Photocatalytic Dehalogenation Coupled On-Line to a Reversed Micellar-Mediated Chemiluminescence Detection System:  Application to the Determination of Iodinated Aromatic Compounds

Fujiwara, Terufumi; Mohammadzai, Imdad Ullah; Inoue, Hidekazu; Shimizu, Yasuhide; Kumamaru, Takahiro

doi:10.1021/ac030004x

Cited by 7 publications

(6 citation statements)

References 40 publications

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“…3 Furthermore, an FI method based on the on-line photocatalytic dehalogenation combined with the solvent extraction/RMM-CL detection has been developed and was applied successfully for the determination of iodinated aromatic compounds such as Lthyroxine sodium and iopamidol in pharmaceuticals. 10 The reported method for the RMM-CL determination of iodine is very sensitive and selective, and yet it is dependent on the use of chloroform as a component of the reversed micellar bulk organic solvent, 2,3,10 thus making it environmentally less good. In fact, it is the solubility of the surfactant that dictates the choice of the bulk organic solvent: The surfactant CTAC is sparingly soluble in inert aliphatic hydrocarbons 11 but is soluble in chlorinated aliphatic hydrocarbons e.g., chloroform and dichloromethane.…”

Section: Introductionmentioning

confidence: 99%

“…In fact, it is the solubility of the surfactant that dictates the choice of the bulk organic solvent: The surfactant CTAC is sparingly soluble in inert aliphatic hydrocarbons 11 but is soluble in chlorinated aliphatic hydrocarbons e.g., chloroform and dichloromethane. In our reported research, mixtures of 6 + 5 (v/v) chloroform-cyclohexane 2,3,10,[12][13][14][15][16] and 1 + 1 (v/v) dichloromethane-cyclohexane 17 have been used as the bulk solvent systems. These have the capability to give a stable, optically transparent, and homogenous solution of CTAC in the presence of co-solubilized water and other reagents.…”

Section: Introductionmentioning

confidence: 99%

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An Improved Method for the Flow-Injection Determination of Iodine Using the Luminol Chemiluminescence Reaction in a Reversed Micellar Medium of Cetyltrimethylammonium Chloride in 1-Hexanol-Cyclohexane

et al. 2006

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Amphiphilic molecules (surfactants) when dissolved in a bulk organic non-polar solvent form organized assemblies called reverse micelles when an appropriate concentration of surfactants, the critical micellar concentration, is reached. 1 The structure of a reverse micelle is the inverse prototype of the normal micellar structure. The polar head groups of the surfactant molecules are in contact with the tiny water pool (containing the associated counter ions) in the core of the reverse micelle while the hydrophobic chains are directed outward into the bulk organic solvent. In our previous work, chemiluminescence (CL) generation was observed upon mixing iodine with luminol dispersed in the carbonate-buffered water pool of the reversed micelle of cetyltrimethylammonium chloride (CTAC). 2 Absorption measurements demonstrated that, on mixing of the cyclohexane solution of iodine with the CTAC reversed micellar solution, iodine could be transferred instantly and completely from the organic phase into the buffered water pool of the reverse micelle.2 On the other hand, when iodine was premixed with the reversed micellar solution containing the carbonate buffer alone and then the resulting mixture was mixed with the reversed micellar solution of luminol, no CL emission was produced. 3 In the CL reaction of luminol with iodine, hypoiodous acid and the iodite ion have been proposed as oxidants in usual alkaline aqueous solutions. 4 Thus, a possible explanation would be that, on iodine uptake by the reverse micelle, these oxidizing agents may be produced initially and be present transiently at the surfactant-water pool interface, before reacting immediately with luminol anion to generate luminescence. 2,3 The chloride ion, the counter ion of CTAC, is also presumed to be available mostly at the surfactant-water pool interface, 5 and to cause its association with iodine. 6 This might facilitate the quantitative uptake of iodine by the CTAC reverse micelle. In addition, the concentration effect of iodine can be achieved by entrance of iodine into a small volume of the interfacial region in the CTAC reverse micelles, where acceleration of the luminol CL reaction seems likely due to more efficient association of luminol with the generated oxidants, resulting in the generation of more intense or higher CL signals.Several metal ions present in aqueous samples may interfere with iodine determination by using the usual aqueous phase luminol CL reaction; thus, their removal is needed by incorporating separation science techniques into the procedure. 7 When iodide is oxidized into iodine, since iodide is not CLactive, subsequent separation from the oxidant used which could interfere with the CL determination is also required. 2,3,8 One of the effective methods of preconcentration and separation of iodine from such interferents as oxidant and metallic species is its extraction with a suitable organic solvent. Yasuda Women's College, Yasuhigashi, Japan To eliminate the use of chlorinated hydrocarbons, we have improved the method for...

