Inversion voltammetry

N. A. Tananaev, simultaneously with F. Feigl, developed the spot analysis. Known Tserevitinov method for determining labile hydrogen atoms in organic compounds (1902-1907 should be noted (the method was later improved by A.P Terent ev). In the USSR, there were powerful schools in liquid-liquid extraction and inverse voltammetry. 

As a result a new approaehes in DCP-ai e atomie-emission speetrometry were applied for Ca, Mg, Cu, Zn, Fe and P determination in blood semm and Ca, Mg, Cu, Zn, Fe, P, Mn, Pb, Cd, Sn, Sr et al. - in human and animals hair with relative standai d deviation (RSD) about 10-20 %. The aeeuraey eontrol has been realized by a eomparison of data produeed with the results of independent methods (atomie-absorption speetrometry and inverse voltammetry). 

Monien et al. [515] have compared results obtained in the determination of molybdenum in seawater by three methods based on inverse voltammetry, atomic absorption spectrometry, and X-ray fluorescence spectroscopy. Only the inverse voltammetric method can be applied without prior concentration of molybdenum in the sample, and a sample volume of only 10 ml is adequate. Results of determinations by all three methods on water samples from the Baltic Sea are reported, indicating their relative advantages with respect to reliability. 

As the main aim of trace analysis is usually determination of the mass (expressed as the number of moles) of a given component in a studied sample, molar concentration is generally not used. Some exceptions are electrochemical methods, where the analytical signal (e.g., current intensity) is a direct function of molar concentration [9]. Therefore, in voltamperometric techniques the detection limits are usually given in molar concentration units (Table 1.2). Thus, for nickel (molar mass M = 58.7 g/mol) the detection limit in inverse voltammetry is approximately 6 X 10 mol/L, and is expressed as a mass fraction, 3.5 x 10 g/dm, or as a percentage, 0.35 x 10 %. In spectrophotometry, when concentrations are given in molar units then molar absorptivities are also used. For example, molar absorptivity e = 5xl0 " L/mol cm corresponds (for molar mass M = 58.7 g/mol) to molar absorptivity a = 5 x 10 /(58.7 x 10 )mL/g cm (i.e., 0.85 mL/g cm). 

Neeb, R. Kiehnast, I.Z. Effect of salts on the anodic peak height in inverse voltammetry. Anal. Chem. 1967,241, 142-155. 

Electrochemical methods are preferred for aqueous solutions, such as polarogra-phy, differential pulse polarography, pulse voltammetry, and pulse inverse voltammetry. The anodic (ASV) and cationic (CSV) stripping voltammetry are at present the most sensitive analytical methods for copper determination with a detection limit of 5 ng (Donat et al. 1994). 

Physical methods utilizing neutron activation, atomic emission spectrometry, graphite furnace atomic absorption spectrometry and adsorptive inverse voltammetry are presently used. Neutron activation determination seems to be the most reliable method for the analytical determination of vanadium in biological specimens taken from occupationally nonexposed and exposed people (Allen and Steinnes, 1978 Glyseth et al., 1979). In... 

At present, the most commonly used techniques for the determination of vanadium are graphite furnace atomic absorption spectrometry (GFAAS), inductively coupled plasma emission spectrometry (ICP-AES) and adsorptive inverse voltammetry (Fleischer et al., 1991). 

Determination of thallium by inversion voltammetry Maceration and extraction... 

To determine thallium by inversion voltammetry, pick up the residue from the maceration process in the beaker with 20 ml of 0.05 m EDTA, expose to nitrogen and reduce cathodically on a dropping mercury electrode. The amalgam thus produced is subsequently dissolved anodically. The current-voltage curve is registered with a recording instrument. 

Evaluate the peaks occurring in inversion voltammetry by comparing the peak heights of the measurement signals received. 

Electrochemical methods continue to be important as well, including inverse voltammetry, coulometry. amperometry, and potentiometry (- Analytical Voltammetry and Polarography) indeed, their overall role has actually been expanded with the development of such chemical techniques as ion chromatography and chelate HPLC. 

Various means of trace accumulation and determination are used in stripping voltammetry. In the simplest case the analyte is reduced to the metal and accumulated as an amalgam at a stationary mercury electrode (HMDE or TMFE). The determination step proceeds in the reverse direction to the accumulation and is based on the anodic stripping of the metal (reoxidation). This process of ASV is also known as inverse voltammetry and can be illustrated as follows ... 

About the Terms Inverse Voltammetry Amalgam Polarography with Preconcentration Thin-Film Polarography with Preconcentration, and Stripping Voltammetry ... 

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