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A chronoamperometric method to estimate ionophore loss from ion-selective electrode membranes
1Department of Chemistry, Rhodes College, 2000 North Parkway, Memphis, Tennessee 38112.
Analytical Chemistry
|June 14, 2011
Summary
A new chronoamperometric method accurately measures valinomycin concentration in ion-selective electrode membranes, even after ionophore leaching. This technique shows high precision and reliability for membrane analysis.
Area of Science:
- Analytical Chemistry
- Electrochemistry
- Materials Science
Background:
- Ion-selective electrodes (ISEs) are crucial for chemical sensing.
- Accurate quantification of ionophores within ISE membranes is essential for performance.
- Existing methods may not be suitable for analyzing membranes after ionophore leaching.
Purpose of the Study:
- To develop and validate a novel chronoamperometric method for estimating neutral ionophore concentration.
- To assess the method's accuracy and precision in poly(vinyl chloride)-based membranes.
- To determine the method's applicability to membranes with leached ionophore.
Main Methods:
- Development of a chronoamperometric technique.
- Application to valinomycin-doped dioctyl sebacate-plasticized PVC membranes.
- Analysis of freshly prepared and ionophore-extracted membranes.
- Validation using replicate measurements and comparison to true concentrations.
Main Results:
- The chronoamperometric method accurately estimated valinomycin concentration within 10%.
- Replicate measurements showed a relative standard deviation of less than 10%.
- The method successfully quantified valinomycin concentration even after leaching from the membrane.
Conclusions:
- A novel chronoamperometric method provides a reliable and precise way to quantify ionophores in ISE membranes.
- The technique is effective for analyzing membranes with varying ionophore content, including leached states.
- Preliminary results indicate no interference from blood protein adsorption, suggesting potential in biological applications.
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