Polarography, Barker’s square-wave

Reverse pulse methods Application of pulse methods Alternating current and square-wave techniques Principles of alternating current polarography Basic relationships for the AC processes Improved ACP techniques Applications of AC polarography Tensammetry and detection of surface-active substances Square-wave polarography (Barker s method)... 

The method of potentiostatic pulses is sometimes combined with the DME (called pulse polarography). hi this case the pulse frequency should match the drop frequency, where each pulse is used at a definite time in the drop life, hi Barker s method, large pulse amphrndes are used. Other versions of the potentiostatic pulse technique are square-wave and staircase voltammetry here smaU-amphtude pulses are used. 

Originally (in the technique introduced by Barker [89] in 1952) the square-wave potential was applied to the DME with constant modulation frequency (225 Hz) and slow scan rate of the voltage ramp (about 2 mV s" ). The current response was recorded at the end of each drop life in a short period of time ( 2 ms). This method could be treated by the steady-state theory in an analogous way to the derivative and differential pulse polarography. It has attained considerable attention for reversible electrode processes due to its applicability especially in trace analysis [90]. 

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