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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. Results for the dehalogenation of the iodinated compounds, o-iodobenzoic acid and L-thyroxine (3,5,3',5'-tetraiodothyronine) sodium, were compared with a standard inorganic iodide solution. After establishing the optimum chemical and instrumental conditions, detection limits of 0.8 x [10.sup.-9] and 0.2 x [10.sup.-9] M and linear calibration graphs were obtained with dynamic ranges from 0.79 x [10.sup.-7] to 7.9 x [10.sup.-7] M and from 0.20 x [10.sup.-7] to 2.0 x [10.sup.-7] M for o-iodobenzoic acid and L-thyroxine, respectively. A precision of ~4% relative standard deviation (n = 6) was provided at an o-iodobenzoic acid concentration of 0.79 x [10.sup.-7] M. The method developed was applied to the on-line determinations of iodinated aromatic compounds such as L-thyroxine sodium and iopamidol ((S)-N,N'-bis[2-hydroxy-1-(hydroxymethyl)ethyl]-5- [(2-hydroxy-1-oxopropyl)amino]-2,4,6-triiodoisophthaldiamide) in pharmaceuticals.

A fast and sensitive method for the determination of atropine, an alkaloid closely related to cocaine, is proposed. The principles of on-line ion-pair formation of alkaloid-metal complexes and liquid-liquid extraction are applied to the chemiluminescence determination of atropine. On mixing with a reversed micellar medium of cetyltrimethylammonium chloride in dichloromethanecy-clohexane (1:1 v/v)-water (0.3 M Na(sub 2)CO(sub 3)) containing luminol, the ion-pair complex of tetrachloroaurate(III) with atropinium produced an analytical chemiluminescence signal when it entered the reversed micellar water pool. Using the reverse-flow injection and chemical conditions optimized for atropine in aqueous samples, a detection limit of 1 ng/mL was achieved and a linear calibration graph was obtained with a wide dynamic range from 10 ng/mL to 100 (mu)g/mL. The proposed method is simple and provides a good precision with a relative standard deviation (n = 6) of ca. 3% at the atropine concentration of 100 ng/mL. After a preliminary study involving the potential interference from species of organic, inorganic, and metallic nature, the method was applied to the determination of atropine in artificial urine samples and of atropine and scopolamine in pharmaceutical formulations.

A new method, based on the direct combination of solvent extraction with luminol chemiluminescence (CL) in a reversed micellar system of cetyltrimethylammonium chlorlde--water (buffered with sodium carbonate)--6:5 (v/v) chloroformcyclohexane, is established for the determination of gold in aqueous solutions. The interference behavior of 15 metals on the reference gold CL signals was evaluated. By dispersing an aqueous solution of the Individual Interferent alone and in admixture with the analyte, a comparative inquiry on their CL behavior was also carried out in the reversed micellar medium. Separation of analyte from interferents by extraction with trin-octylphosphine oxide in chloroform resulted in reduced or no interference. The present method was applled to the determination of gold in industrial samples of sllver-based alloy., A method for discovering gold in the presence of various potential metal ion interferants at different chemiluminescence reaction levels with luminol in reverse micelles is discussed. Tri-n-octylophospine oxide was used to extract into chloroform the interfering agents from silver-based alloys which were selectively characterized by reversed micellar mediated chemiluminescence. The potential ofthe method for gold determination was demonstrated.