Flow-injection approach for the determination of the dynamic response characteristics of ion-selective electrodes. Part 1. Theoretical considerations

doi:10.1016/S0003-2670(00)83537-0

Analytica Chimica Acta

Volume 234, 1990, Pages 49-56

https://doi.org/10.1016/S0003-2670(00)83537-0 Get rights and content

Abstract

A single-line flow-injection system with a straight tube reactor is proposed for investigating the dynamic response behaviour of ion-selective electrodes. The principle of the method is based on the fact that the concentration—time curve at the electrode surface can be described theoretically in the flow-injection system under certain practically realizable conditions. The response of the ion-selective electrode to that input signal can be measured experimentally. Thus, knowing the input and the output signal of an ion-selective electrode, an appropriate model describing its dynamic behaviour can be selected among the relevant models existing in the literature. Theoretical expressions for predicting the transient response of ion-selective electrodes in the flow system when the rate-determining step is an ion-transport process through a diffusion layer or a kinetic process were elaborated.

References (31)

K. Tóth et al.
Anal. Chim. Acta
(1986)
S.D. Kolev et al.
Anal. Chim. Acta
(1986)
J.T. Vanderslice et al.
Talanta
(1981)
S.D. Kolev et al.
Anal. Chim. Acta
(1988)
S.D. Kolev et al.
Anal. Chim. Acta
(1988)
E. Lindner et al.
J. Electroanal. Chem.
(1989)
S.D. Kolev et al.
Anal. Chim. Acta
(1987)
J.M. Reijn et al.
Anal. Chim. Acta
(1981)
K. Tóth et al.
Anal. Chim. Acta
(1971)
E. Lindner et al.
(1988)

R.P. Buck

Ion-Sel. Electrode Rev.

(1982)

K. Cammann et al.

A. Bezegh et al.

Anal. Chem.

(1987)

M.L. Iglehart et al.

Anal. Chem.

(1988)

M.L. Iglehart et al.

Anal. Chem.

(1988)

