D. T. W. Arachchi, G.I.P. Wijesekera, M.D.P. De Costa
Nov 1, 2020
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0
Influential Citations
10
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Journal
Journal of Photochemistry and Photobiology A-chemistry
Abstract
Abstract Phenanthroline is a fluorophore known for its non-fluorescent complex formation with Fe(II). We present two novel turn-off fluorescence sensors developed based on 5-amino and 5-chloro derivatives of 1,10-phenanthroline for the quantification of Fe(II) with improved sensitivity and selectivity compared to pristine phenanthroline. The fluorescence intensity of 5-amino-1,10-phenanthroline at λem 512 nm when λex 280 nm was decreased remarkably mainly due to the 1:3 static quenching by Fe(II), supported by the charge transfer spectra and the temperature studies. The formation of a stable complex with Fe(II) was observed in the range of pH 4.64 to 8.21 with a detection limit of 2.74 × 10-7 M at 3.3σ and 25 °C. The 5-chloro derivative showed much higher sensitivity and selectivity towards Fe(II) in the range of pH 3.80 to 6.80 with a detection limit of 1.70 × 10-8 M at 3.3σ and 25 °C when the λex and λem were 286 nm and 379 nm, respectively. In both the fluorescence sensors, the observed interference from foreign ions was at a minimum level, indicating the sensors’ specific selectivity towards Fe(II). The interference from cations; Cu(II), Ni(II), and Co(II) was comparatively higher, while the anions showed only a little to no interference.