Polarography single-sweep

When the product of the electrode process is itself electroactive in the same solution in which its electrolysis is performed its identification is possible with oscillographic polarography, single-sweep oscillography, the periodical change of voltage or the hanging mercury drop electrolysis. 

Vogel, J. Single-sweep Method Progress in Polarography II, 429, ed. 

Single-sweep i-E curves are step-like in shape for kinetic currents whereas, for diffusion currents, they show peaks. Similarly the incisions on the dEjdt = f E) curves recorded in oscillographic polarography are L-shaped for kinetic currents, whereas they are V-shaped for diffusion currents. 

Vogel, J. (1962). Single Sweep Method in Progress in Polarography (P. 

Meprobamate in N KOH and at a concentration of 10 3m produces a peak of Q value 0. °. For analytical purposes this peak was compared to that of a standard . Meprobamate in N NaOH has been observed to give a response to single sweep A.C. oscillographic polarography. 

Z. Xi, et. al.. Determination of vitamin E by single-sweep oscillo-polarography with wax-impregnated graphite electrode, Fenxi Huaxue, 19... 

Z. Gao, et. al.. Determination of trace nitrite by single-sweep polarography, Gcuodeng XueXiao Huaxue Xuebao, 12 (3), 329-31 (1991). 

In an ammonium chloride solution containing 10% dioxane or ethanol, the Sm complex of rhodamine B exhibits a reductive dc polarogram at —1.70 V SCE. The wave height is directly proportional to the concentration of Sm(III) within the range of 2 X 10 to 2 X 10 M. Since there is a large adsorptive wave P2 of rhodamine B, which precedes the complex wave, it is difficult to increase further the sensitivity either in dc or single-sweep polarography. 

Fig. 5.18 Potentiostatic methods (A) single-pulse method, (B), (C) double-pulse methods (B for an electrocrystallization study and C for the study of products of electrolysis during the first pulse), (D) potential-sweep voltammetry, (E) triangular pulse voltammetry, (F) a series of pulses for electrode preparation, (G) cyclic voltammetry (the last pulse is recorded), (H) d.c. polarography (the electrode potential during the drop-time is considered constant this fact is expressed by the step function of time—actually the potential increases continuously), (I) a.c. polarography and (J) pulse polarography...

Polarography, invented in 1922 by Czech electrochemist J. Heyrovsky, was in the period 1930 up to the end of the 1950s the worldwide commonly used electroanalytical method. In its classic form it represents a special case of linear sweep voltammetry characterized by the use of the dropping mercury electrode (DME). The linear voltage scan applied to the electrolytic cell is slow (typically 0.1 V up to 0.4 V min ). With regard to the usual mercury drop-life (1 -4 s) the fundamental assumption can be accepted that each single drop is polarized at nearby constant potential. 

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