碳纤维束汞膜电极二次微分阳极溶出伏安法测定锌中微量铅

本文提出了碳纤维束汞膜电极二次微分阳极溶出伏安法测定锌中微量铅的方法，对溶解氧，扫描速度，电极清洗时间，富集电位和时间及酸度的影响作了讨论。方法的线性范围为１．９－８０μｇ／Ｌ；检测下限达到１．９μｇ／Ｌ；对国家保证参考物质锌样中铅的测定，相对标准偏差和相对误差分别为２．６％和０．６５％，结果令人满意。     

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％。     

A Study of the Determination of Cu(II) by Anodic Stripping Voltammetry on a Novel Nylon/Carbon Fiber Electrode

In this work we report a new electrode material formed by injection‐moulding of a conducting polymer consisting of carbon fibers in a Nylon matrix. This material is highly conductive, inexpensive, easy to mould in different shapes and requires minimal pretreatment. The electrode was tested as a mercury‐free sensor for the trace determination of Cu(II) by anodic stripping voltammetry (ASV). The deposition and stripping behavior of copper on the conducting material was initially studied by cyclic voltammetry and the chemical and instrumental parameters of the determination were investigated. The electrode has been shown to be suitable for the determination of Cu(II) in the range 8 μg L^?1 to 30 mg L^?1 (with deposition times ranging from 30 s to 10 min) with a relative standard deviation of 2.2% (at the 0.5 mg L^?1 level) and a limit of detection of 8 μg L^?1 Cu(II) for 10 min of accumulation (at a S/N ratio of 5). The electrode was, finally, applied to the determination of copper in tap‐water, pharmaceutical tablets and bovine serum with recoveries of 97.4, 94.9 and 93.4%, respectively     

Coulometric Anodic Stripping Voltammetry of Lead at Copper Column Electrode

A flow coulometric electroanalytical system using a copper column electrode with a copper wire inserted into a Nafion tube was developed to determine Pb(II) content based on anodic stripping voltammetry. The electrolysis efficiency of 5 μM Pb(II) was evaluated to be 100.4±4.5 % (n=5) when the length of the copper wire and flow rate of the Pb(II) solution were 50 cm and 0.1 mL min⁻¹, respectively. The amount of electricity due to the re-oxidation of Pb electrodeposited at the copper column electrode was proportional to the concentration of Pb(II) in the range between 0.1 to 100 μM, and the limit of detection for Pb(II) was 0.8 μM for a deposition time of 15 min. Interference from the presence of Cd(II) could be avoided and the selective determination of Pb(II) was successfully achieved by adjustment of the electrodeposition potential.     

Study of Bare and Mercury‐Coated Vibrated Carbon,Gold and Silver Microwire Electrodes for the Determination of Lead and Cadmium in Seawater by Anodic Stripping Voltammetry

Carbon, gold and silver microwires are revisited under vibrated conditions for detection of trace lead and cadmium in seawater. The Pb and Cd peaks fully overlapped on the bare gold and carbon electrodes and partially on the silver electrode. The sensitivity of all three was insufficient for detection in uncontaminated waters. Peak separation was obtained after coating with mercury (Hg). Only the Hg‐coated silver electrode is suitable when preplated. Limits of detection for Pb using the Hg/C and Hg/Ag electrodes (20–40 pM), and Cd (70 pM), are sufficiently low for Pb and Cd detection in seawater.     

Carbon Nanotubes/Ionophore Modified Electrode for Anodic Stripping Determination of Lead

Bifunctional combination of carbon nanotubes and ionophore is introduced for anodic stripping analysis of lead (Pb²⁺). Carbon nanotubes are employed to improve the detection sensitivity due to their excellent electrical conductivity and strong adsorption ability. An ionophore is utilized for its excellent selectivity toward Pb²⁺. The proposed carbon nanotubes/ionophore modified electrode shows improved sensitivity and selectivity for Pb²⁺. Low detection limit (1 nM), wide linear range (5 nM–8 µM) and excellent selectivity over other metal ions (Cd²⁺, Cu²⁺, and Hg²⁺) was obtained. The practical application has been carried out for determination of Pb²⁺ in real water samples.     

