Carboxamide: based chemosensor grafted on SBA-15 nanostructure for selective detection of Hg2+ ion in an aqueous solution

A new adeninecarboxamide ligand, N-(9 H-purin-6-yl) pyridine-2-carboxamide (H₂pzac) has been synthesized by a green chemistry method using tetrabutylammunium bromide (TBAB) ionic liquid as an environmentally friendly reaction medium. The H₂pzac ligand was anchored on modified SBA-15-Cl and utilized for detection of Hg²⁺ in aqueous solution. The as-constructed SBA-15@Hpzac sensor shows a high specific surface area as well as pore volume of 250 m²/g and 0.54 cm³/g, respectively. The fluorescence assessment indicated that the designed SBA-15@Hpzac sensor presented highly sensitive and selective behavior to Hg²⁺ ion over different cations including Zn²⁺, Ni²⁺, Co²⁺, Cu²⁺, Mn²⁺, Pb²⁺, Ba²⁺, Mg²⁺, Ca²⁺, Na⁺, Fe³⁺, Fe²⁺, Al³⁺, Cd²⁺ and K⁺. The fluorescence response of the SBA-15@Hpzac sensor for selective detection of Hg²⁺ ion is excellent with detection limit (LOD) of 1.07 × 10^− 6 M. The application of the SBA-15@Hpzac sensor in determination of Hg²⁺ ions in two real water samples was also investigated.