Evaluation of analytical techniques for organic peroxide measurements in polar and non-polar systems.
Notice bibliographique
Résumé
Peroxides and hydroperoxides are generated during the oxidation of volatile organic compounds (VOCs) in both gaseous and aqueous phases. The ozonolysis of alkenes in the gas phase is a significant source of peroxy radicals (RO2) in both nocturnal and diurnal chemistry. In the absence of NO, the recombination reactions of RO2 radicals lead to the formation of H2O2 and/or organic hydroperoxides (Atkinson, 2000). Hydroperoxides are highly reactive and play a crucial role in atmospheric chemistry, such as the oxidation of SO2 to H2SO4 in atmospheric aqueous droplets and heterogeneous SO2 uptake (Wang, 2021). Moreover, peroxides are suggested to constitute a significant fraction of laboratory-generated secondary organic aerosol (SOA) (Docherty 2005) and can serve as reservoirs of HOx and ROx radicals (Li, 2016).Various spectrophotometric methods have been employed to quantify SOA-bound peroxides offline. The Iodometry method quantifies peroxides present in any form (H2O2, ROOH, and ROOR) except for tertiary dialkyl peroxides. The principle of the method is A faster and more sensitive alternative to this method was developed by our group, which accelerates the reaction by microwave heating (Alba-Elena, 2023). These assays typically use water as a solvent. Here, for the first time, an alternative procedure using 1-propanol as an organic solvent is proposed and tested for H2O2 and various less reactive peroxides.Other spectrophotometric methods include: the 4-nitrophenyl boronic acid (NPBA) assay, which is based on the reaction between the hydroperoxide and NPBA to form the colored nitrophenol, the absorbance of which is measured (Jiang, 2017), and the Fenton reaction-assisted ferrous-xylenol (FOX2) assay, which is based on the oxidation of Fe2+ by the organic hydroperoxide to form Fe3+, which forms a complex with Xylenol orange that can be detected spectrometrically (Morrison, 2023).All these assays, as well as the 2,7-dichlorofluorescein-based horseradish peroxidase (DCF-HRP) assay, a widely used fluorescence method that is more sensitive to H2O2 compared to other organic peroxides and hydroperoxides (Badali, 2015), have been tested using water and polar organic solvents such as 1-propanol and non-polar organic solvents such as chloroform. Their response to different types of peroxide: H2O2, tertbutyl hydroperoxide, ditertbutyl peroxide, methyl ethyl ketone peroxide, and dibenzoyl peroxide, has been evaluated. A comparative study of the results, their different characteristics, and their possible interferences has been conducted. ACKNOWLEDGEMENTThis research was supported by the Spanish Ministry of Science, Innovation and Universities (MICINN, https://www.ciencia.gob.es/) with grants PID2019-106468RB-I00 and PID2022-139724OB-I00, funded by MCIN/AEI/10.13039/501100011033 and co-funded by the European Union; the UCLM groups research grant No. 2022-GRIN-34199, funded by the own research plan of the UCLM for applied research projects, co-financed by the European Fund for Regional Development (FEDER). D. Alba thanks MCIN/AEI for his “Contrato Predoctoral” Ref BES-2020-094874 associated to the project indicated.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,012 | 0,016 |
| Méta-épidémiologie (sens strict) | 0,003 | 0,001 |
| Méta-épidémiologie (sens large) | 0,001 | 0,001 |
| Bibliométrie | 0,003 | 0,002 |
| Études des sciences et des technologies | 0,001 | 0,002 |
| Communication savante | 0,002 | 0,002 |
| Science ouverte | 0,002 | 0,003 |
| Intégrité de la recherche | 0,003 | 0,003 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,004 | 0,004 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».