Fabrication of Nano Flower‐shaped Platinum on Glassy Carbon Electrode as a Sensitive Sensor for Lead Electrochemical Analysis

Platinum nanoflowers modified glassy carbon electrodes (PtNFs/GCE) was fabricated simply for lead determination in water samples. The modified electrodes were prepared by electrodeposition in hexachloroplatinic acid solution at constant potential. The influence of deposition time and potential on surface morphology, chemical composition, electrochemical properties of electrode were investigated. At ?0.2 V of potential and 150 s of deposition duration, platinum developed as nanoflower shape and scattered densely all over the glassy carbon surface, producing the largest electrochemically active surface areas. The highest differential pulse stripping voltammetry (DPSV) signal of lead was obtained by using the prepared electrode. Under optimized experimental condition of electrolyte, accumulation potential and time, the peak current was found to be linear proportion to lead concentration in range of 1 to 100 μg L^?1 (slope=0.371) with a limit of detection of 0.398 μg L^?1. The method has good repeatability and reproducibility with relative standard deviations of 1.47 % and 4.83 %, respectively. The modified PtNFs/GCE also demonstrated an excellent long‐term stability with only 9 % decrease in Pb peak current over 30 days. Moreover, the performance of the modified PtNFs/GCE in determination of Pb(II) in two industrial wastewaters was good agreement with data obtained by a graphite furnace atomic absorption spectrometry (GFAAS) method.     

Detection of Trace Zinc by an Electrochemical Microsensor based on Carbon Nanotube Threads

Carbon nanotubes (CNTs) have attracted intense interest due to their excellent properties, such as increased electrode surface area, fast electron transfer rate, significant mechanical strength and good chemical stability. CNT threads, spun from shorter CNTs, inherit the advantages of CNTs, while avoiding the potential toxicity caused by individual CNTs. In this work, microelectrodes based on CNT threads were used to detect trace zinc by anodic stripping voltammetry with an estimated detection limit of 1.4 nM without mercury or bismuth films. CNT threads showed promise for measuring trace metals in small sample volumes without stirring such as encountered in some in vivo and in vitro applications.     

碳糊电极吸附伏安法测定痕量钒

研究了钒 荧光镓(LMG)络合物在碳糊电极上的吸附伏安行为,发现其在+0.81V(vs.SCE)的阳极二次导数峰电流与钒(V)的浓度在一定范围内呈线性关系。在pH=4.3的0.26mol/L的HAc NH4Ac缓冲溶液中,于+0.4V富集,从+0.4至+1.4V以300mV/s线性扫描,方法线性范围为4.0×10-9～1.0×10-7mol/L(5.0×10-7mol/LLMG)和1.0×10-7～1.2×10-6mol/L(2.0×10-6mol/LLMG),检出限为1.0×10-9mol/L(S/N=3)。该法用于煤飞灰,粉煤灰和水样中钒的测定,结果满意。     

Determination of Mercury by Anodic Stripping Voltammetry with a Gold Nanoparticle‐Modified Glassy Carbon Electrode

The aim of this work is the development of a procedure for the determination of aqueous Hg(II) by anodic stripping voltammetry at a gold nanoparticle‐modified glassy carbon electrode (AuNPs‐GCE). The signal of aqueous Hg(II) was measured in the square wave mode; the effect of potential scan parameters, deposition potential and deposition time on the analytical signal was examined. The supporting electrolyte was 0.06 M HCl. The repeatability, the linearity, the accuracy, the detection limit of the procedure and the interferences of other cations and of anions were evaluated. The performance of the AuNPs‐GCE was compared with those of a solid (SGE) and a film (FGE) gold electrode: the AuNPs‐GCE showed to provide lower detection limits and higher repeatability. The renewable surface permits to eliminate memory effects, to maintain a stable baseline and response, and to avoid frequent mechanical cleaning steps. The applicability of the AuNPs‐GCE for Hg(II) determination in drinking waters, sediments and pharmaceuticals was demonstrated.     

Indirect Determination of Trace Copper(II) by Adsorptive Stripping Voltammetry with Zincon at a Carbon Paste Electrode

Traces of copper(II) can be determined by adsorptive stripping voltammetry using 2‐carboxy‐2′‐hydroxy‐5′‐sulfoformazyl benzene (Zincon) as complex forming reagent. First in phosphate buffer pH 6.4, copper(II)‐Zincon complex was adsorbed on carbon paste electrode (CPE) with an accumulation potential of 0.6 V. Following this, adsorbed complex was oxidized and detected by differential pulse voltammetric (DPV) scan from 0.6 to 1.0 V. The effective parameters in sensor response were examined. The detection limit (DL) of copper(II) was 1.1 μg/L and relative standard deviations (RSDs) for 10 and 200 μg/L Cu(II) were 1.81 and 1.03%, respectively. The calibration curve was linear for 2–220 μg/L copper(II). The resulting CPE does not use mercury and therefore, has a positive environmental benefit. The method, which is reasonably sensitive and selective, has been successfully applied to the determination of trace amount of copper in water and human hair samples.     

