A highly fluorescent hydrophilic ionic liquid as a potential probe for the sensing of biomacromolecules.
With respect to the conventional imidazolium ionic liquids which generally create very weak fluorescence with quantum yields at extremely low levels of 0.005-0.02, a symmetrical hydrophilic ionic liquid 1,3-butylimidazolium chloride (BBimCl) was found to be highly fluorescent with λ(em) at 388 nm when excited at λ(ex) < 340 nm. The very high quantum yield of BBimCl in aqueous medium, derived to be 0.523 when excited at 315 nm, was attributed to its symmetrical plane conjugating structure. In the presence of hemoglobin, the fluorescence of BBimCl could be significantly quenched, resulting from the coordinating interaction between the iron atom in the heme group of hemoglobin and the cationic imidazolium moiety. This feature of the present hydrophilic ionic liquid makes it a promising fluorescence probe candidate for the sensitive sensing of hemoglobin. A linear regression was observed within 3 × 10(-7) to 5 × 10(-6) mol L(-1) for hemoglobin, and a detection limit of 7.3 × 10(-8) mol L(-1) was derived.
Research Center for Analytical Sciences, Northeastern University, Box 332, Shenyang 110819, China.
Xu-Wei
XW
Chen
Jia-Wei
JW
Liu
Jian-Hua
JH
Wang
D005456:Fluorescent Dyes / Q000737:chemistry*; D006454:Hemoglobins / Q000032:analysis* / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D007093:Imidazoles / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D011789:Quantum Theory; D013050:Spectrometry, Fluorescence
D005456:Fluorescent Dyes; D006454:Hemoglobins; D007093:Imidazoles; D052578:Ionic Liquids