A quinazolinone based optical probe for the simultaneous determination of Fe3+and Cu2+ content in aqueous samples; An experimental and theoretical investigations

Abstract

The chemosensor “3-((1-(7-(diethylamino)-2-oxo-2H-chromen-3-yl)ethylidene)amino)-2-(4-(4-methylpiperazin-1-yl)phenyl)-2,3-dihydroquinazolin-4(1H)-one”, referred as “probe” was synthesized for the accurate quantification of Fe3+ and Cu2+ ions in various prepared samples originated from petroleum crude oil, catalyst, milk, and water. This probe serves as a naked-eye chemosensor, displaying distinct color changes in an aqueous medium, transitioning from light yellow to dark brown for Fe3+ and pale green for Cu2+ions. Remarkably, it displays exceptional dual selectivity for Fe3+ and Cu2+ ions, even in the presence of potentially interfering elements such as Na+, K+, Ca2+, Mg2+, Ba2+, Cr3+, Mn2+, Co2+, Ni2+, Zn2+, Cd2+, As3+, Sn2+, and Hg2+. Experimental assessments demonstrated the probe's high sensitivity, detecting concentrations as low as 0.017 µM for Fe3+ ions and 0.014 µM for Cu2+ ions. The 1:1 binding interaction between the probe and the metal ions was established through Job's plot, thermogravimetric analysis, and elemental analysis. Computational experiments were performed to determine the optimal geometry of the probe and its iron & copper complexes, revealing an octahedral geometry for both complexes. A comparative quantification analysis of Fe3+ and Cu2+ content across diverse aqueous samples was executed using both ICP OES and a new method. Notably, the results exhibited a favorable concordance with ICP OES outcomes, affirming the practical viability of these novel techniques for a wide range of samples.