Communication. Water-soluble copolymers: a new class of media for fluorescence and phosphorescence analyses in aqueous systems?

Abstract

The first observations of room temperature stabilized phosphorescence (RTSP) from analytes solubilized in aqueous media by a water-soluble copolymer are reported. Pyrene and benzophenone were dispersed in the hydrophobic domains created within the coils of a copolymer of 1-vinylnaphthalene and methacrylic acid, containing 36 mol-% of 1-vinylnaphthalene. The hydrophobic cavities allow sufficient interactions with heavy ions, such as Tl⁺, dissolved in the aqueous phase, to produce effective population of the triplet states of the sequestered analytes. In addition, the cavities are sufficiently protective to the excited states of the occluded guest molecules that room temperature phosphorescence can be generated readily with simple nitrogen purging. In terms of convenience of sample preparation, water-soluble copolymers offer distinct advantages over alternative media, such as doped micelles, for the creation of RTSP. These preliminary studies point the way towards the ‘custom design’ of copolymers for specific analytical applications involving aromatic hydrocarbon analytes in aqueous media.