叠式循环阶梯脉冲伏安法：Ⅰ.简单可逆电极体系

本文提出循环阶梯脉冲伏安法和对位叠式循环阶梯脉冲伏安法，推导出简单可逆电极体系的电流方程，研究了峰电流与诸因素的关系，并进行了实验验证，发现对位叠式循环阶梯脉冲伏安法有较多的优点     

Staircase voltammetry with finite diffusion space

A theory of the staircase voltammetry in a thin-layer cell is developed. The influence of the cell thickness and the redox reaction rate constant on the current and the peak potentials is analyzed. For moderately thick cells, the kinetic maximum is predicted. The relationship between peak currents and the square root of the scan rate is not linear and the response may entirely vanish if the redox reaction is fast, the cell is very thin and the scan rate is slow.     

超微盘电极上阶梯扫描伏安法可逆波理论

本文报道超微盘电极上阶梯扫描伏安法可逆波理论,对电流-电位曲线的性质进行了讨论.利用K₄Fe(CN)₆·KCl体系进行了验证,实验结果与理论相符.     

The surface catalytic mechanism: a comparative study with square-wave and staircase cyclic voltammetry

A pseudo-first-order catalytic mechanism in which both reactant and product of a redox reaction are strongly immobilized on an electrode surface is theoretically analysed under conditions of square-wave (SWV) and staircase cyclic voltammetry (SCV). A mathematical procedure is developed under diffusionless conditions. The relationships between the properties of the voltammetric response and both the kinetic parameters of the redox reaction and the parameters of the excitation signal are studied. The phenomenon of the quasi-reversible maximum is discussed. A comparative study between SWV and SCV is presented and the limitations and advantages of both techniques, from analytical and kinetic points of view, are discussed. The theoretical predictions are experimentally confirmed by the redox reaction of azobenzene in the presence of hydrogen peroxide as an oxidizing agent. Electronic Publication     

微环电极上阶梯扫描伏安法可逆波理论及验证

本文推导了微环电极上阶梯扫描伏安法可逆波方程式,经验证,结果与理论相符。 1 理论 对于R—ne O的反应,微环电极上计时电流表达式为     

微分脉冲阴极溶出伏安法测定阿米卡星

硫酸阿米卡星(Am ikacin sulfate)是一种氨基糖苷酸类抗生素,化学名为O-3氨基-3-脱氧-а-D-蒲吡喃糖基-(1-6)-O-[6-氨基-6-脱氧-а-D-蒲吡喃糖基-(1-4)]-N-(4-氨基-2-羟基-1-氧丁基)-2-脱氧?D-链霉胺硫酸盐。目前报道的测定方法主要有高效液相法[1]、镍毛细管电泳法[2]。本文研究了阿米卡星在玻碳电极上的电化学行为。微分脉冲溶出伏安法是一种灵敏度很高的痕量分析方法,本文利用该方法对阿米卡星进行了测定,发现阿米卡星在pH=2的盐酸底液中,产生一灵敏的还原峰,可用于定量测定。平行测定了7次,RSD为2·05%,该方法可用于注射液及血清中…     

微分脉冲阴极溶出伏安法测定呋喃唑酮

研究了呋喃唑酮在玻碳电极上的伏安行为。在 1mol LHCl底液中 ,用微分脉冲阴极溶出伏安法得到一灵敏的呋喃唑酮还原峰 ,峰电位为 0 .0 38V(vs.Ag AgCl)。峰电流与呋喃唑酮浓度在 8× 1 0 -6～ 1× 1 0 -4 mol L范围内呈线性关系 (r=0 .9984) ,检出限为 8× 1 0 -8mol L。该法已用于片剂与合成血清样品中呋喃唑酮含量的测定     

胆红素的伏安特性及其微分脉冲伏安法测定

建立中成药中胆红素定量测定的微分脉冲伏安法。在多种介质中研究胆红素在玻碳电极上的电化学行为 ,全面优化条件后 ,采用标准加入法对中成药中胆红素进行测定 ,并通过与药典中标准方法对照和干扰实验及回收率实验对本方法进行评价。在 0 .2mol·L-1HAc NaAc 5 0 %EtOH和 1 1 5mol·L-1KH2 PO4 Na2 HPO4 溶液中 ,峰电流与胆红素浓度分别在 6.2 5× 1 0 -7～ 1 .0 0× 1 0 -5mol·L-1(r=0 .9976)和 5 .0 0× 1 0 -8～ 3.0 0× 1 0 -6mol·L-1(r=0 .9939)范围内呈良好的线性关系 ,检测下限分别为 5 .0× 1 0 -8mol·L-1和 5 .0× 1 0 -9mol·L-1。众生丸和牛黄解毒片中胆红素的质量分数分别为 0 .0 86%和 0 .1 0 9% ,RSD分别为 3 4%和 3.0 % ,回收率为 96.6%～ 1 0 4 .1 % ,其结果与药典中标准方法测定结果基本一致。     

