping Voltammetric Determination of Nitrite Using Carbon Paste Electrode Modified with Chitosan

A simple method for anodic stripping voltammetric determination of nitrite using carbon paste electrode modified with biomolecular chitosan, is described. In this method, the electrode is activated electrochemically by scanning 5 replicates over the potential range from +500 to +1400 mV immersing in 0.5 M HCl solution. Following this step, the nitrite sample containing 0.1 M KCl is preconcentrated on the activated electrode at +500 mV for 30 s. The deposited anions are then oxidized by different modes of sweep in the oxidation direction. Chemical and electrical parameters affecting the voltammetric measurements are optimized. The peak current is linear proportional to the NO2- concentration within the range 0.41 - 4.1 μg/ml, with detection limit 0.187 μg/m using differential pulse mode. The relative standard deviation is 0.285% for 2.46 μg/ml (five replicates). No interference is observed due to oxygen dissolved in the sample so that nitrogen purging is not needed in this case. The result obtained by the modified electrode is more accurate and selective than the unmodified electrode.

Gold nanoparticle-based anodic stripping voltammetry detection of transcription factor NF-kB

Transcription factor and sequence specific DNA interactions play important roles in drug genome and transcription diagnosis. Gold nanoparticles show high sensitivity, stability and compatibility for biological molecules as electrochemical intercalators. Here unimolecular hairpin oligonucleotides were self-assembled onto Au electrode surface and elongation on solid phase was carried out to double strand oligonucleotides with transcription factor NF-r,13 binding site. Gold nanoparticle-catalyzed Ag deposition was detected by anodic stripping voltammetry （ASV） for NF-kB binding. It was indicated that this method for sequence specific DNA binding protein detection shows pronounced specificity, sensitivity and we can find application in transcription regulation research, open reading frame characterization and functional gene inspection by this method.

伏安极谱仪测定海水中活性态痕量金属

阳极溶出伏安法是一种可以直接用于海水中痕量金属元素检测分析的有效方法,不仅能够实现多元素同时检测,而且不需要样品预浓缩处理.通过伏安极谱仪,研究了富集电位和富集时间等关键参数对阳极溶出伏安法测定痕量金属铜、铅、镉、锌的影响,对过滤后的海水样品直接进行检测,实现了烟台四十里湾不同站位海水中活性态痕量金属铜、铅、镉、锌的测定,为海水中痕量金属元素的形态分析及生物可利用性研究提供了有效技术手段.

阳极溶出伏安法便携式重金属分析仪性能测试方法研究

阳极溶出伏安法便携式重金属分析仪被广泛应用于水体、土壤、食品、固态物质的重金属含量检测。除镉、铅、铜外,使用该分析仪检测砷、汞、锌、铬、锰、镍、锡、铊、铁、钴、硒、银、碲、金、铋等重金属时,需选择合适的计量性能测试项目及测试方法。同时,JJF 2037-2023《便携式溶出伏安法重金属检测仪校准规范》对测量镉、铅、铜元素的便携式溶出伏安法重金属检测仪的计量特性及校准方法做出了要求。

Automated Determination of Cd^(2+) and Pb^(2+) in Natural Waters with Sequential Injection Analysis Device Using Differential Pulse Anodic Stripping Voltammetry

An electrochemical flow device has been developed for the determination of heavy metal ions(HMI)in water using multiwalled carbon nanotubes(MWCNTs)/Nafion(NA)/Hg electrode,by mean of diff erential pulse anodic stripping voltammetry coupled with sequential injection analysis.The accuracy of the determination was ensured by the great electrical conductivity of MWCNTs and the high adsorption capacity of Hg.NA was used for MWCNTs immobilization for the long-term application of the electrode.The mercury film was cleaned after determination and another one would form during deposition.A lower limit of detection and a wider determination range of Cd^(2+)and Pb^(2+)could be achieved using the automatically analytical device combining with the MWCNTs/NA/Hg-modified electrode.The real-time monitoring of Cd^(2+)and Pb^(2+)in fresh water using this device continued for 10 days.The results indicated that the method was potential for on-site and real-time determination of HMI in water samples.

阳极溶出伏安法测定微量镉实验的课程思政设计

阳极溶出伏安法测定微量镉是一项经典的仪器分析基础实验。然而,该实验项目的传统教学内容较难使学生体会所学知识对实际生产生活的价值,不能有效落实课程思政建设的要求。本文旨在通过对教学内容的创新设计,更好地实现思政育人目标。引导学生对新闻事件、学科发展历史、科学家的故事和行业发展最新动态进行调研与讨论,增加设计性和探索性内容,提高本实验的高阶性。采用实际购得的大米等粮食替代以往预先配制的镉溶液,并采用自己独立制备的汞膜电极替代商业化的极谱仪电极,使学生在巩固实验操作技能的基础上,了解分析仪器的发展及改造方式,并掌握分析化学的基本研究范式。对本实验内容的优化,有助于培养学生的科学精神与科研素养,使学生体会专业知识对解决实际生产生活问题的意义,帮助其树立职业追求目标并养成良好的社会责任意识。

