Acridine‐Thiosemicarbazones‐Stabilized Silver Nanoparticles as a Selective Sensor for Copper(II)‐Ion in Tap Water

Abstract

Environmental pollution due to heavy metals ions is becoming a serious threat to human health. In this study, we have synthesized acridine‐thiosemicarbazones‐stabilized silver nanoparticles (AT‐AgNPs) to explore their cation sensing ability and selectivity for detection copper(II)‐ion in aqueous system. Newly synthesized nanoparticle were characterized using various spectroscopic techniques such as ultraviolet–visible, Fourier‐transform infrared (FTIR), atomic force microscopy (AFM) and Zetasizer. The average size of the highly robust AT‐AgNPs was found to be in the range of 70–90 nm. The photophysical potential of AT‐AgNPs was explored using ultraviolet–visible spectroscopy. Addition of copper(II)‐ion induce significant quenching in the absorption intensity of AT‐AgNPs, whereas all other tested metals did not produce any detectable change in the UV‐visible spectrum. Further, the limit of detection (LOD) was determined by employing standard deviation method which is found to be 1 μM with a R2 equal to 0.9931. The synthesized AT‐AgNPs were highly selective for copper(II)‐ion in presence of other interferents like salts, and other metal ions. Moreover, the AT‐AgNPs were effectively and efficiently employed for the same purpose in tap water.

Functionalizing Thiosemicarbazones for Covalent Immobilization on Nanoparticles

“…In contrast to this, the idea of binding metal-TSC complexes or [drug-TSC] conjugates to surfaces of NP is new [41][42][43]. The potential suitability of TSCs to serve as ligands for metal coordination covalently anchored on NP surfaces and conjugating them to further functional units at the same time, is obvious from the up to four possible substituents on both the N1 and N4 functions of the general TSC R1R2C=N(1)-NH-C(S)-N(4)R3R4 backbone (Scheme 1A and B, marked in green) and from the modular synthesis from the R3-and R4-substituted thiosemicarbazides and any R1-and R2substituted carbonyl (Scheme 1D, blue and red marking, respectively).…”

“…In contrast to this, approaches for covalent binding of TSC onto NP are scarce. Till recently, only the condensation of citratefunctionalized Au NP with p-methyl-carbohydrazonethioamide [41] was reported, while the binding of a phenolate-acridine-TSC molecules on an Ag NP surface is depending on the coordination of this molecule on the surface and not on covalent bonds [42]. In a very recent approach, Fe3O4@SiO2 coreshell NP were reacted subsequently with (3-chloropropyl)trimethoxysilane (CPTMS), 4hydroxyacetophenone, thiosemicarbazide, and CuSO4 .…”