Relations between Voltammetry and Potentiometric and Amperometric Titrations

Kolthoff, I. M.

doi:10.1021/ac60095a004

Cited by 44 publications

(18 citation statements)

References 13 publications

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“…This happens because at some point the bulk concentration of analyte falls to the point that the diffusion rate to the electrode cannot keep up with the imposed current. The potential rises to the point at which the cathode begins to reduce dissolved oxygen or hydrogen ions if oxygen is not present 3 . The magnitude of this error is more important for dilute solutions and, as can be seen in part D of Figure 2, can be substantial at the levels found in typical water samples.…”

Section: Resultsmentioning

confidence: 97%

“…The difference in the concentration of analyte in the bulk solution and the concentration at the electrode surface provides a driving force for diffusion to the electrode. It is this diffusion process that limits the current through the electrode, and it is a linear function of the bulk concentration of analyte 3 , 8 . At the endpoint, all analyte is consumed, so no current caused by analyte reduction can be measured.…”

Section: Resultsmentioning

confidence: 99%

“…An electrode is described as being either polarized or depolarized according to its electrochemical potential relative to the particular system in which it is placed. Kolthoff states that “an electrode is polarized when it adopts a potential impressed upon it with little or no change in current and is ideally depolarized when upon passage of current the potential does not deviate from its reversible value.” 3 When reactants in a reversible system, such as iodine–iodide, react at an electrode, the local concentrations of reactants and products are determined by the potential of the electrode. When neither substance is limiting (i.e., the current is only limited by the conductivity of the solution), the concentrations will be close to those in the bulk solution, and the electrode will be depolarized.…”

Section: Amperometric Titration Conceptsmentioning

confidence: 99%

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Titration of Chlorine: Amperometric versus Potentiometric

Hernlem¹,

Tsai²

2000

Journal AWWA

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CHLORINE:amperometric versus potentiometric imple, reliable, inexpensive, and accurate methods are needed for determining oxidizing species of chlorine and chlorine dioxide in water contaminated with other materials. These compounds are used as chemical disinfection agents in food-processing waters. These processing waters, which include fruit and vegetable washing and conveying fluids and poultry chiller water, normally contain substantial quantities of organic material and turbidity.Amperometric titration is a useful analytical tool that is widely considered one of the most reliable and sensitive techniques for quantifying chlorine in water samples. 1 It differs from the alternative spectrophotometric methods commonly used, which are rendered inoperative by variations in absorptivity in anything but "clean" water. However, there is much confusion about the different methods of endpoint detection. In addition, terms like "polarized," "depolarized," and "applied potential" are not always used consistently. Some manufacturers of S The ability to accurately measure chlorine or other disinfectants in water is important for control of microorganisms. Whereas amperometry is specified for chlorine in Standard Methods for the Examination of Water and Wastewater, manufacturers of automatic titrators are marketing their potentiometric devices for such titrations. In this article, the electrochemical basis for amperometric and potentiometric endpoint detection is examined, and two amperometric and two potentiometric methods are compared. Both amperometric methods are shown to be superior to potentiometric endpoint detection and amenable to automatic titration. Finally, fundamentals of amperometry are discussed, and the simple circuit that was used to perform amperometric titrations using a modified automated pH/potentiometric titrator is presented.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Section: Amperometric Titration Conceptsmentioning

confidence: 99%

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Titration of Chlorine: Amperometric versus Potentiometric

Hernlem¹,

Tsai²

2000

Journal AWWA

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“…The history of electroanalysis started not much later than that of electrochemistry, just when analytical chemists discovered that the new quantitative laws such as these by Nernst or Faraday could be effectively used to provide information about the chemical composition of samples [8]. From these early times, two separated branches arose: on the one hand, potentiometry focused on thermodynamics and potentials and, on the other hand, amperometry and voltammetry focused on kinetics and currents [10]. It is the classical antagonism between the static view of the universe by Parmenides ("change is impossible") and the dynamic view by Heraclitus ("everything flows").…”

Section: Prehistory and History: The Age Of Metalsmentioning

confidence: 99%

Electroanalysis from the past to the twenty-first century: challenges and perspectives

Dı́az-Cruz

Serrano

Pérez‐Ràfols

et al. 2020

J Solid State Electrochem

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“…Both macro and mieroseale determinations can be performed using various methods of end point detection. The most frequently used methods are visual, dead-stop [9][10][11][12], eoulometrie [13][14][15][16], and potentiometric [17][18][19][20].…”

mentioning

confidence: 99%

Enthalpimetric assay of the water content of some oils and fats

Bark

Hadipranoto

1991

Journal of Thermal Analysis

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A rapid and accurate direct injection enthalpimetric (DIE) method has been developed for the determination of the water content in some oils and fats of commercial interest. The method combines the DIE and the Karl Fischer Reagent procedures and is calibrated against real samples whose water content have been determined by a standard distillation method using toluene as the immiscible solvent. The reproducibility and precision are equivalent to those of the standard method for the water content of materials such as soya bean oil. The procedure is able to determine water contents in compounds such as lard, which cannot be determined by the Dean & Stark method. Once calibrated, the proposed method can be operated routinely by semi-skilled personnel. The main advantages of the method are those of time and the cost of analysis.Chemically, the principal roles of water in foods include: (a) solvent, (b) reaction medium, (c) reactant, (d) antioxidant, (e)pro-oxidant, (f) a component of intramolecular structure and intermolecular structure [1]. Consequently, an ability to determine the water content is vital in ascertaining stability and thermal behaviour in connection with the processing and the packaging of foodstuffs.Many industrial food processes require reliable quantitative methods for the determination of moisture or water since water enters directly or indirectly into many chemical reactions. In response to this widespread need for reliable analysis, a wide array of methods [1][2][3] is presently available to cover the range of water content from parts per billion to high percentages by weight and volume, but all, even the widely used Karl-Fischer Reagent technique, suffer some limitations. Thus, a study of a new technique, such as Direct Injection Enthalpimetry is potentially of great interest to the analytical chemist.

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Relations between Voltammetry and Potentiometric and Amperometric Titrations

Cited by 44 publications

References 13 publications

Titration of Chlorine: Amperometric versus Potentiometric

Titration of Chlorine: Amperometric versus Potentiometric

Electroanalysis from the past to the twenty-first century: challenges and perspectives

Enthalpimetric assay of the water content of some oils and fats

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