Prepared by: Prof. Madya Dr. Shahrul Ainliah Binti Alang Ahmad

Calixarenes, a class of supramolecules, are commonly employed as receptors for the identification of guest molecules and ions due to their outstanding properties. These compounds can be readily synthesised in significant amounts and can be selectively changed at their upper rim (non-polar) and lower rim (polar). Furthermore, calixarenes contain electron-rich interior cavities and can form complexes with metal ions of suitable dimensions through dipole-dipole interactions. They exist in a range of ring diameters, ranging from 4 to 8 aromatic residues. The phenolic residue number in this macrocycle is shown as an n-value (4, 6, or 8) following the term calix[n]arene. The dimensions of the chambers in calixarenes can be modified to accommodate molecular guests of different sizes as required. The capacity to adapt is essential for creating sensors that have a high level of selectivity for various analytes.

Due to their remarkable properties, strategies have been developed to immobilize calixarene derivatives on electrode surfaces to create the active sensing layer. Integrating calixarenes with composites can further enhance the performance and versatility of electrochemical sensors. Electrochemical sensors provide excellent sensitivity, selectivity, affordability, and accuracy for real-time detection of pollutants in complex environment. Additionally, there is a growing trend of miniaturisation in portable electronic technology. In our previous work, the combination of calixarenes with reduced graphene oxide and metal nanoparticles significantly enhanced the sensitivity and selectivity of the sensors, resulting in improved signal transduction and amplification. Compared to conventional techniques, the portable calixarene-based sensors hold great potential for advancing analytical technologies in water quality monitoring.

 Figure 1 Schematic diagram of the construction portable calixarene-based electrochemical sensor

References:

1. Shahrul Ainliah Alang Ahmad, Noremylia Mohd Bakhori, Jaafar Abdullah, Nor Azah Yusof, Chong Jin Mei, Nurhamizah Rahmat, Irene Ling, Development of Electrochemical Sensor Based On Array Electrodes For Heavy Metal Detection, 2021, Design Patent, Status: Approved, PI 2021007907
2. Chong, J.M.; Yusof, N. and Ahmad S.A.A.A Electrochemical Determination of Lead & Copper Ions Using Thiolated Calix[4]arene-Modified Screen-Printed Carbon Electrode Chemosensor 2021, 9,157, 1-14.
3. N. S. Zainal, S. A. A. Ahmad, L. H. Ngee and I. Ling, Development of Electrochemical sensor Based on Thiolated Calixarene Functionalized Gold Nanoparticles for The Selective Recognition of Anthracene, IEEE Sensors Journal, 2020, 21, 5.

Date of Input: 21/06/2024 | Updated: 21/06/2024 | hidayahsaleh