Method for phase angle measurement in second harmonic alternating current polarography

Abstract

Recent workhas established that second harmonic ac polarographic measurements may be utilized advantageously in the determination of rate parameters of fast electrode processes (1-3). Excellent agreement between experiment and theory has been observed for several examples of the socalled quasi-reversible case (1-3). Similar success has been realized with one system characterized by a fast follow-up chemical reaction (4). Rate parameters obtained in these studies agree favorably with those yielded by more familiar techniques, such as fundamental harmonic ac polarographic measurements (5, 6). The sensitivity of second harmonic ac polarographic currents to kinetic parameter variations led in one case to the suggestion that the charge transfer coefficient may be determined with three significant figure accuracy (1).These and earlier investigations (see references 1-6 for a more complete bibliography) have been confined almost solely to measurement of the second harmonic current amplitude. Only brief reports of semi-quantitative attempts at second harmonic phase angle measurements may be found in the literature (7,8).In conventional (fundamental harmonic) ac polarography,

Direct measurement of Er1/2 with reversible and EC [electrochemical] electrode processes by second harmonic alternating current polarography and voltammetry

“…With total second harmonic current measurements (absolute value), the minimum value of 7(2 ) was used in instances where the current did not exactly attain a zero value, due to instrumental imperfections (e.g., incomplete rejection of the larger fundamental harmonic response and/or failure to take a data sample precisely at the potential of zero current can lead to non-zero minimum currents which amount to 1-2% of the peak current). With phase-sensitive detection, the observed response always crosses zero (18) and the potential where I(2wt) = 0 could be readily and accurately located. Both the in-phase and quadrature second harmonic current components were recorded when phase-sensitive detection was used and, in (36) J. W. Hayes, D. E. Glover, D. E. Smith, and M. W. Overton, Anal.…”

Electrochemical relaxation techniques

“…This system was predicted to be three orders of magnitude more sensitive than conventional ac polarography. Direct recording of phase angles in ac polarography has been reported by Glover and Smith (139). The same circuit allows direct recording of second harmonic complex plane polarograms.…”

“…Inorganic. Hydrogen kinetics on mercury (87, 271), and in the presence of tetraiodomercury (II) formation (86, 88), hydrogen coverage and rate on platinum (170); kinetics and negative admittance of indium (96,97,227,369) and oscillatory behavior (99); rate constant and transfer coefficients of zinc (232,244), in low-activity water (45), in alkali (125), correlation with double layer structure (347), ac polarograms and double layer capacity (324,862); rate constants and transfer coefficients of cadmium (139,152,227,232,239,248,863) and double layer effects (156), in mixed solvents (50), ac polarograms and double layer capacity (65,324,362), dissociation rate of EDTA complex (232); impedance of lead (232) and specific adsorption in chloride (368); correlation of dehydration rate with reduction rates of cobalt(II), manganese (II), and iron (II) (55); anodic dissolution of iron(II) (122); unusual phase angle of iron(II)/chlorite catalytic reaction (102); nonspecific adsorption and effect on impedance of barium reduction (371). oxalate complexes of iron(III)/(II) (222) and phase angle by second harmonic ac polarography (139); precise transfer coefficient measurements of vanadium (III)/(II) (316) bromine/bromide at platinum (80); evidence for specific adsorption of fluoride and bifluoride on mercury (390).…”

Advantage of Fractional Calculus Based Hybrid‐Theoretical‐Computational‐Experimental Approach for Alternating Current Voltammetry

“…The alternating current (ac) voltammetry has the quality to unify the positive outcomes of CV and EIS in wide range of potential of interest. In ac voltammetry, a sinusoidal potential perturbation of a particular ω and small amplitude (DE) is superimposed over E t ð Þ, which linearly varies with t. The research and development on ac polarography/voltammetry started almost fifty years ago by few research groups [1][2][3][4][5]. The research was then extended to explore the utilization of Fourier transformation in ac voltammetry [6][7][8][9][10][11].…”