Higashi-Upon mixing of oxovanadium(IV) acetylacetonate, this complex caused an increase in the chemiluminescence (CL) of luminol in a reverse micellar medium of cetyltrimethylammonium chloride in chloroform-cyclohexane (6:5 vlv)-water (buffered with NaOH-Na2C03, pH 12.5) even in the absence of an oxidizing reagent such as hydrogen peroxide. In this CL process, the reaction of Luminol with the oxovanadium(IV) ion produced from the decomposition of the oxovanadium(IV) complex in the reverse micelles is probably significant. A flow-injection method for the oxovanadium(IV) determination based on the present reversed micellar mediated CL reaction was examined. All the analytical conditions were optimized using the sample solution of oxovanadium(IV) acetylacetonate in chloroform. A detection limit (DL) of 0.1 ng cm"3 and a linear calibration graph was obtained with a dynamic range from the DL to 50 ng cm"3. KeywordsChemiluminescence, luminol, oxovanadium(1V) acetylacetonate, reverse micelles, cetyltrimethylammonium chlorideMany of the various unique properties of reversed micelles used as a medium for chemiluminescence (CL) can be brought to bear upon CL reaction systems in order to improve their analytical performance; "2 the CL systems based on use of luminol as the CL reagent seem to have benefited the most from the presence of reversed micellar media in spectroscopic method. When an aqueous solution of the luminescent reagent is dispersed in the bulk organic phase containing surfactant molecules, a macroscopically homogeneous solution of reverse micelles is produced. The structure of the reverse micelles is such that the center of the micellar core is filled with water surrounded by surfactant polar heads, while the hydrophobic chains are directed into the bulk non-polar organic phase; the inner water pool provides a unique and versatile reaction field, referred to as a microreactor.3 It is believed that the CL reaction occurs at the surfactantwater pool interface of the reverse micelles dispersed in the bulk organic solvent. "4 Besides other advantages, enhanced sensitivity can be achieved when reverse micelles are incorporated in the CL analysis.4's We have investigated a CL emission from metalcatalyzed oxidation of Luminol in reverse micelles and its analytical application.6"1In our previous studies, a reversed micellar medium of the surfactant, cetyltrimethylammonium chloride (CTAC) was used for the luminol CL reaction in order to combine a reversed micellar mediated CL (RMM-CL) detection system with a solvent extraction technique.6"12 The extract can be mixed directly with the reversed micellar solution of luminol dispersed in oil. We examined development of a hybrid method for the determinations of iron(III),6 iodin&2 and gold(III)7"10 and rhodium(III)," and proposed an online procedure of solvent extraction combined with RMM-CL detection using a membrane filter for phase saparation.10In the presence of hydrogen peroxide, an enhancement in the CL emission resulting from the luminol reaction in reversed micel...

A reverse micelle is a droplet of water surrounded by surfactant molecules dispersed in an organic solvent of low polarity, where their polar groups are concentrated in the inner aqueous core of the aggregate, while their hydrophobic moieties extend into the bulk organic solvent. The water pool, formed by water molecules included in the core of reverse micelles, provides a unique and versatile reaction field, referred to as microreactors.1-4 The area with the most applications of reversed micellar media in spectroscopy is perhaps that of analytical bioluminescence or chemiluminescence (CL) measurements.3,4 It has been pointed out that the CL reaction occurs at the surfactant-water pool interface of the reverse micelles dispersed in the bulk organic solvent.3,5 Although a CL emission from luminol oxidation catalyzed by metal ions and metalcontaining ions is well known in conventional or usual aqueous solution 6,7 , in reversed micellar solutions this is rarely reported. [8][9][10][11] In our previous work 8 it was observed that the uptake of the iron(III) complex of 8-quinolinol (oxine), Fe(oxine) 3 , by a reverse micelle of cetyltrimethylammonium chloride (CTAC) into the water pool and its subsequent conversion into a reactive species, that is, iron(III) ion capable of catalyzing the CL reaction of luminol with hydrogen peroxide occur.Accomplished in many ways, the extraction of metal ions with a suitable organic solvent is effective in separation, and can be used in both micro and macro levels of concentration. When usual aqueous solutions are used in CL measurements after extraction, however, a relatively time-consuming procedure, like back extraction into an aqueous solution or evaporation of the solvent, is certainly needed before CL detection. 12On the other hand, the extract can be mixed directly with a reversed micellar solution of luminol dispersed in oil. We thus examined the development of a hybrid method based on the combination of the reversed micellar-mediated CL (RMM-CL) detection with solvent extraction for the determinations of iodine 13 , gold(III) 14,15 , and rhodium(III). 10 Furthermore, an online procedure for extraction via ion-pair formation followed by the RMM-CL detection was proposed for gold(III) determination using a reverse-flow injection (FI) system with a membrane filter for phase separation. 16 In this work, the luminol CL enhanced by the Fe(oxine) 3 complex in reverse micelles was investigated and on-line extraction through complex formation was combined with the RMM-CL reaction An enhancement of the chemiluminescence (CL) emission, observed when the iron(III) complex of 8-quinolinol (oxine), Fe(oxine)3, was mixed with a reversed micellar solution of cetyltrimethylammonium chloride in chloroform-cyclohexane (6:5 v/v)-water (1.0 M NaOH) containing luminol and hydrogen peroxide, was investigated in order to develop a method for iron(III) determination based on the direct coupling of on-line solvent extraction with a reversed micellar-mediated CL reaction in a reverse-flow injection ...

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Milk lipids were separated using a hexane:isopropanol mixture; then they were fractionated into apolar, medium polar and polar portions by SPE using a LC-Si column. The apolar fraction was further separated into 4 more portions depending on their polarity by another SPE method using a Florosil column. Levels of Cl, Br and I were measured by NAA. Halogens were detected in all separated fractions; but their highest levels were found in the most apolar fraction containing hydrocarbons which strongly indicates the presence of anthropogenic organohalogen compounds in milk. In addition, iodide and iodate ions in whole milk samples were measured.