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A general mathematical model of a flow-through optical chemical sensor prepared by the immobilization of 1-(2′-pyridylazo)-2-naphthol (PAN) into a commercial Nafion^® membrane was developed. The model takes into account the preparation of the optode membrane and in our opinion the most important chemical and physical processes involved in the generation of the analytical signal. The following model parameters were determined separately from the experimental verification of the model: aqueous diffusion coefficient of CuSO₄ – 8.75 × 10⁻¹⁰ m² s⁻¹; membrane self-diffusion coefficient of the Cu²⁺–PAN complex and Cu²⁺ – 1.87 × 10⁻¹⁶ and 6.00 × 10⁻¹⁵ m² s⁻¹, respectively; Nafion/water ion-exchange equilibrium constants for the Cu²⁺–PAN complex and Cu²⁺ – 109.2 and 3.65 × 10⁻³, respectively. Very good agreement was obtained between the experimental optode response and the model predictions thus showing that the model developed could be used successfully for the mathematical description and optimization of the PAN/Nafion optode as well as of other ion-exchange membrane based optodes having a similar response mechanism.
Chapter 3 Theoretical Basis of Flow Injection Analysis
2008, Comprehensive Analytical Chemistry
Citation Excerpt :
This model has been solved for a step-function change in the concentration of the analyte in the flow cell, and therefore it can only describe the rising section of the corresponding FIA peaks. Kolev et al. [93] have developed a model of an FIA system incorporating an iodide ion-selective electrode. The mass transfer of the analyte to the measuring cell in this model is described by the ADPFM (Equation (8)).
This chapter focuses on the mass transfer processes in flow injection analysis (FIA) and their effect on the generation of the analytical signal. An FIA system can be considered an assembly of subsystems, tied up together by common flows of materials. The performance of such a system is determined by the characteristics of the individual subsystems and also by their interactions and interrelations. The main subsystems of a typical FIA system describe (1) mass transfer phenomena, (2) chemical kinetic phenomena, and (3) the sensing mechanism involved in producing the analytical signal. All three subsystems act in unison and thus are equally important for the functioning of any FIA system. The mass transfer subsystem is primarily responsible for defining the residence time distribution (RTD) function or curve of an FIA system. The chemical reactions involving the analyte often take place in the conduits of FIA systems and therefore play a crucial role in the generation of the analytical signal. Most models that take into account a surface sensing mechanism are distributed parameter analytical-experimental models. The suitability of FIA for studying the dynamic behavior of chemical sensors is also demonstrated.
Validation of the membrane composition effect on the flow-injection signal profile of chalcogenide-based ion-selective sensors: A model study using electrochemical approach Hg(II) flow-injection detector case
2003, Analytica Chimica Acta
Citation Excerpt :
In the particular case of ion-selective detection, the electrochemical properties of the sensors incorporated in the detector cell play a predominant role [13–15]. This fact was made use of by Kolev et al. to propose a single-line FI-system with straight tube reactor for investigating the dynamic response behavior of ion-selective detectors [16,17]. The positive side of the observed phenomenon has been also favourably used quite recently [18] to obviate the severe chloride interference with the Cu(II) electrode function of chalcogenide based Cu(II) - ISEs by substituting the equilibrium with transient mode of signal measurement.
The membrane composition effect on signal profile of the combined ISE-flow-injection system is examined on the example of Hg(II) flow-injection potentiometric (FIP) detector based on the secondary response to Hg(II) of different thin layer silver chalcogenide membranes, obtained by cathodic electrodeposition at controlled potential. The potential of the electrochemical approach to produce a great diversity of membrane compositions and the possibility for fine tuning of their stoichiometry made it possible to select the stoichiometry with respect to silver (intrinsic defects factor) and the inclusion of dopant (extrinsic defects factor) as the two variable composition parameters. The following membranes have been tested: Ag₂Se_1−xTe_x, Ag₂Se, Ag_2+δSe and Ag_2+δSe_1−xTe_x (δ=0.24). The experimental conditions have been varied in a wide range to include four flow-rates (within the 2.5–6 ml min⁻¹ interval), and three typical carrier compositions to which either Ag(I) or Hg(II) have been added as pilot ions. The results obtained in this study show unambiguously that the membrane composition factors are an important figure of merit, the weight of which in some particular cases can be co-measurable with that of the flow manifold factors. A new important information concerning the active role of the “pilot ion” added to the carrier in controlling the rising part of the signal, through changing the membrane response rate order, is also provided.
Derivative dynamic response of ion-selective electrodes. Application to the precipitate-based iodide-selective electrode in the presence of interfering ions
1995, Analytica Chimica Acta
The concept of the derivative dynamic response (dE/dt) of ion-selective electrodes is introduced to study the response of a precipitate-based iodide-selective electrode in the presence of interfering ion, using a flow injection system and a flow-through cell. A type of concentration perturbation is assayed in which the primary ion is completely removed while the interfering ion is introduced. The effects of interfering ion concentration and flow rate on the derivative dynamic signals are studied. A new well-defined peak appears in the presence of bromide interfering ion. The peak height increases with bromide concentrations in the range of 10⁻⁵ to 10⁻² M. In the case of chloride interfering ion the new peak is only appreciable at ≥ 10⁻² M.
Mathematical modelling of flow-injection systems
1995, Analytica Chimica Acta
Analysis of the great variety of flow-injection (FI) manifolds used in analytical practice nowadays has shown that most of them can be decomposed into two basic flow configurations, i.e., the single-line and the conjugated two-line system. The former system has one influent and one effluent stream through which it can contact with the environment. The conduit walls are totally impermeable. The most distinctive characteristic of a conjugated two-line system is the existence of a flow-through section with two separate streams (e.g., donor and acceptor) which exchange matter continuously along a common semipermeable interface (e.g., membrane). It can be concluded that two of the cornerstones in the modelling of FI manifolds are the successful mathematical description of the two basic flow systems mentioned above. Numerous mathematical models of FI systems employing ideas from different scientific areas (e.g., statistics, chemical engineering, artificial intelligence, chromatography) have been developed so far. It should be pointed out that the majority of them describe only single-line FI systems. A classification of all these models based on the main principles on which they are built, is proposed. The models have been compared with respect to their predictive power, the complexity of their mathematical treatment, and the requirements for computation time when applied to single-line and conjugated two-line FI systems. It is concluded that the axially dispersed plug flow model deserves special attention because it offers an acceptable compromise between the conflicting requirements for maximal possible mathematical simplicity and maximal possible precision. It can be used as the basis for an unified approach to the modelling of FI systems.
Evaluation of a mathematical model to simulate dynamic response of tubular potentiometric sensors in flow-injection systems
1993, Sensors and Actuators: A. Physical
Potentiometric detectors based on ion-selective electrodes are specially suited to flow measurements because of their low cost and high selectivity. Simultaneously in flow analysis the use of tubular-electrode configuration seems ideal as the flow characteristics can be kept constant throughout the system. The design of very simple manifolds, which increases the robustness and the system reliability, is constrained by the knowledge of the influence of hydrodynamic parameters in the detector response. With the aim to optimize the design of this kind of systems a mathematical model, that simulates the response of tubular potentiometric detectors in flow-injection systems, has been developed and tested. Results provided by simulation are compared with experimental ones, and the model capabilities are discussed.

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Flow-injection approach for the determination of the dynamic response characteristics of ion-selective electrodes. Part 1. Theoretical considerations

Abstract

Anal. Chim. Acta

Anal. Chim. Acta

Talanta

Anal. Chim. Acta

Anal. Chim. Acta

J. Electroanal. Chem.

Anal. Chim. Acta

Anal. Chim. Acta

Anal. Chim. Acta

Ion-Sel. Electrode Rev.

Anal. Chem.

Anal. Chem.

Anal. Chem.