间断多次扫描电位溶出分析方法的研究

间断多次扫描电位溶出分析是在多次扫描电位溶出分析和间断扫描伏安法的基础上提出的一种新的电位溶出分析技术,它不仅具有多次扫描电位溶出分析灵敏度高的优点,又克服了多次扫描电位溶出分析对多元素分析时元素之间相互干扰的缺点。文章讨论了间断多次扫描电位溶出分析的实验条件,同时用这种方法分析了人尿中镉、铅的含量。间断多次扫描电位溶出分析在电积10分钟时,最低可检测到0.005ng/mL的镉和0.01ng/mL的铅。镉、铅浓度为4ng/mL时,相对标准偏差分别为2.9%和3.2%,证明间断多次扫描电位溶出分析可以同脉冲阳极溶出伏安法媲美。     

Anodic stripping voltammetry and chronopotentiometry of copper at a rotating carbosital disk electrode

The use of a new carbon material — carbosital — for electrodes is reviewed. The behaviour of copper deposited on the carbosital electrode surface in anodic stripping voltammetry and chronopotentiometry is discussed. In anodic stripping voltammetry with a rotating carbosital disk electrode, the peak current and the number of coulombs involved in stripping copper are directly proportional to the square root of the electrode rotation rate during preelectroiysis; the peak current is directly proportional to the potential scan rate during stripping. For anodic stripping voltammetry and anodic stripping chronopotentiometry, linear calibration graphs are obtained in the range 1 X 10^-3–1 x 10^-6 M copper(II). The method is applicable to analysis of high-purity cadmium for copper.     

Stripping chronocoulometry for the determination of pertechnetate

Stripping chronocoulometry is proposed as an alternative to linear-sweep anodic stripping voltammetry when the latter technique gives multiple stripping waves. Such complicated stripping waves are commonly observed at solid electrodes. The determination of pertechnetate (⁹⁹Tc) demonstrates the advantages of stripping chronocoulometry at a wax-impregnated graphite electrode.     

Square-wave anodic stripping voltammetry with a mercury-plated reticulated vitreous carbon electrode

A rotating mercury-plated reticulated vitreous carbon (RVC) electrode is tested for square-wave anodic stripping voltammetry; RVC provides very large surface areas which are easily plated with mercury. Despite the ill-defined geometry of the electrode, the square-wave stripping peaks are very well defined; their behaviour conforms partly to known theory for square-wave stripping from mercury film electrodes. Fast analytical determinations of lead and cadmium in the μg l^?1 range are facilitated by the high efficiency of the preconcentration step and the high sensitivity given by the stripping waveform.     

Simultaneous determination of cadmium and lead in urine by means of computerized potentiometric stripping analysis

In computerized potentiometric stripping analysis for cadmium and lead in urine the samples are acidified with hydrochloric acid to a total concentration equal to 0.5 M. The sample is pre-electrolyzed at —1.25 V vs. SCE for 2 min without prior sample heating or deoxygenation, the working electrode being a mercury pre-coated glassy-carbon electrode. The lead and cadmium concentrations are evaluated by means of standard addition. Detection limits are 1 nM for both elements. Results obtained by potentiometric stripping analysis and by solvent extraction/atomic absorption are compared for samples from unexposed persons and from one patient under penicillamine treatment. The relative merits of the potentiometric stripping, anodic stripping and atomic absorption techniques are discussed.     

pH值对人参皂苷溶出影响规律的液质联用研究

采用液质联用(HPLC-ESI-MSn)技术, 对不同pH值(2.4~11.2)条件下人参皂苷的溶出变化规律进行了系统研究, 并提出了不同人参皂苷化合物的特征质谱裂解规律. 实验结果表明, 中性及碱性溶液对人参皂苷的溶出影响不大, 仅仅在溶出总量上有所差别; 而酸性是影响人参皂苷溶出的一个主要因素, 随着水溶液酸性的增强(pH<4), 人参皂苷溶出的种类明显减少, 表明较强酸性条件下人参皂苷的溶出受到了抑制.     