斜削碳纤维束复合微电极研制及ASV法测定人发中微量铅

本文叙述了斜削碳纤维束复合微电极制作方法及其伏安特性。用阳极溶出伏安法测定人发中的铅含量，确定了适宜的实验条件。方法简便、快速、灵敏度高、重现性好。检出限为０．１ｎｇ·ｍＬ－１，线性范围为１．０～２０ｎｇ·ｍＬ－１，相对标准偏差为３．４％。

两步酸化DPASV对乐安江沉积物水提液中铜的毒性形态分析

本文采用两步酸化微分脉冲阳极溶出伏安法(DAM-DPASV)对乐安江沉积物水提液中的铜进行形态分析,并与直接DPASV测试及生物测试(D,magna)结果进行了比较,结果表明:直接DPASV测试因水体中络合剂和表面活性剂的干扰而低估了毒性形态,而两步酸化DPASV较好地反映出了铜的毒性形态.

四种稻米中镉检测方法比较研究

采用石墨炉原子吸收法、固体直接进样电热蒸发原子吸收光谱法、电化学阳极溶出伏安法和X射线荧光光谱法测定稻米中镉含量,对4种定量检测方法的准确度、精密度以及相对误差进行了比较分析。研究结果表明,固体直接进样电热蒸发原子吸收光谱法操作简单,无需化学前处理,单样检测时间在3 min左右,快速高效,精密度良好,可信度高。通过4种检测方法对比,固体直接进样电热蒸发原子吸收光谱法的测试结果准确度高,与国家标准方法相比相对误差多数在±10%以内,重复6次测定的RSD为3.9%,可作为一种新型快速检测稻米中镉的方法,具备方便快速、准确度高、重复性好等优点,在基层可广泛应用。

光亮镀镍液中糖精含量测定的新方法——阳极溶出伏安法(ASV)

糖精作为次级光亮剂在光亮镀镍中得到广泛应用.但糖精在镀液中含量测定一直是个大问题.作者提出在较小电极上阳极溶出伏安法(ASV)测定镀镍液中糖精含量,获得较为满意的结果.

基于三电极的便携式重金属离子检测仪研制与应用

该文研制了一种小型化重金属离子检测仪。该仪器具有高精度、稳定、便携等优点,能够精准输出-2.5~+2.5 V范围内的激励信号,通过调节8种不同的增益,可检测pA~mA范围内的电流,满足痕量重金属离子的检测需求。验证了检测仪的4项硬件参数性能,包括:激励信号输出精度、恒电位电路的稳定性、微小电流检测的准确性以及整体伏安性能测试。电化学性能通过在铁氰化钾溶液中以不同扫描速率的循环伏安实验进行验证,得出峰值电流高度与扫描速率的平方根呈线性关系,相关系数(r^(2))均大于0.99。以未经修饰的丝网印刷金电极作为传感器,采用方波阳极溶出伏安法(SWASV)检测Pb^(2+),得到10~100μg/L质量浓度范围内的校准曲线,检出限达0.295μg/L,且重复性良好。通过与台式电化学分析设备Gamry Reference 600+进行比较,得到近乎一致的校准曲线,r^(2)分别为0.9989和0.9991,体现了所研制仪器的可靠性。该仪器在提供强大的检测性能和可靠性的同时,实现了低成本和便携性,可用于环境水体中重金属离子的现场检测。

基于ZIF金属有机骨架材料的重金属离子电化学传感检测

以NaOH为介导剂,利用直接搅拌法制备了Co、Zn含量不同的ZIF金属有机骨架材料,并将该材料用于重金属离子的电化学检测。利用扫描电子显微镜(SEM)、能量色散谱(EDS)、X射线衍射(XRD)、X射线光电子能谱(XPS)技术对样品的结构和形貌进行了表征,采用差分脉冲阳极溶出伏安法(DPASV)对重金属离子Pb^(2+)和Cd^(2+)进行了电化学传感检测。结果表明,所制备的ZIF金属有机骨架材料表面光滑,呈菱形十二面体形状,其尺寸随锌摩尔分数的增加而减小。Co、Zn的摩尔分数比对所构建的重金属离子电化学传感器的检测性能有很大的影响,在金属源总数为0.6 mmol的前提下,当Co、Zn摩尔分数比为1∶1.5时,电化学传感检测性能最好,对Pb^(2+)和Cd^(2+)的检测限分别达到了28.3 nmol/L和21.2 nmol/L,同时该电化学传感器也表现出较宽的线性检测范围,以及良好的稳定性、重复性和抗干扰性,可用于实际水样中Pb^(2+)和Cd^(2+)的检测。