诺必擂停的电化学性质研究及示差脉冲伏安法测定

研究了抗癌药物诺必擂停在玻碳电极上的电化学行为及其反应机理,建立了一种灵敏的测定诺必擂停的分析方法。实验结果表明,在pH 2.0的磷酸盐缓冲溶液中,诺必擂停在-0.905 V电位处产生灵敏的还原峰,该还原峰电流与诺必擂停的浓度在8.21×10^-6-1.09×10^-4mol/L范围内呈现良好的线性关系（r=0.9923）,检出限为5.47×10^-6mol/L。该法已用于人血清中诺必擂停的测定,回收率在94.5%-104.4%之间。     

Determination of bromadiolone in pheasants and foxes by differential pulse voltammetry

Bromadiolone, a commercially used anticoagulant rodenticide, was determined in tissues of various animals by differential pulse voltammetry with a carbon-paste electrode. Under the most suitable experimental conditions (step potential of 25?mV?s^?1 and 0.2?mol?L^?1 acetate buffer, pH 4.2), the limit of detection was 0.5?ng?mL^?1. The electroanalytical method was consequently used to investigate the bromadiolone transport within the food chain. Pheasants were exposed to bromadiolone and then used as feed for a fox. The average levels were 528 and 198?ng of bromadiolone per gram of fresh weight of liver of pheasant and fox, respectively. Due to the surprisingly lower content of bromadiolone in the latter, a basic biochemical analysis, particularly blood coagulation, was performed. Among the parameters studied (thrombin time, prothrombin time, activated partial thromboplastin time, and fibrinogen), there was prolongation of the prothrombin time and activated partial thromboplastin time.     

Electrochemical solid phase micro-extraction and determination of salicylic acid from blood samples by cyclic voltammetry and differential pulse voltammetry

The electrochemical solid phase micro-extraction of salicylic acid (SA) at graphite-epoxy-composed solid electrode surface was studied by cyclic voltammetry. SA was oxidized electrochemically in pH 12.0 aqueous solution at 0.70 V (vs. saturated calomel electrode) for 7 s. The oxidized product shows two surface-controlled reversible redox couples with two proton transferred in the pH range of 1.0∼6.0 and one proton transferred in the pH range of 10.0∼13.0 and is extracted on the electrode surface with a kinetic Boltzman function of i _p = 3.473–4.499/[1 + e^{(t − 7.332)/6.123}] (χ ² = 0.00285 μA). The anodic peak current of the extracted specie in differential pulse voltammograms is proportional to the concentration of SA with regression equation of i _p = −5.913 + 0.4843 c (R = 0.995, SD = 1.6 μA) in the range of 5.00∼200 μM. The detection limit is 5.00 μM with RSD of 1.59% at 60 μM. The method is sensitive and convenient and was applied to the detection of SA in mouse blood samples with satisfactory results.     

Determination of chromium(VI) in dialysis fluids by alternating current and differential pulse voltammetry

Alternating current (ACV) and differential pulse voltammetry (DPV) are employed for the determination of Cr(VI) in dialysis fluids, using 0.1 mol/1 dibasic ammonium citrate as supporting electrolyte (pH 5.9). A three-electrode cell was used: The working electrode was a long-lasting sessile-drop mercury electrode (LLSDME) with a drop time of 240 to 300 s. Precision, expressed as relative standard deviation (s _r%), and accuracy, expressed as relative recovery (R%) are also reported.     

Differential pulse anodic stripping voltammetry detection of metallothionein at bismuth film electrodes

As a representation of metalloproteins, metallothionein (MT), which plays important biological and environmental roles such as in the metabolism and detoxification of some metals, was detected at bismuth film electrode (BiFE) by differential pulse anodic stripping voltammetry (DPASV). In pH 2–5.5, two well-defined anodic peaks were produced and attributed to the Zn²⁺ and Cd²⁺ inherent to MT. The calibration plot of DPASV peak currents for Cd²⁺ inherent to MT versus MT concentrations showed a good linearity with a detection limit of 3.86 × 10⁻⁸ mol/L for MT. As a non-toxic excellent electrode material, BiFE shows good performance for detecting MT, and is expected to find further applications in the studies of many other metalloproteins.     

Determination of arsenic in gold samples using matrix exchange differential pulse stripping voltammetry

A method comprising matrix exchange differential pulse stripping voltammetry (DPSV) at a gold film electrode has been proposed for the determination of small quantities of arsenic in pure gold. A wall-jet cell (WJC) and an on-line deoxygenation system were used to facilitate matrix exchange. The gold(I) cyanide complex was formed to avoid gold deposition on the electrode together with the arsenic. The pH of the sample solutions were adjusted to 3, as alkaline solutions gold(I) cyanide produced interference and the uncomplexed cyanide led to passivation of the gold film electrode. Matrix exchange electrolytes consisting of 4 mol l⁻¹ hydrochloric acid or a combination of 2 mol l⁻¹ sulphuric acid and 0.2 mol l⁻¹ hydrochloric acid could be utilised. Arsenic concentrations as low as 0.1 mg l⁻¹, could readily be detected in a gold matrix with a 60 s deposition time. While, cobalt and silver did not interfere with the arsenic determination, copper interfered even when present at similar concentrations to that of arsenic.     

