Effect of Oxovanadium(IV) Acetylacetonate on the Chemiluminescence Reaction of Luminol in Reverse Micelles.

Abstract

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...

Reversed Micellar Mediated Luminol Chemiluminescence Detection of Iron(II, III) Combined with On-Line Solvent Extraction Using 8-Quinolinol

“…Visible absorption measurements showed that increasing the concentration of sodium hydroxide in the reversed micellar solution caused a decrease in the absorbance of the complex, indicating decomposition of the complex, in which attack of nucleophilic hydroxide ion to the central metal of the complex may play an essential role at the surfactant-water pool interface of the CTAC reverse micelle; the free iron(III) ion produced is considered to be available for the CL catalysis. In our previous work 11 , a similar behavior of the oxovanadium(IV) acetylacetonate complex in the RMM-CL reaction was observed; it has been pointed out that the free VO 2 + ion produced transiently from decomposition of the complex upon its uptake by the reverse micelles may play an important part in the RMM-CL process.…”

“…[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.…”

“…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.…”

Reversed Micellar-Mediated Luminol Chemiluminescence Reaction with Bis(acetylacetonato)oxovanadium(IV)

“…The FI system reported in our previous paper 14 has been used to carry out the flow CL measurements: the multicomponent instrument was composed of a Hitachi (Tokyo) Model K-1000 flow injection analyzer, equipped with a 16-port rotary, programmed automatic injection valve, a Tosoh (Tokyo) Model CCPM computer-controlled pump unit, and a Niti-on (Funahashi) Model LF-800 photometer with a coiled 70-mm 3 The solutions of sample and reversed micellar luminescence reagent were sucked into their respective loops of 100 mm 3 , then simultaneously inserted into the carrier streams of chloroform using the automatic rotary injection valve. The carrier flow rates of 2 cm 3 min -1 were used to drive both the sample and reagent streams through the FI system, as reported previously.…”

“…The carrier flow rates of 2 cm 3 min -1 were used to drive both the sample and reagent streams through the FI system, as reported previously. 14 The intensity of CL emission was taken as the difference in the observed peak heights for the analyte and the blank, although the blank CL emission by luminol alone in the reversed micellar solution was very faint.…”