This study reports a facile approach for the fabrication of chitosan (CS, biopolymer)- and l-histidine (L-His, biomolecule)-stabilized self-assembled silicon nanoparticles (SiNPs) for sensing Cu2+ ions. Approached method yielded 3.8 ± 0.04 nm size CS/L-His-SiNPs particles, with high stability against harsh pH and temperature conditions. Besides, CS/L-His-SiNPs highly selective to Copper amongst different metal ions tested (Fe3+, Mg2+, Al3+, Cr3+, Cr6+, Cu2+, Mn2+, Cd2+, Pb2+, Zn2+, Hg2+, Ca2+, Li2+, Po42-, As3+, As5+). As compared to the blank-SiNPs (LOD = 96.49 ± 0.223 μM) and CS-SiNPs (LOD = 33.35 ± 1.004 μM); L-His ligand, enhanced the sensitivity of the CS/L-His-SiNPs toward Cu2+ with remarkable LOD value of 55.02 ± 0.42 nM. Applicability of CS/L-His-SiNPs was evaluated by coating CS/L-His-SiNPs on thin layer chromatography (TLC) sheets, CS/L-His-SiNPs-TLC sheets exhibited significant sensing capacity toward Cu2+ ions, with a detection range of 4.0-900 μM, making them suitable for on-site analysis of Cu2+ ions from both environmental and clinical samples. Finally, Cu2+ sensing practicality of CS/L-His-SiNPs-TLC sheets were challenged against real human urine samples. Expressively, CS/L-His-SiNPs-TLC sheets could be regenerated using ethylenediaminetetraacetic acid (EDTA), without losing their photostability, and can be reused further.
Keywords: Blue fluorescent; Green synthesis; Ligand; On-site detection; Self-seeded; Static quenching.
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