Studies on substituted phenols by differential pulse cathodic stripping voltammetry: 1. Pentachlorophenol

A study of chlorophenols using differential pulse cathodic stripping voltammetry (dpcsv) is reported. Of the wide range of chlorophenols investigated, only pentachlorophenol and 2,3,4,6-tetrachlorophenol yield stripping peaks.For pentachlorophenol in water, two peaks are obtained at stripping potentials of –1.2 V and –1.58 V versus SCE. In methanol, pentachlorophenol shows one peak with a stripping potential at –1.6 V versus SCE.In the case of 2,3,4,6-tetrachlorophenol in water, two peaks are observed at –1.06 V and –1.6 V versus SCE, while in methanol only one peak arises at a stripping potential of –1.6 V. A procedure was developed for the determination of pentachlorophenol in natural waters.     

Determination of trace metals in rain water by differential-pulse stripping voltammetry

Differential-pulse stripping voltammetry is applied to measure zinc, cadmium, lead and copper by anodic stripping and selenium(IV) by cathodic stripping in rain water at pH 2; subsequently, at pH 9,1, manganese is measured by anodic stripping on the same portion, and cobalt and nickel are measured in the adsorptive mode after formation of their dimethylglyoximates. The instrumental parameters are optimized. The linear ranges, mutual interferences and detection limits are studied. Excellent accuracy is demonstrated; the standard deviation is around 15% at 2.5–50 μg l^?1 levels. The method is shown to be applicable for rain water.     

Recent advances in stripping analysis

Summary A review is given of the key developments of stripping voltammetry in recent years. Important advances such as non-electrolytic (adsorptive) preconcentration schemes, modified or ultramicro stripping electrodes, and versatile and rapid flow systems are discussed. Such developments substantially enhance the analytical power of stripping voltammetry, allowing it to retain its place as one of the most useful techniques for trace analysis.     

Determination of sulfur species by cathodic square wave stripping voltammetry; Compounds relevant to natural sulfur mineralization

The feasibility of rapid analysis of a number of environmentally important sulfur compounds by cathodic square wave stripping voltammetry at a mercury electrode has been investigated. For cysteine/cystine a relatively anodic peak was identified, which is ascribed to the stripping of a mercurous species. The dependence of the peak currents on pH was found to be different for cysteine and cystine. Methionine and thioproline gave similar stripping peaks to those for cysteine. It is proposed that they arise from species deposited by oxidative hydrolysis. A complex ion is proposed to cause the stripping peak of thiosulfate and tetrathionate, while polysulfides give both a HgS stripping peak and a non-adsorptive reduction peak. Limits of detection are in the 10(-8)-10(-9)M range.     

A polarographic and voltammetric study of some primary,secondary and tertiary thioamides of pharmaceutical importance

The d.c. polarographic, and cyclic and cathodic stripping voltammetric behaviour of some primary, secondary and tertiary thioamides based on tetrahydroquinoline, is described. Catalytic reduction occurs in all cases; the primary and secondary thioamides undergo anodic oxidation and cathodic stripping, with the formation of mercury(II) sulphide. Tertiary thioamides are not amenable to anodic electrolysis/stripping. Mechanisms for these oxidation and reduction processes are postulated. Differential pulse polarography has a limit of detection of 5 × 10^?7 M. Cathodic stripping voltammetry can be applied with a detection limit of 2 × 10^?8 M.     

微电极电位溶出法研究进展

本文介绍用于电位溶出分析（ＰＳＡ）的固体微电极的种类及制作，综述了该领域研究的理论进展、技术应用及其方法的优越性，引用文献４１篇     

Theoretical and experimental aspects of the response of stripping voltammetry in flow injection systems

The coupling of stripping voltammetry with flow injection systems offers significant advantages over conventional stripping methods. Equations solved for conventional stripping voltammetry, with steady-state deposition current, are not applicable to flow injection systems. Theoretical equations for the peak current under flow injection conditions are derived. As the total charge passed during the deposition step, ∫i dt, is independent of the shape of the sample plug, the stripping peak current is independent of the degree of dispersion. As a result, precise control of the dispersion or deposition period may not be required. The peak current is predicted to be directly proportional to the sample volume. Experimental results are incorporated to support the theoretical conclusions. The effects of experimental variables such as flow rate, length of tubing, deposition period, or sample volume are presented using cadmium ion as test species.     

