Nona Semana Integrada do Instituto de Física de São Carlos

Turn-on fluorescence study of a highly selective chemosensor for Zn2+

Não agendado

20m

Iniciação Científica

Palestrante

Danyellen Dheyniffer Monteiro Galindo (Instituto de Física de São Carlos, Universidade de São Paulo,)

Descrição

Chemical sensors for molecules, ions or protons are intensively investigated due to their potential applications in many areas such as analytical chemistry, biology and environmental sciences. (1) The fluorescence sensing is attractive high selectivity, low cost compared to other devices, fast response and low detection limit particularly to essential or hazardous metal ions such as Cu, Zn, Hg and Cd for example. It was constructed a chemosensor using a 4,5-bis(aminomethyl)acridine) called LN as organic molecule, in order to detect Zn(II) in aqueous media. The linear properties of the molecule was obtained by a solution of LN dissolved in methanol with a molar concentration of 1x10-3 Molar. Linear absorption and fluorescence emission were performed with a spectrophotometer and fluorimeter in order to determine the excitation spectral region and its emission response. Both measurements were fundamental to indentify the spectral window of detection. In addition, fluorescence quantum yield (FQY) was determined by using well-known Brouwer´s method. (2) This photophysical property is important to quantify the level of sensitivity of the fluorosensor. After this characterization, LN fluorosensor was tested at different aqueous solutions containing different types of metallic cations, such as: Cu, Hg, Cd, Pb, Zn and etc. (3) The results shown that LN fluorosensor was only selective for Zn2+, in which FQY have increased of about 230%. For other cations, the FQY was kept the same as LN alone. The study and characterization of this fluorosensor may help to detect metallic ions in very low quantities in aqueous solutions. Also, one can determine the presence of metals in other systems as in cellular activities, physiological processes and, the most important, detection in the environment that comes from mining activities and industry.

Referências

1 SIVARAMAN, G. et al., Chemically diverse small molecule fluorescent chemosensors for copper ion. Coordination Chemistry Reviews, v. 357, p. 50-104, Feb. 2018. doi: 10.1016/j.ccr.2017.11.020.
2 BROUWER, A. M. Standards for photoluminescence quantum yield measurements in solution. Pure and Applied Chemistry, v. 83, n. 12, p. 2213-2228, 2011.
3 NOULAS, C.; TZIOUVALEKAS, M.; KARYOTIS, T. Zinc in soils, water and food crops. Journal of Trace Elements in Medicine and Biology, v. 49, p. 252-260, Sept. 2018. doi: 10.1016/j.jtemb.2018.02.009.