Neutral carrier-based Na+-selective electrode for application in blood serum

Maruizumi, Takuya; Wegmann, Dorothée; Suter, Gabriela; Ammann, D.; Simon, W.

doi:10.1007/bf01206726

Cited by 44 publications

(25 citation statements)

References 16 publications

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“…Here, we only consider the case with divalent primary ions and only one type of monovalent interfering ions so that eq 3 reduces to (4) For small levels of ion-exchange with interfering ions (less than about 10%), a less complex mixed ion response equation can be used, 18 and equation 4 is simplified to: (5) Eq. 5 is rewritten for the front side of the membrane: (6) And the backside of the membrane as: (7) At steady state, the ion concentrations are usually different in each aqueous phase boundary layer at both sides of the membrane, where c ifb , c ibb represent the bulk solution concentrations of I 2+ at the front and back side of the membrane, respectively (Figure 1). We assume steadystate concentration profiles since supported thin liquid membranes are used.…”

Section: Theorymentioning

confidence: 99%

Sensitivity and Working Range of Backside Calibration Potentiometry

Ngeontae

et al. 2007

Anal. Chem.

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A new direction in potentiometric sensing, termed backside calibration potentiometry, was recently introduced. It makes use of the fact that the stir effect disappears in absence of ion-ionophore complex concentration gradient across supported liquid membrane ion-selective membranes. This method is especially suitable for measurements in which recalibration in the sample is not feasible, such as in remote monitoring applications. Here, a theoretical model is established to predict the working concentration range of the method. Lead(II)-selective Celgard membranes were used here with H + as the dominant interfering ions. The emf difference for stirred and unstirred solutions was measured and the magnitude of this emf change as a function of the sample Pb 2+ concentration was found to exhibit a bell shape that spans about three orders of magnitude. The concentration of interfering ions and the selectivity of the membrane were demonstrated to be important factors that affect the working range. Smaller ratios of primary ion concentrations at both aqueous sides of the membrane gave smaller emf difference values, and emf changes could still be observed with a logarithmic concentration ratio of 0.05. All experimental results correlated satisfactorily with the theoretical model.Ion-selective electrodes (ISEs) may provide a response to the ion activity change in the aqueous phase based on changes of the phase boundary potential at the sample/membrane interface. 1-4 Ionophore-based ISE membranes have been successfully developed for the detection of ions in complex samples such as undiluted whole blood.5 -8 In recent years, trace analysis with ISEs has become an attractive research direction, 9, 10 made possible with an improved understanding of transmembrane ion fluxes. Indeed, not only the selectivity of the ionophore but also the leaching of primary ions from the membrane to the aqueous phase boundary layer may be the limiting factor dictating the lower detection limit. [11][12][13] Despite these important advances, potentiometric sensors still rely on the magnitude of the emf for making predictions about the sample ion activity. This implies that all other potential contributions, including that at the inner and outer reference electrode, must remain constant between the time of calibration and measurement. In routine clinical analysis of physiological samples, this time is kept short by continuously recalibrating between measurements. Moreover, careful temperature control is employed because of the influence of temperature on Correspondence to:

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Section: Theorymentioning

confidence: 99%

Sensitivity and Working Range of Backside Calibration Potentiometry

Ngeontae

et al. 2007

Anal. Chem.

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“…It appeared that the MOPSO coated the glass surface of the electrode. Thus, it was necessary to use a PVC membrane neutral carrier-based NalSE (provided by Prof. W. Simon, Zürich, Switzerland [ 4 ]) for the MOPSO system. The silver-silver chloride reference electrodes were identical with those used previously in this laboratory [ 2 ].…”

Section: Methodsmentioning

confidence: 99%

“…They were about 1 mV lower than the theoretical Nernstian slopes; hence, the electrodes were not thermodynamically reversible, but were still useful for the purpose of this study. The selectivity of the two NalSEs toward the hydrogen ion requires that the pH of the solutions should be between 4.5 and 10 at the NaCl concentration of 0.01–0.1 m [ 4 , 6 ]. In this study, the pH of the solutions was 5.5–7.5, which was well within the range of requirement.…”

Section: Methodsmentioning

confidence: 99%

Investigation of the interaction of sodium chloride and two amino sulfonic acids, HEPES and MOPSO, by EMF measurements

Feng

Koch

1991

J. RES. NATL. INST. STAN.

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Ionic interactions in the two systems NaCl-HEPES (N-2-hydroxyethylpiperazine-N′-2-ethanesulfonic acid) and NaCl-MOPSO (3-(N-Morpholino)-2-hydroxypropanesulfonic acid) have been studied in terms of their mutual influence on the respective activity coefficients of each component. Activity coefficients for each component of the two systems and for corresponding buffers are calculated from emf measurements of solutions containing NaCl, the aminosulfonic acid, and its conjugate base in a NalSE/solution/AgCl-Ag cell at 5, 15, 25, and 37 °C.

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“…Previously reported Na + ion detection graphene–ISFET (G–ISFET) sensors used Ag/AgCl reference electrodes, and the sensor was a three–dimensional structure (3D) [ 14 , 17 , 18 ]. In this work, we propose a two–dimensional (2D) sensing structure, a fluorinated graphene reference electrode (FG–RE), for integration with a G–ISFET sensing device for the detection of Na + ions.…”

Section: Introductionmentioning

confidence: 99%

Two–Dimensional Disposable Graphene Sensor to Detect Na+ Ions

Jeon

Gianti

et al. 2021

Nanomaterials

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The monitoring of Na+ ions distributed in the body has been indirectly calculated by the detection of Na+ ions in urine. We fabricated a two–dimensional (2D) Na+ ion sensor using a graphene ion–sensitive field–effect transistor (G–ISFET) and used fluorinated graphene as a reference electrode (FG–RE). We integrated G–ISFET and FG on a printed circuit board (PCB) designed in the form of a secure digital (SD) card to fabricate a disposable Na+ ion sensor. The sensitivity of the PCB tip to Na+ ions was determined to be −55.4 mV/dec. The sensor exhibited good linearity despite the presence of interfering ions in the buffer solution. We expanded the evaluation of the PCB tip to real human patient urine samples. The PCB tip exhibited a sensitivity of −0.36 mV/mM and linearly detected Na+ ions in human patient urine without any dilution process. We expect that G–ISFET with FG–RE can be used to realize a disposable Na+ ion sensor by serving as an alternative to Ag/AgCl reference electrodes.

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Neutral carrier-based Na+-selective electrode for application in blood serum

Cited by 44 publications

References 16 publications

Sensitivity and Working Range of Backside Calibration Potentiometry

Sensitivity and Working Range of Backside Calibration Potentiometry

Investigation of the interaction of sodium chloride and two amino sulfonic acids, HEPES and MOPSO, by EMF measurements

Two–Dimensional Disposable Graphene Sensor to Detect Na+ Ions

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