Chromoionophores decorated silica-polymer hybrid monolith as the solid-state optical sensor for the simultaneous detection of Pb2+, Hg2+, and Cd2+ in aqueous and cigarette samples

Abstract

This work reports on fabricating a flexible and reliable three-in-one solid-phase ocular sensor to perceive and confiscate the trace Pb2+, Hg2+, and Cd2+ using a structurally customized probe-anchored porous hybrid monolithic sensor. The dual combination of silica/polymer hybrid monolith was achieved from the bulk polymerization of 3-(trimethoxysilyl) propyl methacrylate (TSPM) and pentaerythritol trimethacrylate (PETMA), i.e., poly(TSPM-co-PETMA). The monolithic template delivered a well-ordered porous structure and greater surface area that enabled the regular impregnation of chromophoric probe (TAN), i.e., (E)-1-(thiazol-2-yldiazenyl) naphthalene-2-ol onto monolith surface for sensing target analytes under lower ppb levels. FE-SEM, HR-TEM, EDAX, SAED, p-XRD, FT-IR, TGA and N2 isotherm were deployed to characterize the structural and exterior topographies of the hybrid sensor. The geometrically frozen TAN molecules onto the hybrid monolith form a charge transfer complex with the target ions, thereby rendering a consecutive color shift from light orange to brown for Pb2+, reddish maroon for Hg2+, and purplish pink for Cd2+. The sensor offered a linear response with metal ion concentrations ranging from 0.2 to 100 ppb with lower detection limit values of 0.42, 0.50, and 0.48 ppb for Pb2+, Hg2+, and Cd2+, respectively. The hybrid sensor affords distinct ion sensitivity and selectivity towards Pb2+, Hg2+, and Cd2+ with a quick response time of ≤ 80 s of contact. Furthermore, the sensor was tested with natural samples like environmental water and cigarette samples to validate the method’s real-time monitoring ability. The resultant statistical data demonstrated that the proposed colorimetric sensor was renewable and more feasible for practical application.