A highly sensitive fluorescent bulk sensor based on isonicotinic acid hydrazide-immobilized nano-fumed silica (fumed-Si-INAH) for detection of Hg2+ and Cr3+ ions in aqueous media

Through functionalizing of isonicotinic acid hydrazide (INAH) on to fumed silica nanoparticles, a novel fluorescent nanomaterial (fumed-Si-INAH) was synthesized and characterized using various techniques including FT-IR, SEM, and TGA. Next, interaction of the new nanofluorophore material with metal cations was studied spectrofluorimetrically. The fluorescence evaluation of fumed-Si-INAH towards a wide range of cations including Pb2+, Cd2+, Zn2+, Cu2+, Fe2+, Ca2+, Ni2+, Mn2+, Mg2+, Co2+, Na+, Hg2+, Cr3+, and K+ revealed that fumed-Si-INAH was a highly selective optical sensor for Hg2+ and Cr3+ ions in a wide range of pH in water. Thus, it was applied as a fluorescent bulk sensor for Hg2+ and Cr3+ ions. The detection limits were obtained to be 3.5 x 10(-5) and 4.2 x 10(-5) M for Hg2+ and Cr3+, respectively.