Simple, sensitive and on‐line fluorescence monitoring of photodegradation of phenol and 2‐naphthol

He, Yunlong; Lv, Yi; Hu, Jing; Qı, Lei; Hou, Xiandeng

doi:10.1002/bio.964

Cited by 5 publications

(4 citation statements)

References 37 publications

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“…Indeed, it was recognized that thermodynamically the formation of a phenoxyl radical is more favorable than • OH additions . Moreover, in substituted phenols the substituent have a marked influence on directing the incoming • OH. ,, A number of techniques which essentially are chemical, biological, catalytic, and electrochemical procedures were reported for the • OH induced degradation of naphthols in wastewater. − Also, the free electron transfer phenomena of naphthols, their analogues, and derivatives has been extensively studied by fluorescence, laser flash, and pulse radiolysis techniques in organic solvents. − To our knowledge there has not been any comprehensive report of the kinetics, mechanism, and intermediate species produced during the one-electron oxidations of both naphthol molecules with • OH in aqueous medium.…”

Section: Introductionmentioning

confidence: 99%

Oxidation Reactions of 1- and 2-Naphthols: An Experimental and Theoretical Study

et al. 2013

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The transients formed during the reactions of oxidizing radicals with 1-naphthol (1) and 2-naphthol (2) in aqueous medium have been investigated by pulse radiolysis with detection by absorption spectroscopy and density functional theory (DFT) calculations. The transient spectra formed on hydroxyl radical ((•)OH) reactions of 1 and 2 exhibited λ(max) at 340 and 350 nm at neutral pH. The rate constants of the (•)OH reactions of 1 (2) were determined from build-up kinetics at λ(max) of the transients as (9.63 ± 0.04) × 10(9) M(-1) s(-1) ((7.31 ± 0.11) × 10(9) M(-1) s(-1)). DFT calculations using the B3LYP/6-31+G(d,p) method have been performed to locate favorable reaction sites in both 1 and 2 and identification of the pertinent transients responsible for experimental results. Calculations demonstrated that (•)OH additions can occur mostly at C1 and C4 positions of 1, and at C1 and C8 positions of 2. Among several isomeric (•)OH adducts possible, the C1 adduct was found to be energetically most stable both in 1 and 2. Time-dependent density functional theory (TDDFT) calculations in the solution phase has shown that the experimental spectrum of 1 was mainly attributed by 1a4 (kinetically driven (•)OH-adduct) formed via the addition of (•)OH at the C4 position which was 0.73 kcal/mol endergonic compared to 1a1 (thermodynamic (•)OH adduct), whereas 2a1 (thermodynamic/kinetic (•)OH-adduct) was mainly responsible for the experimental spectrum of 2. Naphthoxyl radicals of 1 and 2 have been predicted as the transient formed in the reaction of (•)OH at basic pH. In addition, the same transient species resulted from the reactions of oxide radical ion (O(•-)) at pH ≈ 13 and azide radical (N3(•)) at pH 7 with 1 and 2. Further, UV photolysis of aqueous solutions of 1 and 2 containing H2O2 (UV/H2O2) were used for the (•)OH induced oxidation product formations up on 60% degradations of 1 and 2; profiling of the oxidation products were performed by using an ultraperformance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) method. According to the UPLC-Q-TOF-MS analyses, the preliminary oxidation products are limited to dihydroxy naphthalenes and naphthoquinones with N2-saturation, while some additional products (mainly isomeric monohydroxy-naphthoquinones) have been observed in the degradations of 1 and 2 in the presence of O2. We postulate that dihydroxy naphthalenes are derived explicitly from the most favorable (•)OH-adducts speculated (preference is in terms of the kinetic/thermodynamic dominancy of transients) by using theoretical calculations which in turn substantiate the proposed reaction mechanisms. The observations of (•)OH-adducts for an aromatic phenol (herein for both 1 and 2 at pH 7) rather than phenoxyl type radical in the pulse radiolysis experiments is a distinct and unique illustration. The present study provides a meaningful basis for the early stages associated with the (•)OH initiated advanced oxidation processes of 1- and 2-naphthols.

