Suppression of interfering ions by using ionic liquid and micelle moieties in spectrofluorimetric analysis of manganese


Abstract: Eosin-Y exhibits high affinity and emission based spectral response to most of the major ions in water samples. In the present study we performed selective spectrofluorimetric analysis of manganese with eosin-Y in the presence of potential interferents. We employed green chemistry reagents, ionic liquids (ILs) and two different micelles, to suppress the effect of conventional cations and anions on the response of eosin-Y. The experimental data revealed that different test moieties caused enhanced analytical response to Mn$^{2+}$. The highest analytical signal of eosin-Y was obtained in the presence of Triton X-100 at a concentration of 2.0 $\times $ 10$^{-3}$ mol L$^{-1}$. Presence of the green chemistry reagents ILs enhanced the limit of quantification for Mn$^{2+}$ 10-fold with respect to the IL-free moieties. The interfering effects of the metal ions of Ca$^{2+}$, Cu$^{2+}$, Hg$^{+}$, Hg$^{2+}$, As$^{5+}$, Li$^{+}$, Al$^{3+}$, Cr$^{3+}$, Co$^{2+}$, Ni$^{2+}$,$^{}$ and the anionic groups were completely suppressed in the presence of the ILs and micelles. Additionally, the tolerance limit of Na$^{+}$ and Zn$^{2+}$ ions increased 6-fold in the presence of IL and sodium dodecyl sulfate. The presented method did not use any harmful conventional solvents and was employed successfully for the detection of Mn$^{2+}$ ions in real water samples.

Keywords: Ionic liquids, micelle, eosin-Y, Mn$^{2+}$

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