Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy, volume 307, pages 123663
The new role of dipyrromethene chemosensor for absorbance-ratiometic and fluorescence “turn-on” sensing Zn2+ ions in water-organic solutions and real water samples
Elena V Antina
1
,
Mikhail B Berezin
1
,
Publication type: Journal Article
Publication date: 2024-02-01
scimago Q2
wos Q1
SJR: 0.653
CiteScore: 8.4
Impact factor: 4.3
ISSN: 13861425, 18733557
Spectroscopy
Analytical Chemistry
Atomic and Molecular Physics, and Optics
Instrumentation
Abstract
This study presents a dipyrromethene-based sensitive and selective probe for Zn2+ ions detection in aqueous and water-organic media. The probe demonstrates absorbance-ratiometric and “off-on” fluorescent sensing for Zn2+ in a DMSO/H2O (9:1, v/v) mixture. The 2,2′,3,3′,4,4′-hexamethyl-2,2′-dipyrromethene (HL), similar to its analogs, exhibits weak fluorescence (with a quantum yield of less than 0.001). However, upon the presence of Zn2+ ions in the sensor HL solution, there is a remarkable increase (up to 200-fold) in fluorescence intensity due to the formation of a stable intramolecular chelate complex [ZnL2]. This complex formation induces a significant hyperchromic effect and a red shift (57 nm) in the characteristic absorption bands. The sensing mechanism of the probe towards Zn2+ ions was thoroughly investigated through absorbance and fluorescent titrations, molar ratio plots, 1H NMR, and DFT/TDDFT studies. The fluorescence response exhibited a strong linear relationship with Zn2+ concentration within the range of 0 to 5.7 × 10–6 mol/L. The detection limit (LOD) and limit of quantitation (LoQ) for Zn2+ were determined as 2 × 10–8 mol/L and 6.6 × 10–8 mol/L, respectively. Moreover, the probe demonstrated high selectivity for Zn2+ ions over other metal ions (Na+, Mg2+, Al3+, Cr3+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Pd2+, Cd2+, Hg2+, Pb2+). Test systems in the form of test-strips and cotton-pads were developed based on the dipyrromethene sensor for rapid “naked-eye” detection of zinc ions in water. The sensor was successfully applied for detecting Zn2+ ions in real water samples.
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