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Discrete Fourier Transform Analysis of Chronoamperometric Currents Obtained Under Ultrasound
Author(s) -
E Lihai,
Zhou Ding
Publication year - 2004
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200302786
Subject(s) - ultrasonic sensor , electrode , analytical chemistry (journal) , fourier transform , amplitude , materials science , electrolyte , fourier analysis , ultrasound , intensity (physics) , chronoamperometry , chemistry , electrochemistry , acoustics , cyclic voltammetry , optics , physics , mathematics , chromatography , mathematical analysis
A discrete Fourier transform (DFT) technique was used to analyze chronoamperometric currents at a Pt microdisk electrode (Ø=15 μm) in an electrolyte containing [Fe(CN) 6 ] 3− /[Fe(CN) 6 ] 4− under ultrasound at a frequency of 26.3 kHz and the powers of 0–50 W. The currents were measured by a high‐speed data acquisition card. Considering the effects of acoustic vibrations and cavitations on the limiting currents, a microdisk electrode and a high frequency sampling (10 MHz) were used to collect the current signals to restrain the deviation of average from sampling period in other methods. The results show that the amplitudes at 0 Hz and 26.3 kHz are related to the decay of ultrasound at constant power output when the separation between sono‐horn and electrode increases, and also related to the reactant concentration at the same ultrasonic conditions. The frequency signals are always shown in frequency spectrum despite different ultrasonic conditions. The amplitudes reflect the intensity of ultrasound and the concentration of reactant in solution, so they can be called specific frequencies. This method can be used to analyze quantitatively the effects of ultrasound on electrochemical reaction, determine the reactant concentration and measure the distribution of ultrasonic intensity in a solution.