Polarography anodic stripping

A method for the determination of organotin compounds by anodic stripping polarography has been published [121]. It has yet to be applied to seawater. Since the sensitivity permits the measurement of 0.01 ppm of the tin compounds, it is likely to be not quite sensitive enough for seawater and would require a preconcentration step. 

Stripping is the most sensitive form of voltammetry. In anodic stripping polarography, analyte is concentrated into a single drop of mercury by reduction at a fixed voltage for a fixed time. The potential is then made more positive, and current is measured as analyte is reoxidized. In cyclic voltammetry, a triangular waveform is applied, and cathodic and anodic processes are observed in succession. Microelectrodes fit into small places and their low current allows them to be used in resistive, nonaqueous media. Their low capacitance... 

Mead, A.P., A. Parker and E. A. Terry Anodic Stripping Polarography... 

Nikelly, J. G and W. D. Cooke Anodic Stripping Polarography. Anal. 

ASP, anodic stripping polarography CRP, cathode-ray polarography DME, dropping mercury electrode CSP, cathodic stripping polarography Amp., amperometric end point. 

Sinko, I., and Comiscek, S., Determination of lead, cadmiiun, copper, thallinm, bismuth, and zinc in serum by anodic stripping polarography. Mikrochim. Acta pp. 163-172 (1972). 

DP differential pulse, SW square wave, AdCSP adsorptive cathodic stripping polarography, CSP cathodic stripping polarography, ASP anodic stripping polarography... 

When either pulse polarography or anodic stripping voltammetry can be used, the selection is often based on the analyte s expected concentration and the desired... 

From the nature of the process described above it has been referred to as stripping polarography , but the term anodic stripping voltammetry is preferred. It is also possible to reverse the polarity of the two electrodes of the cell, thus leading to the technique of cathodic stripping voltammetry. 

Electrochemistry voltammetry, anodic stripping (ASV), cathodic stripping (CSV), polarography, differential pulse polarography (DPP), ion selective electrode (ISE)... 

Stolzberg [143] has reviewed the potential inaccuracies of anodic stripping voltammetry and differential pulse polarography in determining trace metal speciation, and thereby bio-availability and transport properties of trace metals in natural waters. In particular it is stressed that nonuniform distribution of metal-ligand species within the polarographic cell represents another limitation inherent in electrochemical measurement of speciation. Examples relate to the differential pulse polarographic behaviour of cadmium complexes of NTA and EDTA in seawater. 

Bond et al. [24] examined interferences in the stripping voltammetric method determination of trimethyl lead in seawater using polarography and mercury 199 and lead 207 NMF. It was shown that Hgn reacts with ((CH3) Pb)+ in seawater. Consequently, anodic stripping voltammetric methods for determining ((CH3)3Pb)2+ and inorganic Pb11 maybe unreliable. 

Bilinski, H., Huston, R. and Stumm, W., 1976. Determination of the stability constants of some hydroxo and carbonate complexes of Pb(II), Cu(II), Cd(ll) and Zn(II) in dilute solutions by anodic stripping voltammetry and differential pulse polarography. Anal. Chim. Acta, 84 157-164. 

Electrochemical methods for arsenic determination were initially based on polarography with a dropping mercury electrode. More recent methods, based on anodic stripping voltammetry (ASV), anodic stripping chronopotentiometry (SC), and CSV, rely almost exclusively on the detection of As(III), since As(V) is detected with difficulty because of its perceived electro-inactivity. 

Twenty years ago the main applications of electrochemistry were trace-metal analysis (polarography and anodic stripping voltammetry) and selective-ion assay (pH, pNa, pK via potentiometry). A secondary focus was the use of voltammetry to characterize transition-metal coordination complexes (metal-ligand stoichiometry, stability constants, and oxidation-reduction thermodynamics). With the commercial development of (1) low-cost, reliable poten-tiostats (2) pure, inert glassy-carbon electrodes and (3) ultrapure, dry aptotic solvents, molecular characterization via electrochemical methodologies has become accessible to nonspecialists (analogous to carbon-13 NMR and GC/MS). 

Various spectroscopic techniques such as flame photometry, emission spectroscopy, atomic absorption spectrometry, spectrophotometry, flu-orimetry, X-ray fluorescence spectrometry, neutron activation analysis and isotope dilution mass spectrometry have been used for marine analysis of elemental and inorganic components [2]. Polarography, anodic stripping voltammetry and other electrochemical techniques are also useful for the determination of Cd, Cu, Mn, Pb, Zn, etc. in seawater. Electrochemical techniques sometimes provide information on the chemical species in solution. 

Anodic stripping voltammetry (ASV) can be very usefiil in studies of metal complexation in natural aquatic systems. The technique can be used, under favorable conditions, to determine metal concentrations as low as 10 molL. Further, and again under appropriate conditions, stabihty constants may be determined in a manner analogous to that used in polarography. The principle of the technique involves deposition of a metal ion in reduced form on a static mercury electrode followed by reoxidation through reversal of the polarity. The reoxidation current is related to the metal concentration in the analyte. In the presence of a... 

Anodic stripping voltammetry has been used to determine total arsenic spedes . Pulse polarographic methods have been applied to aqueous and non-aqueous solutions of methyl- and dimethylarsenic adds at concentration levels down to 0.1 /rg/ml . These arsenicals are electroactive in aqueous buffers and in non-aqueous media in which the acidic supporting electrolyte, guanidinium porchlorate, is employed. A direct method of analysis, based on differential pulse polarography, is reported. Detection limits of roughly 0.1/xg/ml (for MMAA) and 0.3p[Pg.190]

The determination of inorganic arsenic by differential pulse polarography and differential pulse anodic stripping voltammetry has been reportedThe polarographic reduction of dimethylarsinic acid and methylarsonic acid has also been reportedBess and CO workers studied the differential pulse polarography of a series of alkylarsonic... 

Part IV is devoted to electrochemical methods. After an introduction to electrochemistry in Chapter 18, Chapter 19 describes the many uses of electrode potentials. Oxidation/reduction titrations are the subject of Chapter 20, while Chapter 21 presents the use of potentiometric methods to obtain concentrations of molecular and ionic species. Chapter 22 considers the bulk electrolytic methods of electrogravimetry and coulometry, while Chapter 23 discusses voltammetric methods including linear sweep and cyclic voltammetry, anodic stripping voltammetry, and polarography. 

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