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An Improved Method for the Flow-Injection Determination of Iodine Using the Luminol Chemiluminescence Reaction in a Reversed Micellar Medium of Cetyltrimethylammonium Chloride in 1-Hexanol-Cyclohexane

et al. 2006

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“…Also an on-line solvent extraction technique was combined with the reversed micellar-mediated CL detection. [20][21][22][23] There are several reports concerning the application of reversed micellar media as mobile phases in liquid chromatography, 24,25 TLC, 26,27 and SFC; 28 certain problems related to the adsorption of the surfactants were also reported. 25 The adsorption of cationic surfactants at solid/liquid interface is dependent on the nature of substrate and conditions of the medium, e.g., concentration of the surfactant, pH, ionic strength, and electrostatic as well as hydrophobic interactions are significant in it.…”

Section: Introductionmentioning

confidence: 99%

Adsorption Behavior of the Cetyltrimethylammonium Chloride Reverse Micelles on Porous Silica Gels

et al. 2009

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The adsorption behavior of reverse micelles of cetyltrimethylammonium chloride (CTAC) onto porous silica gels of various pore sizes has been investigated. A decrease in the amount of CTAC in the reversed micellar bulk solution in chloroform/water added to the silica gel in a column was observed, indicating the CTAC adsorption onto the silica surface. The adsorption profile obtained showed a maximum of the adsorbed surfactant amount, where the point of surface saturation may be reached, beyond which the adsorption amount remained unchanged. The adsorption of CTAC was also dependent on the specific surface area of the silica gel used. These results suggest that a CTAC monolayer may be formed and completed on the silica surface. The adsorbed CTAC amount slightly decreased with increasing the water to surfactant molar ratio, R, in the reversed micellar bulk solution, although at R < 2 the CTAC adsorption remained constant with silica gels having larger pore diameters. Even in the presence of traces of water moisture in the bulk solution used for the CTAC adsorption, the adsorption of water on silica gel was also observed and the molar ratios, RG, of the water to surfactant adsorbed on different silica gels were almost unity, implying that the silica gel may tend to hold some of water molecules originally adsorbed on its surface. The adsorption of CTAC molecules appears to occur through the adsorbed water molecules, probably polarized at the silica surface, and a CTAC-water-silica nanointerface seems to be formed. The adsorbed water amount or RG also increased with an increase in R and on silica gels with larger pore diameters and a plateau was observed in the R range of 3 -4, beyond which an increase in RG occurred again. The water molecules present in the vicinity of the adsorbed CTAC and the silica surface may possess different properties at different R and RG values.

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“…There are several conventional methods to detect AFP and T 4 , such as RIA [3,4], ELISA [5,6], luminescence [7,8], and chemiluminescence assay [9,10]. Although both RIA and ELISA have advantages of high sensitivity, they are time consuming and the operations require a well-trained technician and special equipment in a laboratory [11].…”

Section: Introductionmentioning

confidence: 99%

Capillary electrophoresis enzyme immunoassay for alpha‐fetoprotein and thyroxine in human serum with electrochemical detection

Zhang

2008

J of Separation Science

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A novel CE-based enzyme immunoassay (CE-EIA) method was developed in o-aminophenol (OAP)-H(2)O(2)-horseradish peroxidase (HRP) system and applied to benign liver disease and hyperthyroidism research in the clinical practical field. In the presented method, after the enzyme immunoreaction, the HRP-labeled antibody or HRP-labeled antigen catalyzed the enzyme substrate OAP and H(2)O(2). The product of the enzymatic catalysis reaction 2-aminophenoxazine-3-one (AP) was determined using electrochemical detection on a Pt electrode at the outlet of the reaction capillary. Factors influencing the performance, including running buffer concentration, separation, and detection voltage, were investigated to the optimum conditions. Noncompetitive and competitive models were utilized to detect alpha-fetoprotein (AFP) and thyroxine (T(4)) in human sera, respectively. The linear ranges and the detection limits (S/N = 3) were from 1.5 to 66.6 ng/mL and 0.48 ng/mL for AFP, and from 1.7 to 260.0 ng/mL and 1.0 ng/mL for T(4). The results of this method were linear proportional to those of spectrophotometric ELISA method, giving a good prospect for a new clinical diagnostic instrument.

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Photocatalytic Dehalogenation Coupled On-Line to a Reversed Micellar-Mediated Chemiluminescence Detection System: Application to the Determination of Iodinated Aromatic Compounds

Cited by 7 publications

References 40 publications

An Improved Method for the Flow-Injection Determination of Iodine Using the Luminol Chemiluminescence Reaction in a Reversed Micellar Medium of Cetyltrimethylammonium Chloride in 1-Hexanol-Cyclohexane

An Improved Method for the Flow-Injection Determination of Iodine Using the Luminol Chemiluminescence Reaction in a Reversed Micellar Medium of Cetyltrimethylammonium Chloride in 1-Hexanol-Cyclohexane

Adsorption Behavior of the Cetyltrimethylammonium Chloride Reverse Micelles on Porous Silica Gels

Capillary electrophoresis enzyme immunoassay for alpha‐fetoprotein and thyroxine in human serum with electrochemical detection

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