Improved catalytic photometric determination of iron(III) in cetylpyridinium premicellar aggregates

Alexiev, A. A.; Rubio, Soledad; Deyanova, M.; Stoyanova, A.; Sicilia, María Dolores; Bendito, D. Pérez

doi:10.1016/0003-2670(94)80353-6

Cited by 10 publications

(5 citation statements)

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“…Premicellar aggregates are thought to exist when C 16 TAB concentration is lower than 7.4 mM, while stable micelles are observed at higher concentrations of the lipid surfactant . It has been previously suggested that smaller, premicellar aggregates can facilitate enhanced catalytic activity of Fe(III) and promote oxidation of sulfanilic acid compared to fully matured micelles, likely due to the increased ratio of the reactant species to the surfactant molecules . We therefore hypothesized that increasing the ratio of the metallic species (Au + ) to the aggregate (premicellar/micellar) C 16 TAB species will lead to greater propensity for nanoparticle formation upon exposure to ionizing radiation and therefore increased sensitivity of the resulting nanosensor at lower radiation doses.…”

Section: Resultsmentioning

confidence: 98%

“…34 It has been previously suggested that smaller, premicellar aggregates can facilitate enhanced catalytic activity of Fe(III) and promote oxidation of sulfanilic acid compared to fully matured micelles, likely due to the increased ratio of the reactant species to the surfactant molecules. 35 We therefore hypothesized that increasing the ratio of the metallic species (Au þ ) to the aggregate (premicellar/micellar) C 16 TAB species will lead to greater propensity for nanoparticle formation upon exposure to ionizing radiation and therefore increased sensitivity of the resulting nanosensor at lower radiation doses. On the basis of the assumption that the number of aggregate species increases with lipid concentration, 34 we next investigated different concentrations of C 16 TAB (0.7, 2, 4, and 10 mM) in the nanosensor, while keeping the concentrations of gold ions and ascorbic acid constant.…”

Section: Resultsmentioning

confidence: 99%

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A Colorimetric Plasmonic Nanosensor for Dosimetry of Therapeutic Levels of Ionizing Radiation

et al. 2015

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Modern radiation therapy using highly automated linear accelerators is a complex process that maximizes doses to tumors and minimizes incident dose to normal tissues. Dosimeters can help determine the radiation dose delivered to target diseased tissue while minimizing damage to surrounding healthy tissue. However, existing dosimeters can be complex to fabricate, expensive, and cumbersome to operate. Here, we demonstrate studies of a liquid phase, visually evaluated plasmonic nanosensor that detects radiation doses commonly employed in fractionated radiotherapy (1-10 Gy) for tumor ablation. We accomplished this by employing ionizing radiation, in concert with templating lipid surfactant micelles, in order to convert colorless salt solutions of univalent gold ions (Au(1)) to maroon-colored dispersions of plasmonic gold nanoparticles. Differences in color intensities of nanoparticle dispersions were employed as quantitative indicators of the radiation dose. The nanoparticles thus formed were characterized using UV-vis absorbance spectroscopy, dynamic light scattering, and transmission electron microscopy. The role of lipid surfactants on nanoparticle formation was investigated by varying the chain lengths while maintaining the same headgroup and counterion; the effect of surfactant concentration on detection efficacy was also investigated. The plasmonic nanosensor was able to detect doses as low as 0.5 Gy and demonstrated a linear detection range of 0.5-2 Gy or 5-37 Gy depending on the concentration of the lipid surfactant employed. The plasmonic nanosensor was also able to detect radiation levels in anthropomorphic prostate phantoms when administered together with endorectal balloons, indicating its potential utility as a dosimeter in fractionated radiotherapy for prostate cancer. Taken together, our results indicate that this simple visible nanosensor has strong potential to be used as a dosimeter for validating delivered radiation doses in fractionated radiotherapies in a variety of clinical settings.

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

A Colorimetric Plasmonic Nanosensor for Dosimetry of Therapeutic Levels of Ionizing Radiation

et al. 2015

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“…It means that there would be no Fe 2+ accumulation in the solution if Fenton reactions occurred. The concentration of Fe 2+ was measured along with the photodegradation process with o -phen method , and the results (Figure ) have excluded the occurrence of Fenton reactions. Combining the results in Figure we can see that the speed of the photodegradation of dyes slowed down corresponding to the increasing of Fe 2+ , i.e., the decreasing of Fe 3+ ions, which suggested that Fe 2+ was not able to accelerate the photodegradation.…”

Section: Resultsmentioning

confidence: 99%

A New Role for Fe³⁺ in TiO₂ Hydrosol: Accelerated Photodegradation of Dyes under Visible Light

Wang

Liu

Cai

2008

Environ. Sci. Technol.

