Fluorescence enhancement of imidazolium ionic liquid by its confinement on PVC for in situ selective quantification of hemoglobin

ACS Appl Mater Interfaces. 2013 Nov 27;5(22):12156-62. doi: 10.1021/am404069f. Epub 2013 Nov 12.

Abstract

A hydrophilic ionic liquid (methylimidazolium chloride, NmimCl)-polyvinyl chloride ionomer (NmimCl-PVC) was prepared by immobilizing and confining N-methylimidazole onto PVC chains. The NmimCl-PVC ionomer exhibits a 4-fold enhancement on the fluorescence intensity with respect to that of NmimCl, attributing to the confinement of ionic liquid by the PVC chain. The fluorescence is excitation-dependent with a maximum at λem 430 nm when excited at 325 nm. In addition, the fluorescence intensity of NmimCl-PVC ionomer increases remarkably with the loading ratio of N-methylimidazole in the range of 4.3-15.1%. The fluorescence quantum yield and lifetime were derived to be 0.112/7.1 ns for the NmimCl-PVC ionomer and 0.063/8.8 ns for NmimCl. Furthermore, hemoglobin is selectively adsorbed by NmimCl-PVC and causes significant fluorescence quenching of the ionomer via dynamic quenching and energy transfer between NmimCl-PVC and hemoglobin. A solid surface fluorimetric procedure was developed for surface adsorption and preconcentration of hemoglobin followed by in situ detection. A linear dynamic range of 0.3-26.2 μg mg(-1) is achieved with a detection limit of 0.1 μg mg(-1). Regarding hemoglobin in aqueous solution, the linear range 5-300 μg mL(-1) is achieved along with a detection limit of 2 μg mL(-1).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cattle
  • Hemoglobins / analysis*
  • Humans
  • Imidazoles / chemistry*
  • Ionic Liquids / chemistry*
  • Polyvinyl Chloride / chemistry*
  • Spectrometry, Fluorescence / methods

Substances

  • Hemoglobins
  • Imidazoles
  • Ionic Liquids
  • imidazole
  • Polyvinyl Chloride