Stripping-voltammetric signals on carbon electrodes modified with mercury

Conditions for the formation of a stable and reproducible thin-film mercury microdrop cover on electrodes from carbon glass ceramics, carbon glass, and graphite are proposed. The influence of various factors on the parameters of signals from cadmium (II), lead (II), and copper (II) is studied by stripping voltammetry with linear, differential-pulse, sinusoidal, and square-wave potential sweep. The parameters of the stripping voltammetric experiment are optimized. The value of RSD in determining the specified modeling trace components did not exceed 15%. Approaches to the multicomponent stripping voltammetric analysis of waters are proposed.     

Applications of charge stripping/charge exchange spectra of organic ions

The application of a new technique which involves the combination of charge stripping and charge exchange processes has been investigated. Ions are charge-stripped in the second field-free region of a triple-sector mass spectrometer (BEE geometry), and then subjected to a charge exchange reaction in the third field-free region. The resulting charge stripping/charge exchange (CS/CE) spectrum is free from interference, which is otherwise common in charge stripping spectra. Comparisons between charge stripping and CS/CE spectra are made in cases where both kinds of spectra are obtainable. In order to assess the applicability of this new technique to studies of isomeric ion structures, species for which charge stripping spectra have previously been unobtainable have been chosen. CS/CE spectra of [C₆H₆]⁺˙, [C₆H₅]⁺, [C₈H₁₀]⁺˙ and [C₇H₇O]⁺ ions from a variety of precursors are recorded: in most cases, sufficient differences are observed to permit distinction between isomeric structures (or mixtures of structures). Previous studies which have shown that stable doubly charged molecular ions of ethane cannot be formed by the charge stripping technique are confirmed from its CS/CE spectrum.     

Differential pulse anodic stripping voltammetry at the wall-jet electrode

Differential pulse anodic stripping voltammetry at the wall-jet electrode requires careful consideration of flow conditions in the plating and stripping steps as well as the electrochemical parameters such as modulation amplitude and clock period. A systematic appraisal of the various factors affecting the differential pulse stripping current is described. Although the stripping current depends on the stripping solution flow rate, the differential pulse mode is preferred to dc stripping because of its greater sensitivity and the abililty to obviate oxygen interference.     

Determination of tellurium(IV) in perchloric acid by stripping voltammetry with collection

The deposition and stripping of teUurium(IV) at a rotating gold ring—gold disk electrode is described. Tellurium(IV) is reduced to the metal by two cathodic procedures, and three activity states of electrodeposited tellurium are observed. For sub-monolayer depositions, a single stripping peak is observed. Determination of telIurium(IV) by stripping voltametry and by Stripping voltammetry with collection is described. The detection limits are 1 X 10^-5 M and 5 X 10^-11 M, respectively.     

Determination of Gold by Stripping Voltammetry in Platinum Gold Ore Mineral Raw Materials on Grafite Electrode Modified by Bismuth

The paper considers the possibility of determining the gold (III) by stripping voltammetry on graphite electrode modified by bismuth. It is shown the modification of the graphite electrode by bismuth increases the sensitivity of detection of gold in 2 times. The comparison of the results of gold determination by stripping voltammetry and by atomic absorption is presented. The advantages of stripping voltammetry on a graphite electrode modified with bismuth for gold determination are given.     

Extraction of sulphuric acid from technological solution of hydroxylamine sulphate

The extraction of sulphuric acid from solutions containing hydroxylamine sulphate and ammonium sulphate with Cyanex 923 and the acid stripping from loaded Cyanex 923 are studied at 20 and 50°C. The effect of the numbers of extraction and stripping stages and the volume phase ratios in extraction and stripping upon sulphuric acid recovery is discussed. The process can be design to obtain a high or low recovery of sulphuric acid but with its low or high concentration, respectively.     

Review of adsorptive stripping voltammetric methods for cobalt determination in the presence of a zinc matrix

Different polarographic and voltammetric methods for the determination of Co in the presence of a large excess of zinc are reviewed. Adsorptive stripping voltammetry with in-situ matrix exchange and catalytic adsorptive stripping voltammetric methods are recommended for monitoring Co traces in zinc plant electrolyte. The principles of the catalytic adsorptive stripping voltammetric methods for Co determination are presented. The correct selection of the investigated supporting electrolytes, enabling the monitoring of Co traces in a zinc plant electrolyte by means of catalytic adsorptive methods is also discussed. The catalytic adsorptive voltammetric procedures offer the possibility of the determination of Co or Co and Ni traces in metallic zinc and zinc salts.