Molecular Probe Embedded Porous Polymer Scaffold as Solid‐State Visual Sensor for Selective and Sequential Sensing of Ultra‐Trace Toxic Heavy Metal Ions in Environmental/Commercial Samples

• Published in: Advanced functional materials 2024-03, Vol.34 (11), p.n/a
• Main Authors: Sivaraman, Sushmitha P, Srinivasan, Prabhakaran, Madhu, Deepan Kumar, Chinaraga, Pitchaiah K, Rao, Brahmmananda C V S, Nagarajan, Sivaraman, Deivasigamani, Prabhakaran, Mohan, Akhila Maheswari
• Format: Article
• Language: English
• Subjects: Cadmium; Color; colorimetric; Embedding; Heavy metals; Lead; macro‐/mesopores; Mercury (metal); Optical measuring instruments; polymer monolith; Polymers; Riveting; Scaffolds; Sensors; solid‐state sensor; Surface properties; toxic ions
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202310851

The article reports on the tailor‐made solid‐state optical sensor through controlled imbuement of an amphiphilic probe onto a dual interwoven macro‐/meso‐porous polymer monolithic scaffold for the selective ocular sensing of ultra‐trace toxic heavy metal ions. The structural/surface morphology of the poly(LMC‐co‐TMP) monolith is customized through the stochiometric inclusion of lauryl methacrylate (LMC), trimethyl propanetrimethacrylate (TMP) and porogenic solvents. The riveting sensing performance of the poly(LMC‐co‐TMP) scaffolds for the target ions arises from the built‐in twofold intermingled porous architects that render voluminous surface area and porosity for the embedding of 2‐((1H‐benzoimidazol‐2‐yl)‐4‐butan‐2‐yl)phenol (HBBP), a chromoionophoric probe. The sensor's unique structural and surface properties endure stable ion‐complexation through color transitions from yellow (blank) to a leafy green, peanut brown, and dark blue for Pb2+, Hg2+, and Cd2+, respectively. The sensor imposes high binding affinity for the target ions, with a linear response range of 0–200 ppb for Pb2+/Hg2+ and 0–300 ppb for Cd2+. The detection limit values are 0.46, 0.52, and 0.41 ppb for Pb2+, Hg2+, and Cd2+, respectively. The sensor's hassle‐free on‐field testing in environmental and synthetic samples reveals excellent data reproducibility (Relative Standard Deviation (RSD) ≤1.97%), with pH‐assisted reliable color transitions for eight regenerative trials, with a response time of 45 s. The proposed solid‐state colorimetric sensor using porous polymer monolith, i.e., poly(LMC‐co‐TMP) imbuement with a chromoionophoric HBBP probe, is a simple/eco‐benign approach for trapping ultra‐trace toxins. The spatial orientation constraints of the HBBP molecules within the bimodal porous monolith offer exclusive selectivity for Pb2+/Hg2+/Cd2+, with brilliant color transitions. The parameter fine‐tuning offers rapid and reliable ion‐sensing, essential for on‐site/real‐time toxicity monitoring.