MOFs-based dual-emission stable fluorescent/colorimetric probe for efficient identification and screening of trace Hg2+, In3+, Zr4+

This study presents a novel method for simultaneous identification of Hg 2+ , In 3+ , and Zr 4+ ions in solution using a double-emission fluorescence MOFs composite (EY@MOF-1) as a probe. The new pure zinc-based metal-organic framework ({[Zn 3 (TPPO) 2 (1,4-IYI) 2 ]·3H 2 O} n , MOFs-1, Tri( p - carboxyphenyl) phosphorus oxide = H 3 TPPO,1-(4-imidazol-1-ylphenyl)-imidazole = 1,4-iyi, Eosin Y = EY) produces strong single emission fluorescence at 364 nm when excited at 320 nm. Utilizing its unique fluorescent properties, MOFs-1 can effectively identify Hg 2+ , In 3+ , and Zr 4+ ions in solution. However, the fluorescence quenching effect caused by the three ions is identical, making it impossible to accurately determine which metal is the identified ion. To address this issue, a post-modification synthesis strategy was used to construct EY doped dual-emission fluorescent material EY@MOF-1. As expected, EY@MOF-1 can effectively identify and differentiate Hg 2+ , In 3+ , and Zr 4+ ions in solution based on their different fluorescence quenching changes. The probe has a limit of detection of 0.18 μM (Zr4+), 0.20 μM (In3+), and 0.13 μM (Hg2+) within a certain concentration range. The mechanism of fluorescence recognition was investigated in depth. This double emission fluorescence probe, with its high sensitivity and selectivity, is the first of its kind and provides a simple and reliable method for effective identification of Hg 2+ , In 3+ , and Zr 4+ . It has potential applications in environmental monitoring and is a valuable tool for ion identification.