Chemical sensors for bedside monitoring of critically ill patients

Collison, Michael E.; Meyerhoff, Mark E.

doi:10.1021/ac00206a001

Cited by 47 publications

(29 citation statements)

References 15 publications

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“…The corresponding equilibrium constant Kexch depends on the stability constants /3 of the cation/ ionophore complexes and on the ionic distribution coefficients k as follows:' (6) where the activities a; of species i refer to the aqueous solution, and the concentrations [i] refer to the membrane, which is assumed to behave as an ideal phase with activities that are identical to the concentrations.…”

Section: Kl+(org)+h+(aq)+l(org) K+(aq)+hl+(org)+l(org)mentioning

confidence: 99%

Characterization of Potassium-Selective Optode Membranes Based on Neutral Ionophores and Application in Human Blood Plasma

et al. 1990

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Section: Kl+(org)+h+(aq)+l(org) K+(aq)+hl+(org)+l(org)mentioning

confidence: 99%

Characterization of Potassium-Selective Optode Membranes Based on Neutral Ionophores and Application in Human Blood Plasma

et al. 1990

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“…Indeed, these sensors are routinely used in all types of clinical analyzers to determine electrolyte concentrations in blood and other physiological samples [13,14]. Potentiometric microelectrodes are used in physiology for single cell electrolyte detection [15].…”

Section: The Trouble Of Direct Potentiometrymentioning

confidence: 99%

Beyond potentiometry: Robust electrochemical ion sensor concepts in view of remote chemical sensing

Bakker

Bhakthavatsalam

Gemene

2008

Talanta

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For about one hundred years, potentiometry with ion-selective electrodes has been one of the dominating electroanalytical techniques. While great advances in terms of selective chemistries and materials have been achieved in recent years, the basic manner in which ion-selective membranes are used has not fundamentally changed. The potential readings are directly co-dependent on the potential at the reference electrode, which requires maintenance and for which very few accepted alternatives have been proposed. Fouling or clogging of the exposed electrode surfaces will lead to changes in the observed potential. At the same time, the Nernst equation predicts quite small potential changes, on the order of millivolts for concentration changes on the order of a factor two, making frequent recalibration, accurate temperature control and electrode maintenance key requirements of routine analytical measurements. While the relatively advanced selective materials developed for ion-selective sensors would be highly attractive for low power remote sensing application, one should consider solutions beyond classical potentiometry to make this technology practically feasible. This paper evaluates some recent examples that may be attractive solutions to the stated problems that face potentiometric measurements. These include high amplitude sensing approaches, with sensitivities that are order of magnitude larger than predicted on the Nernst equation; backside calibration potentiometry, where knowledge of the magnitude of the potential is irrelevant and the system is evaluated from the backside of the membrane; controlled current coulometry with ionselective membranes, an attractive technique for calibration free reagent delivery without the need for standards or volumetry; localized electrochemical titrations at ion-selective membranes, making it possible to design sensors that directly monitor parameters such as total acidity for which volumetric techniques were traditionally used; and controlled potential coulometry, where all ions of interest are selectively transferred into the ion-selective organic phase, forming a calibration free technique that would be exquisitely suitable for remote sensing applications. KeywordsIon-selective electrodes; chemical sensors; reference electrode; calibration free; coulometry; remote sensing Direct Potentiometry: The State of the Art and Promise for Remote SensingIon-selective electrodes are among the oldest known types of chemical sensors [1]. In most cases, an ion-selective membrane separates the sample from an inner solution, and the electromotive force between reference electrodes in the aqueous sample and the inner solution Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the p...

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“…If the sensor is to be implanted in vivo, then the biocompatibility of the materials from which the sensor is constructed must be accounted for [26,27]. More often, however, these sensors are used in clinical analyzers where they contact physiological fluids for short durations in vitro [28]. In these situations, more relevant concerns are the extent of non-specific protein interactions with the polymerbased sensing layer and with the ionophore itself.…”

Section: Mc3-based Ises For Blood Measurementsmentioning

confidence: 99%

Electronic Effects on the Selectivity of Mercuracarborand Ionophores in Ion‐Selective Electrodes and Membrane Formulations for Their Use in High Protein Concentration Environments

et al. 2003

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Ion-selective electrodes based on the ionophore [9]mercuracarborand-3 (MC3) have been demonstrated in the past to be highly selective for the chloride ion. This ionophore is macrocyclic and possesses Lewis acidic mercury centers, both of which result in enhanced ionophore binding to spherical anions. Like their charge-reverse analogs, crown ethers, mercuracarborands offer the possibility to tune binding selectivity through changes in cavity size and/or via the incorporation of functional groups onto the cavity framework. Indeed, this article outlines the effect on ionophore selectivity that results from the addition of methyl groups to the MC3×s carborane cages. Our results indicate that this simple functionalization leads to significant changes in selectivity that can be attributed to electronic effects. Furthermore, since MC3-based electrodes and optodes have previously shown sufficient selectivities to perform physiological analysis, the effect of protein backgrounds and mild exposure to human whole blood on the response of mercuracarborand ISEs is also reported.

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Chemical sensors for bedside monitoring of critically ill patients

Cited by 47 publications

References 15 publications

Characterization of Potassium-Selective Optode Membranes Based on Neutral Ionophores and Application in Human Blood Plasma

Characterization of Potassium-Selective Optode Membranes Based on Neutral Ionophores and Application in Human Blood Plasma

Beyond potentiometry: Robust electrochemical ion sensor concepts in view of remote chemical sensing

Electronic Effects on the Selectivity of Mercuracarborand Ionophores in Ion‐Selective Electrodes and Membrane Formulations for Their Use in High Protein Concentration Environments

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