A near edge X-ray absorption fine structure (NEXAFS) study of the response mechanism of the iron (III) chalcogenide glass membrane ion-selective electrode

• Proof of electron transfer and ion exchange with the iron(III) ISE.
• NEXAFS can detect low surface concentrations of electrochemically active species.
• Presence of iron(II) and iron(III) in the MSL of the iron(III) ISE.

We have utilized synchrotron radiation-X-ray photoelectron spectroscopy (SR-XPS) and near edge X-ray absorption fine structure (NEXAFS) to demonstrate unequivocally that the modified surface layer (MSL) of the iron chalcogenide glass ion-selective electrode (ISE) comprises a mixture of iron(II) and iron(III) redox states, as proposed in previous theories to explain the mixed electron transfer and ion exchange response mechanism of this analytically important ISE.

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