Dual-channel sensing platform based on MABA-Si functionalized core-shell-shell rare-earth vanadates for highly sensitive sensing of Hg2+ and Cu2+

Core-shell-shell SiO 2 @LaVO 4 :RE@SiO 2 -MABA-Si microspheres enable dual-probe Hg 2+ /Cu 2+ detection. • Detection limits of 0.14 µM for Hg²⁺ and 92.96 nM for Cu 2+ with 8–20 min response time. • IFE coupled with coordination governs selective quenching of Eu 3+ (616 nm) and Tb 3+ (543 nm) emission. • Robust performance across pH 3.0–12, 7 days stability, and 98–103.83% real-water recoveries. A dual-channel sensing system based on core-shell-shell SiO 2 @LaVO 4 :RE@SiO 2 -MABA-Si (RE = Eu, Tb) microspheres was developed for the selective detection of Hg 2+ and Cu 2+ in aqueous media. The microspheres were synthesized by grafting MABA-Si onto SiO 2 @LaVO 4 :RE@SiO 2 , yielding a triple-layered architecture (~105 nm SiO 2 core, ~4 nm LaVO 4 :RE luminescent shell, ~14 nm SiO 2 -MABA-Si functional shell). Sensing relies on the inner filter effect (IFE) coupled with synergistic coordination: MABA-Si captures Hg 2+ or Cu 2+ , and the resulting metal-ligand complexes quench the Eu 3+ (616 nm) or Tb 3+ (543 nm) emission, respectively. The Tb 3+ -based probe detected Cu 2+ with a limit of 92.96 nM and an 8 min response, while the Eu 3+ -based probe detected Hg 2+ with a limit of 0.14 μM and a 20 min response. The Hg 2+ system showed reversible "on-off-on" switching with L -cysteine. The SiO 2 shell maintained stable luminescence over pH 3.0 −12 and 7 days storage. Real water tests gave recoveries of 99 −103.83% (Hg 2+ ) and 98 −102.50% (Cu 2+ ) with RSDs below 2.4%. This platform offers a practical approach for dual-ion heavy metal monitoring. Download: Download high-res image (253KB) Download: Download full-size image