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The effect of Fe3+ on the photocatalytic activity of TiO2 hydrosol prepared through a low-temperature route has been investigated under visible light irradiation. The total reactive oxygen species (ROS) level and the accumulation of Fe2+ during the photodegradation process were detected to examine the role of Fe3+. In contrastto an aqueous TiO2 dispersion where Fe3+ strongly inhibited the photoactivity of TiO2 via suppressing the reduction of O2 and decreasing the production of ROS, Fe3+ accelerated the photodegradation of all dyes examined in the hydrosol through increasing the yield of oxidative ROS. The influence of the prebound hydroxyl groups on the surface of TiO2 was compared to that of free alcohols in aqueous solution, which revealed the cooperative function of the surface hydroxyl groups. The thoroughly contrary effect of Fe3+ on the photocatalysis of TiO2 hydrosol and TiO2 powder, which are all anatase nanocrystallites but are synthesized with different procedures, was ascribed to the complexation of the hydroxyl groups bound to TiO2 surface with Fe3+. The formation of such complexes has resulted in an altered electron-transfer pathway of the dye-sensitized photocatalysis under visible light irradiation.

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“…17,18 Various kinetic methods based on the catalytic action of iron on the oxidation of organic compounds have been reported in several reviews [19][20][21] and original papers. 13,[22][23][24][25] Among the many sensitive techniques for iron determination, kinetic catalytic methods are worth special mention on account of their high sensitivity and simple and low-cost equipment. 26 Developing of novel simple kinetic procedures, carried out at an easily maintained temperature for a short reaction time, is still needed from the practical point of view.…”

Section: Introductionmentioning

confidence: 99%

Spectrophotometric Determination of Trace Iron by Using Its Catalytic Effect on the N-Phenylanthranilic Acid-Potassium Periodate Reaction

Stoyanova

2008

ANAL. SCI.

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The analytical features of the reaction between N-phenylanthranilic acid (PAA) and potassium periodate in acidic medium are explored with the aim of improving the catalytic kinetic determination of iron in water samples. In the presence of Fe(II, III), PAA is oxidized by potassium periodate in a formic acid medium to form a violet-colored compound. The reaction is followed spectrophotometrically by measuring the increase in the absorbance of the oxidation product at 525 nm. The variables that affected the reaction rate were investigated and the reaction conditions were established. Calibration graphs are linear in the range of concentrations 2 -500 ng mL -1 . As low as 10 -8 mol L -1 Fe(II, III) can be easily determined by the fixed time method. The established catalytic method was successfully applied to the determination of iron in tap water and in pharmaceutical samples.

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Improved catalytic photometric determination of iron(III) in cetylpyridinium premicellar aggregates

Cited by 10 publications

References 11 publications

A Colorimetric Plasmonic Nanosensor for Dosimetry of Therapeutic Levels of Ionizing Radiation

A Colorimetric Plasmonic Nanosensor for Dosimetry of Therapeutic Levels of Ionizing Radiation

A New Role for Fe³⁺ in TiO₂ Hydrosol: Accelerated Photodegradation of Dyes under Visible Light

Spectrophotometric Determination of Trace Iron by Using Its Catalytic Effect on the N-Phenylanthranilic Acid-Potassium Periodate Reaction

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Improved catalytic photometric determination of iron(III) in cetylpyridinium premicellar aggregates

Cited by 10 publications

References 11 publications

A Colorimetric Plasmonic Nanosensor for Dosimetry of Therapeutic Levels of Ionizing Radiation

A Colorimetric Plasmonic Nanosensor for Dosimetry of Therapeutic Levels of Ionizing Radiation

A New Role for Fe3+ in TiO2 Hydrosol: Accelerated Photodegradation of Dyes under Visible Light

Spectrophotometric Determination of Trace Iron by Using Its Catalytic Effect on the N-Phenylanthranilic Acid-Potassium Periodate Reaction

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A New Role for Fe³⁺ in TiO₂ Hydrosol: Accelerated Photodegradation of Dyes under Visible Light