负载爆米花状铜粒子的植酸掺杂碳纳米管网络用于Hg(Ⅱ)的高灵敏检测

Hg(Ⅱ)易于在生物体内积累,对人类健康和生态环境构成严重威胁,实现Hg(Ⅱ)的灵敏、快速且准确的检测至关重要。以逐步电沉积的方式,先后在丝网印刷碳电极表面修饰植酸掺杂的碳纳米管网络(PACNTnet)和爆米花状铜粒子(popCu),以构建Hg(Ⅱ)电化学传感器。含有丰富含氧官能团和磷酸根的PACNTnet为Hg(Ⅱ)提供了大量的结合位点,而适量Cu(Ⅱ)与Hg(Ⅱ)之间的协同作用实现了电流信号的放大。因此,所制备的电化学传感器对于Hg(Ⅱ)的检测表现出良好的选择性、重现性和稳定性,在Hg(Ⅱ)质量浓度为0.02~2μg/L的线性范围内,传感器灵敏度高达5.51μA/(μg·L^(-1)),检测限低至0.012μg/L。此外,大米和茶叶样品的加标回收实验也获得了良好的回收率,证明了该传感器在实际样品中的应用潜力。

铋纳米粒子/花状碳球电化学传感器的构建及葛根中重金属的检测研究

目的构建基于铋纳米粒子(BiNPs)/花状碳球(FCS)的电化学传感器,用于检测葛根中Cd^(2+)与Pb^(2+)的浓度。方法首先通过管式炉热裂法合成FCS;其次采用化学还原法将BiNPs负载在FCS表面;最后通过滴涂法构建电化学传感器。透射电子显微镜(TEM)和循环伏安法(CV)用于材料的表征。差分脉冲阳极溶出伏安法(DPASV)用于检测Cd^(2+)与Pb^(2+)的浓度。根据DPASV峰电流值大小对实验参数进行优化。结果在最佳实验条件下,Cd^(2+)与Pb^(2+)的峰电流响应值与浓度线性良好,R^(2)分别为0.996和0.997,线性响应范围为5~200μg·L^(-1)。Cd^(2+)与Pb^(2+)的检出限分别为0.45μg·L^(-1)和0.53μg·L^(-1)。该传感器成功用于葛根中Cd^(2+)和Pb^(2+)的检测,加样回收率在92.0%~116.8%内。结论所构建的传感器可用于葛根中Cd^(2+)与Pb^(2+)的检测。

锑原位掺杂SiO_(2)@PDA-Sb复合材料修饰电极用于海水中Zn离子检测

本研究提出了一种用于检测海水中锌离子(Zn^(2+))含量的电化学检测方法。该方法首先应用水热法合成SiO_(2)@PDA-Sb复合材料,然后将该复合材料修饰到玻碳电极上制备SiO_(2)@PDA-Sb-Nafion/GCE,利用差分脉冲阳极溶出伏安法(DPASV)对珠江口海水水样中Zn^(2+)进行测定。研究结果表明,Zn^(2+)在SiO_(2)@PDA-Sb-Nafion/GCE上具有较强的溶出峰。在最优条件下,SiO_(2)@PDA-Sb-Nafion/GCE对Zn^(2+)浓度在1~1000 nmol/L范围内可实现灵敏、准确的检测,Zn^(2+)的检测出限为0.71 nmol/L。加标回收率实验显示Zn^(2+)加标回收率为93.19%~100.12%,表明该方法可应用于现场海水样品Zn^(2+)测定。本方法具有电极制作简单、稳定性和抗干扰性良好,能够提高现有测定方法的检测限和精确度,在现场海水检测痕量Zn^(2+)具有较好的应用前景。

利用汞膜修饰电极对培养基环境下成肌细胞吸收Cu2+的定量分析研究

本文提出针对细胞培养基的特性,通过优化的差分脉冲溶出伏安法测量成肌细胞对铜离子的吸收量。在三电极体系中采用120 mg/L的Hg2+在-0.2 V下对工作电极镀膜,实现检测铜离子最低0.5 ng/mL的浓度变化量,本方法对细胞培养基内铜离子的线性测量范围约为1-150 ng/mL,且溶出峰约在-0.20 V至-0.15 V之间,并具有高度选择性和快速特性。试验结果表明,在初始外加10和50 ng/mL Cu^(2+)的含血清培养基中,成肌细胞3天后对其吸收度分别为15.2和29.6 ng/ml。本文亦讨论了在培养基条件测得的Cu^(2+)溶出峰相对水溶液发生左移的可能机制。

羧甲基壳聚糖基水凝胶修饰电极的制备及其对Cd^(2+)和Pb^(2+)的同时检测研究

制备了羧甲基壳聚糖-多巴胺水凝胶材料并用作电极修饰材料,成功实现了对Cd2+和Pb2+的同时检测。通过采用扫描电子显微镜、傅利叶红外光谱仪和各种电化学技术对材料的形貌及其电化学性质进行了表征。在最优条件下,构建的电化学传感平台对Cd^(2+)和Pb^(2+)的线性检测方程分别为I=0.40×logC(Cd^(2+))+2.10,R^(2)=0.994、I=1.35×logC(Pb^(2+))+2.99,R2=0.993;线性范围分别为0.01~5、0.05~5μmol/L;检出限分别为6、8 nmol/L。该水凝胶修饰电极具有良好的选择性、重现性和稳定性,在实际样品中的添加回收率为96%~106%,相对标准偏差不大于5%,添加回收实验结果令人满意。