title: Effects of ionic liquids on fluorescence characteristics of 17α- and 17β-estradiol.
abstract: Herein, we report the effects of six different room temperature ionic liquids (RTILs) on fluorescence spectra of 17α-estradiol (EE1) and 17β-estradiol (E2). The selected RTILs belonged to the compound classes of 1-alkyl-3-methylimidazolium tetrafluoroborate ([C(n)MIM]BF(4)) and 1-alkyl-3-methyl imidazolium hexafluorophosphate ([C(n)MIM]PF(6)). RTILs had a gradual quenching effect on fluorescence intensity (FI) of EE1 and E2, and the quenching process followed the well-known Stern-Volmer theory. The quenching mechanism of EE1 and E2 by RTILs was demonstrated to be dynamic quenching. Additionally, the overall quenching efficiency by [C(n)MIM]BF(4) was higher than [C(n)MIM]PF(6). The increased carbon chain length of RTILs did not lead to obvious differences in FI for EE1 and E2. The quenching efficiency showed irregular trend at three different temperatures (25, 35 and 45 °C). RTILs such as [C(4)MIM]PF(6) had the different fluorescent effects on organic chemicals with different fluorophores. The enhancing effects of [C(4)MIM]PF(6) were observed on strong fluorescence chemicals (dansyl chloride, rhrodamine B, 1,10-phenanthroline, norfloxacin), while quenching effect on weak fluorescence chemicals (EE1 and E2). In theory, these results provide a theoretical foundation for deep insight into their interaction mechanism between RTILs and estradiol.
authors.affiliation: School of Life Sciences, Wenzhou Medical College, University-Town, Wenzhou, Zhejiang, China 325035.
authors.forename: Huili
authors.initials: H
authors.lastname: Wang
authors.forename: Ailian
authors.initials: A
authors.lastname: Duan
authors.forename: Jingwen
authors.initials: J
authors.lastname: Mao
authors.forename: Baoguang
authors.initials: B
authors.lastname: Che
authors.forename: Wenwei
authors.initials: W
authors.lastname: Wang
authors.forename: Meiping
authors.initials: M
authors.lastname: Ma
authors.forename: Xuedong
authors.initials: X
authors.lastname: Wang
mesh_terms: D004958:Estradiol / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013696:Temperature
chemical_list: D052578:Ionic Liquids; D004958:Estradiol