Abstract:

Sensing of metal ions using fluorometric tools has wide applications in chemical, biological and environmental analysis. Plant phytochemicals, like flavonoids, exhibit intense fluorescence upon excitation by UV light. Leaves sage (Salvia officinalis), which is rich in polyphenolic and flavonoids compounds, were extracted using Soxhlet and microwave-assisted extractors. The extraction methods led to variations in the phytochemical composition of the extracts, which in turn affected their interaction with metal ions. Despite the variations in the composition, both of the extracts gave high fluorescence emissions when excited at 365 nm. Variations in fluorescence emissions of the extracts were studied in upon addition of each metal ion;  i.e., Li+, Na+, K+, Cs+, Be2+, Mg2+, Sr2+, Ba2+, Al3+, Tl3+, Ge4+, Sn4+, Pb2+, Sb3+, Bi3+, Se4+, Cu2+, Ag+, Zn2+, Cd2+, Ti4+, Cr3+, Cr6+, Mo6+,  W6+, Mn2+, Fe3+, Ni2+, Co2+ and Pd2+. When they were added into the Soxhlet extract, some ions (Cr3+, Pb2+, Co2+) induced intense fluorescence and some (Ge4+, Mg2+, K+, Na+) ions quenched the fluorescence emission. As for microwave-assisted extract, the addition of Sr2+, Mg2+ and Co2+ ions enhanced the fluorescence emission of the extract, but Fe3+, Be2+ and Cs+ lowered the fluorescence intensity. However, the results of the study should be considered as introductory and further selectivity and sensitivity studies should be done for each extract if they are used for sensing of metal ions. Yet, this study demonstrated that sage extracts has a potential for fluorescent sensing of certain metal ions.

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