Simultaneous determination of copper and lead in ethanol fuel by anodic stripping voltammetry

The presence of trace metals in car fuels plays an important role in the engine maintenance. In addition, these metals contribute for the environmental contamination in big cities and their control is necessary. Square Wave Stripping Voltammetry (SWSV) is a very sensitive technique for elemental trace determination and was applied for ethanol fuel analysis. The first studies were done searching for the best conditions for copper determination in alcoholic medium, utilizing gold electrodes. During these studies, the possibility of the simultaneous determination of copper and lead in the same experiment was observed. Two procedures for the analysis of these metals were adopted: The direct quantification of metals in alcohol–water mixtures and a second way that involves the evaporation of the organic solvent and re-suspension of the ions with water+electrolyte. Good recovery values were obtained for synthetic samples spiked with known amounts of metals. The results obtained for the two methods were in good agreement. The detection limits for copper and lead in 75% ethanol–water ratio solution were calculated as 120 and 235 ng l⁻¹, respectively, for 15-min deposition time.     

α-苯偶酰二肟修饰碳糊电极的制备及对合成水样中铜的测定

报道了α苯偶酰二肟修饰碳糊电极的制备及对合成水样中铜的测定，在ｐＨ４．１ 的ＢＲ缓冲溶液中通过在－ １２０Ｖ 电位下富集Ｃｕ２＋后，在－ ０２～＋ ０２Ｖ 电位范围内作阳极溶出伏安法测定。在＋ ００４８Ｖ处有一灵敏的氧化峰，峰电流与Ｃｕ２＋ 浓度在１×１０－ ７～１×１０－ ４ｍ ｏｌ／Ｌ范围内成良好的线性关系，检出限为５×１０－ ８ｍ ｏｌ／Ｌ。     

PVC膜修饰粉末微电极溶出伏安法测定水中铅(Ⅱ)

介绍一种ＰＶＣ膜修饰粉末微电有的溶出伏地。该法不需镀汞,不需搅拌,且可在浓度很稀的支持电南中富集。在浓度为０．０２ｍｏｌ／ＬＨＡｃ介质中,进行阳极溶出伏安扫描,有一灵敏Ｐｂ氧化出现,峰电位为－０．４５３Ｖ,溶出峰电流Ｐｂ＾２＋的质量浓度在５．０×１０＾８￣５．０×１０＾－６ｇ／ｍＬ,范围内有很好的线性关系,检出限为２．０×１０＾－８ｇ／ｍＬ。该法应用于逢来水和湖水中微量Ｐｂ＾２＋的直接测定,测定结     

Determination of Trace Thiocyanate by a Chitosan-Modified Glassy Carbon Electrode

IntroductionMany methods for the determination ofthiocyanate,such as spectrophotometry[1— 6] ,ion-selective electrodes[7— 10 ] ,chromatography[11,12 ] ,flow- injection analysis[13 ] ,voltammetry[14 ] ,fluorimetry[15] ,amperometry[16] ,potentiometricprecipitation titration[17] have been reported. Sincethe methods have been used for the determinationof thiocyanate in waste water,biological samples,food and chemical reagents,the determination ofthiocyanate is of great significance. But theexist…     

Anodic Stripping Voltammetric Determination of Lead in Tap Water at an Ordered Mesoporous Carbon/Nafion Composite film Electrode

A sensitive mercury‐free lead (Pb²⁺) sensor has been proposed based on an ordered mesoporous carbon and Nafion composite film (OMC/Nafion) coated glassy carbon electrode. The analysis of Pb²⁺ using anodic stripping voltammetry (ASV) includes two steps. Pb²⁺ ions are firstly reduced and deposited on the electrode surface in a Pb²⁺ solution (10 mL) during a preconcentration step biased at ?1.0 V, followed by a measurement step by differential pulse voltammetry (DPV) within the potential range of ?0.8 to ?0.3 V (scan rate: 20 mV/s, frequency: 20 Hz, amplitude: 50 mV, pulse width: 50 ms). Linear calibration curve was found to be from 20 nM to 2 μM for Pb²⁺ with a sensitivity of 17.4±1.38 μA/μM after a 5‐min of preconcentration. The detection limit was estimated to be around 4.60±0.12 nM at the signal to noise ratio of 3. Reproducibility (RSD%) was found to be 3.0% for a single sensor with eight measurements and 4.3% for five sensors prepared with identical procedures. The practical application of the proposed lead sensor was verified by determination of trace level of Pb²⁺ in tap water sample.     

