Surfactants which form micelles and cyclodextrins are two of the most common forms of organized media. Surfactants are known for their ability to self-assemble in water and/or organic solvents and form normal/reverse micelles above the critical micelle concentration (CMC). Micellar solubilization in surfactant solutions has been widely exploited in analytical chemistry. The formation of inclusion compounds, by using cyclodextrins as hosts, has been also frequently used to enhance the analytical responses of analytes by incorporation of guest molecules into the cyclodextrins hydrophobic cavity [1].The first observation of room temperature phosphorescence (RTP), using a microscopically organized media, used sodium dodecylsulfate (SDS) micelles in the presence of tallium [2]. Since then, several media have been investigated to stabilize the triplet-state in fluid solution at room temperature. Normal micelles, mainly sodium dodecylsulfate [3][4][5][6], cetyltrimethylammonium bromide (CTB) [7][8][9] and Triton X-100 [10] micelles, have been used in RTP analytical applications. As an alternative to the use of normal micelles, microemulsions, formed in heptane-SDS-1-pentanol, have been also reported for RTP obtention [11][12][13][14].Cyclodextrins (CDs) can form complexes with phosphors and heavy atom containing additives and these host-guest aggregates serve to populate and stabilize the fragile tripletstate, producing characteristic room temperature phosphorescence. These inclusion complexes induce an intense phosphorescence emission which is partially insensitive to Cyclodextrins are composed of D-glucose residues joined by α(1→4) linkages. α-, β-and γ-CDs, which are made up of six, seven and eight D-glucose residues, are the most common members of a CD family. These CDs are shaped like a truncated cone with a hollow, hydrophobic cavity in which a hydrophobic guest can be incorporated.Molecular encapsulation by means of molecular inclusion complex formation offers a new approach in analytical chemistry. Generally, the inclusion complex involves the spatial entrapment of a single guest molecule in the cavity of the host molecule, without the formation of any covalent bonds. Cyclodextrins, cyclic non-reducing oligosaccharides, have been extensively used to obtain these inclusion complexes. In particular, many studies have focused on the ability of CDs to include guests of varying sizes in different stoichiometric ratios and several analytical applications of these complexes have been reported [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30].It is well documented that, depending upon the host CD (i.e. α-, β-or γ-CD) and the size of the guest, different

The inclusion complex of benzo[ a]-12H-phenothiazine (BPHT) and 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) was investigated in an aqueous solution containing 1% ethanol. It was found that the fluorescence emission intensity of the complexed fluorophore is six times larger than that of un complexed species and 1.5 times higher than that in pure ethanol. BPHT forms a 1:1 complex when included in the HP-β-CD. An association constant of the complex of 100±20 M−1 was calculated by using the Benesi–Hildebrand treatment of fluorescence emission data. A discussion based on AM1 semiempirical calculation of BPHT geometry indicates that the inclusion of BPHT in HP-β-CD is partially achieved, probably by the hydrophobic aromatic moiety of the molecule.

Abstract. UV irradiation of four non-fluorescent phenylurea herbicides including linuron, diuron, isoproturon and neburon is shown to yield fluorescent photoproducts. The photochemically-induced fluorescence (PIF) properties of these herbicides in several media (water, 2-propanol and their mixtures) and aqueous micellar solutions of sodium dodecyl sulfate (SDS), and cetyltrimethylammonium chloride (CTAC) are reported. The use of micellar media enhances significantly the PIF signal relative to an aqueous solution. A PIF method is developed for the determination of the four herbicides under study, with linear dynamic ranges over about one order of magnitude, and limits of detection (LOD) between 410 and 640 ng mL -1 , according to the compound. Applications to the analysis of tap water and river water samples yield satisfactory recoveries (86-115 %).