Determination of nitrobenzene by differential pulse voltammetry and its application in wastewater analysis

A new method for the determination of nitrobenzene (NB) by differential pulse voltammetry (DPV) based on an adsorptive stripping technique was developed. Cyclic voltammetry (CV) was used in a comparative investigation into the electrochemical reduction of NB at a glassy carbon electrode (GCE). With this electrode, the sharp peak of NB appeared at −0.71 V (vs. Ag/AgCl). The experimental parameters were optimized. Studies on the effect of pH on the peak height and peak potential were carried out over the pH range ca. 9.0–11.5 with sodium carbonate/sodium hydrogen carbonate buffer solution. A solution of pH 9.9 was chosen as analytical medium. Cathodic peak currents were found to be linearly related to the concentration of NB over the range ca. 12.3–1.23 × 10⁴ μg L⁻¹ with relative standard deviations of ca. 3.26–6.75%. The detection limit of NB in water was 5.42 μg L⁻¹. The interference of organic and inorganic species on the voltammetric response was also studied. The proposed method was applied to the determination of NB in wastewater samples with an average recovery of ca. 95.9–102.4%.     

Determination of trace amounts of morphine in human plasma by anodic adsorptive stripping differential pulse voltammetry

New adsorptive anodic differential pulse stripping voltammetry method for the direct determination of morphine at trace levels in human plasma of addicts is proposed.The procedure involves an adsorptive accumulation of morphine on a HMDE,followed by oxidation of adsorbed morphine by voltammetry scan using differential pulse modulation.The optimum conditions for the analysis of morphine are pH 10.5,Eacc of -100 mV（vs.Ag/AgCl）,and tacc of 120 s.The peak current is proportional to the concentration of morphine,and a Linear calibration graph is obtained at 0.01-3.10μg mL^-1.A relative standard deviation of 1.06%（n=5）was obtained,and the limit of detection was 3 ng mL^-1.The capabiLity of the method for the analysis of real samples was evaluated by the determination of morphine in spiked human plasma and addicts human plasma with satisfactory results.     

纳米银修饰电极差分脉冲伏安法测定盐酸金霉素

建立了快速测定盐酸金霉素(CTC)的方法。通过NaBH4还原法制备纳米银(AgNPs)溶胶,并利用X射线衍射和紫外-可见光谱进行表征。将制备好的AgNPs滴涂到玻碳电极表面制备修饰电极(AgNPs/GCE),研究了CTC在AgNPs/GCE上的电化学行为及伏安法测定,优化了缓冲溶液和pH等检测条件。结果表明,CTC在pH 3.3的柠檬酸-NaOH-HCl缓冲溶液中检测效果最佳。CTC在AgNPs/GCE上发生2个电子和2个质子的不可逆电化学氧化反应,且反应受吸附控制。最佳条件下,CTC的氧化峰电流与其浓度呈现良好的线性关系,线性范围为0.5~100μmol/L,检出限为0.14μmol/L。该修饰电极可用于河水样品检测。     

Determination of dissolved manganese in natural waters by differential pulse cathodic stripping voltammetry

A procedure based on differential pulse cathodic stripping voltammetry on the graphite electrode is described for the determination of dissolved manganese in natural waters buffered at pH about 6.5 with acetate solution. In order to avoid interference of iron(II) the addition of fluoride is used. The limit of detection is 3 g/l for a deposition time of 6 min. Acidification and UV-irradiation are recommended for samples containing dissolved organic matter. Results of manganese determination in table mineral waters are reported and the possibility of manganese speciation is discussed.     

面粉中增白剂过氧化苯甲酰的示差脉冲伏安法测定

研究了以二氯甲烷作为萃取剂,二氯甲烷-乙酸(1.5×10-2mol/L)为底液,四丁基高氯酸铵(0.01mol/L)为支持电解质,玻碳电极作为工作电极,采用示差脉冲伏安法测定过氧化苯甲酰。过氧化苯甲酰的阴极峰电位为-0.045V(vs.Ag/AgCl),峰电流与过氧化苯甲酰浓度在2.5×10-6～1.0×10-4mol/L范围内呈良好的线性关系,检出限为2.5×10-7mol/L。本法可直接用于小麦面粉中增白剂过氧化苯甲酰的测定。     

电活化玻碳电极差分脉冲溶出伏安法测定磺胺嘧啶

采用线性循环溶出伏安法和差分脉冲溶出伏安法对磺胺嘧啶在电活化玻碳电极上的电化学行为进行了研究。玻碳电极在PBS溶液中(pH 7.0),用恒电位法在1.7 V阳极氧化400 s,在B-R缓冲溶液中,磺胺嘧啶在1.02V(vs.Ag/AgCl)处有一良好的氧化峰,在0.02～0.25 V/s范围内,其氧化峰电流与扫描速率呈良好线性关系,表明电极过程为受吸附控制的不可逆过程。差分脉冲溶出伏安法的氧化峰电流(Ipa)与磺胺嘧啶浓度1×10-6～1×10-4mol/L范围内呈良好的线性关系(r=0.9977),检出限为8.7×10-7mol/L(S/N=3)。方法已用于分析磺胺嘧啶片剂的分析。