Photocatalytic dehalogenation coupled on-line to a reversed micellar-mediated chemiluminescence detection system: application to the determination of iodinated aromatic compounds.

The effects of illumination time, temperature, catalyst concentration, and pH on the on-line photocatalytic dehalogenation of iodinated aromatic compounds in a near-UV-illuminated titanium dioxide (anatase type) aqueous suspension were monitored via the iodine-luminol chemiluminescence (CL) reaction in a reversed micellar medium, and a new, automated, rapid, and efficient method was developed. A water-cooled, 400-W high-pressure Hg lamp was used as an internal light source. The flow procedure involved the following: (1) photocatalytic dehalogenation/degradation of the iodinated compound by the near-UV-illuminated titanium dioxide and the production of iodide species, (2) oxidation of iodide into iodine, (3) extraction of iodine into cyclohexane, (4) membrane separation of the iodine-containing organic phase from the aqueous phase, and (5) the detection of iodine using the luminol CL reaction in the reversed micellar solution of cetyltrimethylammonium chloride in 6:5 (v/v) chloroform-cyclohexane/water buffered with sodium carbonate.