Differential cathodic stripping voltammetry

Certain trace substances such as selenium (IV) can be determined by differential cathodic stripping voltammetry (DPCSV). For selenium a rather positive preconcentration potential of-0.2 V is adjusted. Selenium (IV) is reduced to Se2", and Hg from the electrode is oxidised to Hg2+ at this potential. It forms, with Se2" on the electrode, a layer of insoluble HgSe, and in this manner the preconcentration is achieved. Subsequently the potential is altered in the cathodic direction in the differential pulse mode. The resulting mercury (II) peak produced by the Hg11 reduction is proportional to the bulk concentration of SeIV in the analyte. 

Differential cathodic stripping voltammetry Differential electrolytic potentiometry (DEP)... 

DPCSV Differential pulse cathodic stripping voltammetry... 

Ag(I). Ions in bold type are those that can also be determined using differential pulse anodic or cathodic stripping voltammetry. 

Measurement techniques that can be employed for the determination of trace metals include atomic absorption spectrometry, anodic stripping voltammetry, differential pulse cathodic stripping voltammetry, inductively coupled plasma atomic emission spectrometry, liquid chromatography of the metal chelates with ultraviolet-visible absorption and, more recently, inductively coupled plasma mass spectrometry. 

Donat and Bruland [217] determined low levels of nickel and cobalt in seawater by a voltammetric technique, and the nioxime complexes of the two elements were concentrated on a hanging mercury drop electrode. The current resulting from the reduction of Co (II) and Ni (II) was measured by differential pulse cathodic stripping voltammetry. Detection limits are 6 pM (cobalt) and 0.45 nM (nickel). 

Cyclohexane-1,2-dione dioxime (nioxime) complexes of cobalt (II) and nickel (II) were concentrated from 10 ml seawater samples onto a hanging mercury drop electrode by controlled adsorption. Cobalt (II) and nickel (II) reduction currents were measured by differential pulse cathodic stripping voltammetry. Detection limits for cobalt and nickel were 6 pM and 0.45 mM, respectively. The results of detailed studies for optimising the analytical parameters, namely nioxime and buffer concentrations, pH, and adsorption potential are discussed. 

Donat and Bruland [804] studied the speciation of copper and nickel in seawater by competitive ligand equilibration-cathodic stripping voltammetry, differential pulse ASV, and graphite furnace AAS. 

Huynk et al. [218] also used differential pulse cathodic stripping voltammetry for the determination of cobalt and nickel in seawater by dimetbylgly-oxime complexation. They report detection hmits of 0.002 pg/1 for cobalt and 0.005 xg/l for nickel. 

Other forms of voltammetry are as follows (1) fast-scan cyclic voltammetry useful in neuroelectrochemistry (2) nanosecond voltammetry for a 5-pm disk working microelectrode with RC < 1 gs, scan rates of 2.5 MV/s allow for fast kinetics measurements (3) differential-pulse voltammetry with staircase pulses, potential resolutions of 0.04 V and detection limits of 10 8M can be attained (4) anodic (cathodic) stripping voltammetry traces... 

DPCSV = differential pulse cathodic stripping voltammetry DPP = differential pulse polarography AdSV = adsorptive stripping voltammetry DPASV = differential pulse anodic stripping voltammetry. 

Bi-xia, H., Han-Chang, Z., Gui-gang, Pu, Fang, Y., Shen-chun, Z. and Hong, Y. (1985). Differential pulse cathodic stripping voltammetry of whole blood selenium and serum selenium. Anal. Lett. 18, 279. 

Khayamian, T., Ensafi, A.A., Benvidi, A. Extending the dynamic range of copper determination in differential pulse adsorption cathodic stripping voltammetry using wavelet neural network. Talanta 69, 1176-1181 (2006)... 

Adenine and guanine can be analyzed at a carbon electrode and adenine and cytosine at a mercury electrode by differential pulse voltammetry (po-larography) (DPV, DPP) at micromolar concentrations. Determination of bases by cathodic stripping voltammetry (CSV) (see above) gives substantially better sensitivities. In addition to the nucleic acid... 

Manivannan et al. used diamond electrodes to detect Pb(II) in water samples (pH = 1) by differential pulse voltammetry, measuring concentrations down to 4 nM (0.8 ppb) [57]. The preconcentration step was rather long at -1.0 V vs. SCE for 15 minutes. Prado et al. reported on the detection of Pb(II) and Cu(II) at diamond electrodes using anodic stripping voltammetry [156]. The Pb(II) was detected by both anodic- (Pb metal) and cathodic-stripping voltammetry. Pb(II) was detected in a river-water sediment sample (pH = 1) and was quantified using a standard addition method. The metal content in the sediment was found to be - 200 mg/kg by both anodic- and cathodic-stripping voltammetry. The electrode response was improved after microwave activation (e.g., thermal treatment), with a limit of detection of 21 ppb for a 20-second preconcentration time. 

This system is governed via AutoAnalysis software that allows the implementation of a number of polarographic and voltammetric techniques ranging in complexity from amperometry with three electrodes to anodic or cathodic differential pulse stripping voltammetry. 

J.S. Roitz and K.W. Bruland. Determination of dissolved manganese(ll) in coastal and estuarine waters by differential pulse cathodic stripping voltammetry. Analytica Chimica Acta 344 175-183, 1997. 

Panigati, M., Falciola, L., Mussini, P. et al. (2007) Determination of selenium in Italian rices by differential pulse cathodic stripping voltammetry. Food Chem., 105, 1091-1098. 

Dopamine might be a pharmaceutical for which the highest number of MIP based sensors have been constructed. Voltammetry [361,413] and its derivative techniques like differential pulse voltammetry [347,395,418], differential pulse anodic and cathodic stripping voltammetries [353,387,415] ion selective electrodes [372], as swell as piezoelectric microgravimetry [401] and thermogravimetry [427] are among the mechanisms used for the detection in dopamine selective MIP based sensors. 

Sadana, R.S. (1983). Determination of arsenic in the presence of copper by differential pulse cathodic stripping voltammetry at a hanging mercury drop electrode. Analytical Chemistry. Vol. 55, p>p. 304-307... 

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