Effect of Selected Organic Solvents on Hydroxyl Radical-Dependent Light Emission in the Fe<sup>2+</sup>-EGTA-H<sub>2</sub>O<sub>2</sub> System

Numerous compounds that are scavengers of hydroxyl radicals (•OH) in Fenton systems have low solubility in water. Therefore, they are dissolved in organic solvents to reach suitable concentrations in the reaction milieu of the Fenton system. However, these solvents may react with •OH and iron, leadi...

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Main Authors: Krzysztof Sasak, Michał Nowak, Anna Wlodarczyk, Agata Sarniak, Dariusz Nowak
Format: Article
Language:English
Published: MDPI AG 2024-11-01
Series:Molecules
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Online Access:https://www.mdpi.com/1420-3049/29/23/5635
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author Krzysztof Sasak
Michał Nowak
Anna Wlodarczyk
Agata Sarniak
Dariusz Nowak
author_facet Krzysztof Sasak
Michał Nowak
Anna Wlodarczyk
Agata Sarniak
Dariusz Nowak
author_sort Krzysztof Sasak
collection DOAJ
description Numerous compounds that are scavengers of hydroxyl radicals (•OH) in Fenton systems have low solubility in water. Therefore, they are dissolved in organic solvents to reach suitable concentrations in the reaction milieu of the Fenton system. However, these solvents may react with •OH and iron, leading to significant errors in the results. We evaluated 11 solvents (4 alcohols, acetone, 4 esters, dimethyl-sulfoxide, and acetonitrile) at concentrations ranging from 0.105 µmol/L to 0.42 µmol/L to assess their effects on light emission, a recognized measure of •OH radical activity, in the Fe<sup>2+</sup>-EGTA-H<sub>2</sub>O<sub>2</sub> system. Six solvents inhibited and four solvents enhanced light emission at all tested concentrations. Acetonitrile, which initially suppressed light emission, lost this effect at a concentration of 0.105 µmol/L, (−1 ± 13 (2; 0) %, <i>p</i> > 0.05). Methanol, at the lowest tested concentration, inhibited light emission by 62 ± 4% (<i>p</i> < 0.05), while butyl butyrate enhanced it by 93 ± 16% (<i>p</i> < 0.05). These effects may be explained by solvent-driven •OH-scavenging, inhibition or acceleration of Fe2+ regeneration, or photon emission from excited solvent molecules. Our findings suggest that acetonitrile seems suitable for preparing stock solutions to evaluate antioxidant activity in the Fe<sup>2+</sup>-EGTA-H<sub>2</sub>O<sub>2</sub> system, provided that the final concentration of this solvent in the reaction milieu is kept below 0.105 µmol/L.
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spelling doaj-art-f9d1b5c83d194b04b14b45d93f77b2532024-12-13T16:28:32ZengMDPI AGMolecules1420-30492024-11-012923563510.3390/molecules29235635Effect of Selected Organic Solvents on Hydroxyl Radical-Dependent Light Emission in the Fe<sup>2+</sup>-EGTA-H<sub>2</sub>O<sub>2</sub> SystemKrzysztof Sasak0Michał Nowak1Anna Wlodarczyk2Agata Sarniak3Dariusz Nowak4Department of Medical Imaging Techniques, Medical University of Lodz, Lindleya 6, 90-131 Lodz, PolandRadiation Protection, University Hospital No 2, Medical University of Lodz, Zeromskiego 113, 90-549 Lodz, PolandDepartment of Sleep Medicine and Metabolic Disorders, Medical University of Lodz, Mazowiecka 6/8, 92-215 Lodz, PolandDepartment of Clinical Physiology, Medical University of Lodz, Mazowiecka 6/8, 92-215 Lodz, PolandDepartment of Clinical Physiology, Medical University of Lodz, Mazowiecka 6/8, 92-215 Lodz, PolandNumerous compounds that are scavengers of hydroxyl radicals (•OH) in Fenton systems have low solubility in water. Therefore, they are dissolved in organic solvents to reach suitable concentrations in the reaction milieu of the Fenton system. However, these solvents may react with •OH and iron, leading to significant errors in the results. We evaluated 11 solvents (4 alcohols, acetone, 4 esters, dimethyl-sulfoxide, and acetonitrile) at concentrations ranging from 0.105 µmol/L to 0.42 µmol/L to assess their effects on light emission, a recognized measure of •OH radical activity, in the Fe<sup>2+</sup>-EGTA-H<sub>2</sub>O<sub>2</sub> system. Six solvents inhibited and four solvents enhanced light emission at all tested concentrations. Acetonitrile, which initially suppressed light emission, lost this effect at a concentration of 0.105 µmol/L, (−1 ± 13 (2; 0) %, <i>p</i> > 0.05). Methanol, at the lowest tested concentration, inhibited light emission by 62 ± 4% (<i>p</i> < 0.05), while butyl butyrate enhanced it by 93 ± 16% (<i>p</i> < 0.05). These effects may be explained by solvent-driven •OH-scavenging, inhibition or acceleration of Fe2+ regeneration, or photon emission from excited solvent molecules. Our findings suggest that acetonitrile seems suitable for preparing stock solutions to evaluate antioxidant activity in the Fe<sup>2+</sup>-EGTA-H<sub>2</sub>O<sub>2</sub> system, provided that the final concentration of this solvent in the reaction milieu is kept below 0.105 µmol/L.https://www.mdpi.com/1420-3049/29/23/5635chemiluminescenceFenton systemhydroxyl radicalsorganic solventsaprotic solvents
spellingShingle Krzysztof Sasak
Michał Nowak
Anna Wlodarczyk
Agata Sarniak
Dariusz Nowak
Effect of Selected Organic Solvents on Hydroxyl Radical-Dependent Light Emission in the Fe<sup>2+</sup>-EGTA-H<sub>2</sub>O<sub>2</sub> System
Molecules
chemiluminescence
Fenton system
hydroxyl radicals
organic solvents
aprotic solvents
title Effect of Selected Organic Solvents on Hydroxyl Radical-Dependent Light Emission in the Fe<sup>2+</sup>-EGTA-H<sub>2</sub>O<sub>2</sub> System
title_full Effect of Selected Organic Solvents on Hydroxyl Radical-Dependent Light Emission in the Fe<sup>2+</sup>-EGTA-H<sub>2</sub>O<sub>2</sub> System
title_fullStr Effect of Selected Organic Solvents on Hydroxyl Radical-Dependent Light Emission in the Fe<sup>2+</sup>-EGTA-H<sub>2</sub>O<sub>2</sub> System
title_full_unstemmed Effect of Selected Organic Solvents on Hydroxyl Radical-Dependent Light Emission in the Fe<sup>2+</sup>-EGTA-H<sub>2</sub>O<sub>2</sub> System
title_short Effect of Selected Organic Solvents on Hydroxyl Radical-Dependent Light Emission in the Fe<sup>2+</sup>-EGTA-H<sub>2</sub>O<sub>2</sub> System
title_sort effect of selected organic solvents on hydroxyl radical dependent light emission in the fe sup 2 sup egta h sub 2 sub o sub 2 sub system
topic chemiluminescence
Fenton system
hydroxyl radicals
organic solvents
aprotic solvents
url https://www.mdpi.com/1420-3049/29/23/5635
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