Determination of Trace Amount of Lead(II) in Sweet Fruit‐Flavored Powder Drinks by Differential Pulse Adsorptive Stripping Voltammetry at Carbon Paste Electrode

A new method is described for the determination of lead based on the cathodic adsorptive stripping of the lead–nuclear fast red (NFR) at a carbon paste electrode (CPE). The differential pulse voltammograms of the adsorbed complex of lead–NFR are recorded from ?0.10 to ?0.60 V (versus Ag/AgCl electrode). Optimal conditions were found to be an electrode containing 25% paraffin oil and 75% high purity graphite powder, 4.0×10^?5 mol L^?1 NFR; buffer solution (pH of 3.0), accumulation potential and time, ?0.20 V, 60 and 120 s (for high and low concentration of lead), respectively. The results show that the complex can be adsorbed on the surface of the CPE, yielding one peak at ?0.34 V, corresponding to reduction of NFR in the complex at the electrode. The detection limit was found to be 0.2 ng mL^?1 with a 120s accumulation time. The linear ranges are from 0.5 to 50 (t_acc=120 s) and 50 to 200 ng mL^?1 (t_acc=60 s). Application of the procedure to the determination of lead in lake water, bottled mineral water, synthetic samples and sweet fruit‐flavored powder drinks samples gave good results.     

Simultaneous Determination of Cadmium,Lead, Copper,and Thallium in Highly Saline Samples by Anodic Stripping Voltammetry (ASV) Using Mercury‐Film and Bismuth‐Film Electrodes

This paper describes a comparative study of the simultaneous determination of Cd(II), Pb(II), Tl(I), and Cu(II) in highly saline samples (seawater, hydrothermal fluids, and dialysis concentrates) by ASV using the mercury‐film electrode (MFE) and the bismuth‐film electrode (BiFE) as working electrodes. The features of MFE and BiFE as working electrodes for the single‐run ASV determinations are shown and their performances are compared with that of HMDE under similar conditions. It was observed that the stripping peak of Tl(I) was well separated from Cd(II) and Pb(II) peaks in all the studied saline samples when MFE was used. Because of the severe overlapping of Bi(III) and Cu(II) stripping peaks in the ASV using BiFE, as well as the overlapping of Pb(II) and Tl(I) stripping peaks in the ASV using HMDE, the simultaneous determination of these metals was not possible in highly saline medium using these both working electrodes. The detection limits calculated for the metals using MFE and BiFE (deposition time of 60 s) were between 0.043 and 0.070 μg L^?1 for Cd(II), between 0.060 and 0.10 μg L^?1 for Pb(II) and between 0.70 and 8.12 μg L^?1 for Tl(I) in the saline samples studied. The detection limits calculated for Cu(II) using the MFE were 0.15 and 0.50 μg L^?1 in seawater/hydrothermal fluid and dialysis concentrate samples, respectively. The methods were applied to the simultaneous determination of Cd(II), Pb(II), Tl(I), and Cu(II) in samples of seawater, hydrothermal fluids and dialysis concentrates.     

碳糊电极阳极溶出法测定单宁酸的研究

用碳糊电极阳极溶出法研究了单宁酸的测定方法。实验表明,在1.0 mol/LHCl介质中,富集120 s,单宁酸在0.65 V(vs.SCE)处出现阳极溶出峰,在5.0×10-7~6.0×10-5mol/L范围内,其峰电流的大小与单宁酸的浓度呈线性关系,相关系数为0.9991,检出限为1.0×10-7mol/L。该法灵敏度较高,操作简便,可用于啤酒中单宁酸的测定,平均回收率为99.8%。     

微分电位溶出法连续测定饮料中的铜铅镉锌

建立了微分电位溶出法连续测定饮料中痕量铜、铅、镉、锌的新方法。在HAc- Na Ac( p H4 .5)～ 3.5× 1 0 -2 mol·L-1KCl～ 2 .6× 1 0 -5 mol· L-1Hg2 +介质中测定锌 ,然后调节底液为 0 .0 1 mol·L-1HCl,连续测定铜、铅、镉。铜、铅、镉、锌 ,检出限分别为 4 ,0 .1 ,2 ,4 μg· L-1,线性测定范围 Zn2 +:0～ 30 0 μg·L-1,Cu2 +、Pb2 +、Cd2 +:0～ 2 2 0μg· L-1,回收率为 83.4 %～ 1 0 3.3% ,RSD<3.4 % ( n=7)。该法较好解决了金属互化物的影响 ,样品不需消化便可直接测定。