Method for determining the quantity (E0' + Ej) for a glass-calomel electrode pair in anhydrous acetic acid

Abstract

A more precise method has been developed for evaluating the reference potential (E°' + Ej) for specific glass-calomel electrode pairs in anhydrous acetic acid as the solvent. The computed results are derived from measured potentials for the given electrode pair In MOAc solutions and from assumed values for the ion pair dissociation constants of the bases. The variation in the reference potential is less than ±3 mV upon substituting different glass electrodes having the same specifications from the manufacturer. An Indirectly calculated reference potential based on published data confirmed the order of magnitude of the experimental values.

Characterization of the Analytical Response of ISFET Sensors for Quantitative and Thermodynamic Assessment in Glacial Acetic Acid

“…However, if the overall dissociation constant for the base and the calibration parameters in the basic zone are known, then in agreement with Equation 5, it becomes possible to calculate the equilibrium constants for the perchlorates of the protonated base with the first data of the potentiometric titration for the respective base. Tables 3 and 4 show the results of the determination of the overall dissociation constants for the pyridine (PirHClO 4 ) and the diethylamine (DietHClO 4 ), taking into consideration the data for the pyridine equilibrium constants reported by Kolthoff and Bruckenstein [1] and by Kolling [20]. It should be noted that after seven assessments the calculated mean was 5.44 AE 0.03.…”

“…Some other alternative calibration methods have been considered thenceforth; namely, In 1953, Biedermann and Sille ¬ n [19] developed a method to calibrate potentiometric systems that did not use calibration patterns. Later in 1976, Kolling [20] used for the first time this calibration method for systems where the solvent was glacial acetic acid, using the equations that follow. According to the Nernst equation, the relation between the cells potential E and the activity of the ion H 2 Ac is given by:…”

Potentiometric determination of equilibrium constants of bases and perchlorates of protonated bases in glacial acetic acid using Superquad

“…In 1953, Biedermann [16] developed another method for calibration of potentiometric systems as an alternative to the use of standards. In 1976 Kolling [12] used for the first time this calibration method for systems with glacial acetic acid as solvent, the expressions for which are given considering that, from the Nernst equation, the relation between the cell potential and the activity of the H 2 Ac + ion or the Ac -ion (acid or basic medium), are given by Eqs. (7) and (8):…”

“…In his work, Kolling [12] carried out a rearrangement of Eqs. (7) and (8) in order to obtain linear functions and by fitting with linear least squares regression to the experimental data the author obtained the calibration parameters needed.…”

“…Remarkably enough, it was almost 40 years after the experiments by Bruckenstein and Kolthoff [3], that their method continues to be the only one being used for the potentiometric determination of equilibrium constants in glacial acetic acid, in spite of the work by Kolling [12], who developed an interesting method for the determination of the overall dissociation constants for bases.…”