Calix[4]arene Derivative-Modified Glassy Carbon Electrode: A New Sensing Platform for Rapid, Simultaneous, and Picomolar Detection of Zn(II), Pb(II), As(III), and Hg(II)

Abstract

The glassy carbon electrode was fabricated with multifunctional bis-triazole-appended calix[4]arene and then used for the simultaneous detection of Zn(II), Pb(II), As(III), and Hg(II). Before applying the square-wave anodic stripping voltammetry, the sensitivity and precision of the modified electrode was assured by optimizing various conditions such as the modifier concentration, pH of the solution, deposition potential, accumulation time, and supporting electrolytes. The modified glassy carbon electrode was found to be responsive up to picomolar limits for the aforementioned heavy metal ions, which is a concentration limit much lower than the threshold level permitted by the World Health Organization. Importantly, the designed sensing platform showed anti-interference ability, good stability, repeatability, reproducibility, and applicability for the detection of multiple metal ions. The detection limits obtained for Zn(II), Pb(II), As(III), and Hg(II) are 66.3, 14.6, 71.9, and 28.9 pM, respectively.

Carbon Dots Derived from Waste Psidium Guajava Leaves for Electrocatalytic Sensing of Chlorpyrifos

“…The straight line at lower frequencies is due to the diffusion‐controlled process at the electrode/electrolyte interface [44]. The equivalent circuit diagrams of bare GCE show an R ct of 3.69 KΩ (Figure S1b), and a decrease in R ct (2.35 KΩ) (Figure S1c) was observed after the modification of GCE with CDs which is indicative for an increased electron transfer kinetics [45].…”

Sulfur-Bridged Co(II)-Thiacalix[4]arene Metal–Organic Framework as an Electrochemical Sensor for the Determination of Toxic Heavy Metals

“…In addition, their selfassembled pore structures can accelerate the adsorption response toward HMIs, which is beneficial for the preconcentration process of HMIs. 41,42 For instance, Wang et al…”

“…In this context, it has been previously reported that electrode materials possessing large surface areas, abundant active sites, and specific responses toward HMIs are of particular interest. − From this perspective, the emergence of metal–organic frameworks (MOFs), which are assembled with structure-directing organic ligands and metal centers, has received attention for the preparation of promising electrode materials because of their open metal sites, tunable structures, and large surface areas. − Thiacalix[4]­arene-based derivatives, which possess large inner cavities and functionalized upper and lower edges, are good organic ligands for use in the preparation of metal–organic assemblies. − In these systems, the introduced functional groups, such as −SH, −NH 2 , and −COOH groups, can interact with HMIs using Lewis acid–base attractions. − Furthermore, thiacalix[4]­arene-based complexes contain abundant phenyl rings, which promote binding to HMIs through cation···π interactions. In addition, their self-assembled pore structures can accelerate the adsorption response toward HMIs, which is beneficial for the preconcentration process of HMIs. , For instance, Wang et al designed a new sulfur-containing MOF sensor that was formed by the self-assembly of calix[4]­resorcinarenes, Co­(II) cations, and 1,4-benzenedicarboxylic acid, and this sensor exhibited an excellent capture and detection performance toward HMIs . In addition, Li et al reported an electrochemical sensor that combined thiacalix[4]­arene and Co­(II) cations (Co-TCTA/GCE, GCE = glassy carbon electrode).…”