Here, we present details about the voltammetric behavior of spermine spm , showing a well-defined current peak at View 1 excerpt, cites methods. Electrochemical study of the fungicide acibenzolar-s-methyl and its voltammetric determination in environmental samples.
Journal of environmental science and health. B, Pesticides, food contaminants, and agricultural wastes. View 2 excerpts, cites methods. The polarographic reduction of curcumin has been done in various conditions, at different temperatures, at different solvent and at different concentrations by D.
The electrode … Expand. Determination of Sudan I in drinks containing Sunset yellow by adsorptive stripping voltammetry. Food chemistry. View 1 excerpt, cites background. Ex situ prepared nafion-coated antimony film electrode for adsorptive stripping voltammetry of model metal ions in the presence of pyrogallol red. Admittance or impedance data displayed as milliseconds in contrast with the drop time t1 in DC complex plane plots are often used.
Electroactive species adsorption is sensitively indicated by this method, which thus determines whether redox Differential pulse polarography DPP Figure 4 differs system properties are obscured by a specific type of interaction with the electrode. Strongly absorbable electroinactive compounds yield peaks on the AC curves located at potentials of the adsorption-desorption process.
However, they are much narrower and their frequency dependence differs markedly from the Faradaic peaks. Such peaks were also used for determination of surface active compounds. In general, AC polarography is not very sensitive, in particular in irreversible processes without adsorption.
Pulse techniques improve detection limits since they benefit from the different variation of diffusion and capacitive current intensities with time: when carrying out measurements at the pulse end, the capacitive current is practicably negligible, being the value of the Faradaic current still significant see equation 3.
Variation of the mercury drop area and voltage with time using the static Figure 3. The pulse amplitude is about 20 times smaller than those in the reversible case. New York: Marcel Dekker. Palma de Mallorca. Berlin: Springer Verlag. In: Zyka J ed. New York: Ellis Horwood. II, Electrochemical 2 Methods 2 edn , chap. New York: John Wiley. In SWP, the polarization potential is a linear varying voltage ramp over which a small amplitude square-wave V.
University of the Balearic islands. Spain superimposed. All subsequent polarographic NPP mV 10 — -6 techniques, in which the obtained response is in the Polarograms with peak shape form of a peak derivative polarography, square-wave Differential 50 mV polarography, AC polarography, differential Derivative 50 mV polarography, differential pulse polarography, etc.
AC 50 mV 10 — -6 present a higher resolution, being a difference of only SWP 50 mV — about 50 mV sufficient to be able to discriminate two DPP 50 mV — substances presenting close half-wave potentials. Several polarographic techniques obtained by means of a digital polarograph. The DC technique has been obtained with a dynamic mercury electrode, whereas those of DC tast and AC have been attained with a static electrode and current integration.
The scannings are cathodic, i. This is due definite phase in relation to the applied AC perturbation to the fact that for a constant mass flow rate of mercury, voltage.
Measurement of only total alternating current offers the variation rate of the drop surface is very fast, which is no particular advantage during a detailed electrochemical comparable to a condenser whose plates are changing investigation. Alternating current polarography became their surface very rapidly and, therefore, the charging increasingly attractive after introduction of more current will be initially very high. Tast polarography can active substances may be examined by this method which be considered as an evolution of rapid polarography, in replaces cumbersome balancing bridge measurements.
The cell impedance in the applications. This AC life, a voltage pulse is applied, the amplitude of technique also determines double-layer capacity in the which gradually increases from drop the drop. The pulse presence of a quasi-reversible electrode reaction by duration is about ms. The parameter k0. Admittance or impedance data displayed as milliseconds in contrast with the drop time t1 in DC complex plane plots are often used.
Electroactive species adsorption is sensitively indicated by this method, which thus determines whether redox Differential pulse polarography DPP Figure 4 differs system properties are obscured by a specific type of interaction with the electrode.
Strongly absorbable electroinactive compounds yield peaks on the AC curves located at potentials of the adsorption-desorption process. However, they are much narrower and their frequency dependence differs markedly from the Faradaic peaks.
Such peaks were also used for determination of surface active compounds.
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