Selective Perchlorate Sensing Using Electrochemical Impedance Spectroscopy with Self-Assembled Monolayers of semiaza-Bambusurils

Raman Khurana, Fuad Alami, Christian A. Nijhuis, Ehud Keinan, Jurriaan Huskens, Ofer Reany

Research output: Contribution to journalArticlepeer-review

Abstract

In the last two decades, perchlorate salts have been identified as environmental pollutants and recognized as potential substances affecting human health. We describe self-assembled monolayers (SAMs) of novel semiaza-bambus[6]urils (semiaza-BUs) equipped with thioethers or disulfide (dithiolane) functionalities as surface-anchoring groups on gold electrodes. Cyclic voltammetry (CV) with Fe(CN)63−/4− as a redox probe, together with X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and ellipsometry, were employed to characterize the interactions at the interface between the anchoring groups and the metal substrate. Data showed that the anion receptors′ packing on the gold strongly depends on the anchoring group. As a result, SAMs of BUs with lipoic amide side chains show a concentration-dependent layer thickness. The BU SAMs are extremely stable on repeated electrochemical potential scans and can selectively recognize perchlorate anions. Our electrochemical impedance spectroscopy (EIS) studies indicated that semiaza-BU equipped with the lipoic amide side chains binds perchlorate (2–100 mM) preferentially over other anions such as F, Cl, I, AcO, H2PO4, HPO42−, SO42−, NO2, NO3, or CO32−. The resistance performance is 10 to 100 times more efficient than SAMs containing all other tested anions.

Original languageEnglish
Article numbere202302968
Pages (from-to)e202302968
JournalChemistry - A European Journal
Volume30
Issue number3
DOIs
StatePublished - 11 Jan 2024

Bibliographical note

Publisher Copyright:
© 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.

Keywords

  • anion sensing
  • bambusurils
  • electrochemical impedance spectroscopy
  • self-assembled monolayers
  • supramolecular chemistry

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