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Section: Introductionmentioning

confidence: 99%

Oxidation Reactions of 1- and 2-Naphthols: An Experimental and Theoretical Study

et al. 2013

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“…Subsequently, the Ab 1 can specifically bind with Fe(OH) 3 @Ab 2 , which can rapidly quench the fluorescence of 4-CN. Significantly, the fluorescence quenching effect may be attributed to the oxidation of 4-CN caused by the valence transition of the ferric ion in Fe(OH) 3 nanocages [ 41 , 42 ]. Subsequently, the uncombined Fe(OH) 3 @Ab 2 was collected for the colorimetric detection, where the Fe(OH) 3 can catalyze the oxidation of ABTS to generate a vivid color change and UV–vis absorption intensity variation.…”

Section: Resultsmentioning

confidence: 99%

Coordinating Etching Inspired Synthesis of Fe(OH)3 Nanocages as Mimetic Peroxidase for Fluorescent and Colorimetric Self-Tuning Detection of Ochratoxin A

2023

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The development of multifunctional biomimetic nanozymes with high catalytic activity and sensitive response is rapidly advancing. The hollow nanostructures, including metal hydroxides, metal-organic frameworks, and metallic oxides, possess excellent loading capacity and a high surface area-to-mass ratio. This characteristic allows for the exposure of more active sites and reaction channels, resulting in enhanced catalytic activity of nanozymes. In this work, based on the coordinating etching principle, a facile template-assisted strategy for synthesizing Fe(OH)3 nanocages by using Cu2O nanocubes as the precursors was proposed. The unique three-dimensional structure of Fe(OH)3 nanocages endows it with excellent catalytic activity. Herein, in the light of Fe(OH)3-induced biomimetic nanozyme catalyzed reactions, a self-tuning dual-mode fluorescence and colorimetric immunoassay was successfully constructed for ochratoxin A (OTA) detection. For the colorimetric signal, 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) can be oxidized by Fe(OH)3 nanocages to form a color response that can be preliminarily identified by the human eye. For the fluorescence signal, the fluorescence intensity of 4-chloro-1-naphthol (4-CN) can be quantitatively quenched by the valence transition of Ferric ion in Fe(OH)3 nanocages. Due to the significant self-calibration, the performance of the self-tuning strategy for OTA detection was substantially enhanced. Under the optimized conditions, the developed dual-mode platform accomplishes a wide range of 1 ng/L to 5 μg/L with a detection limit of 0.68 ng/L (S/N = 3). This work not only develops a facile strategy for the synthesis of highly active peroxidase-like nanozyme but also achieves promising sensing platform for OTA detection in actual samples.

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“…The broader signals of the polymer may mean that the polymer has an extended π-conjugation system derived from the BINOL backbone. Changes in emission spectra of BINOL and related compounds due to their photo degradation have been reported [31,41,42]; however, polymer formation during the photo reactions have never been proposed.…”

Section: Resultsmentioning

confidence: 99%

Photo Racemization and Polymerization of (R)-1,1′-Bi(2-naphthol)

Zhang

2016

Molecules

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(R)-1,1'-Bi(2-naphthol) ((R)-BINOL) in an acetonitrile solution lost optical activity upon irradiation with an Hg-Xe lamp. HPLC resolution of the product indicated that (R)-BINOL was racemized upon irradiation, and SEC analysis suggested that a polymeric product was formed in the course of racemization. It is proposed that polymerization of BINOL can occur before it is racemized and that a unit in a polymer derived from BINOL may lose its optical activity afterwards due to in-chain racemization and/or reduction. The polymeric products seem to consist not only of BINOL residues but also of residues derived from acetonitrile as well as those derived through reduction of BINOL.

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Simple, sensitive and on‐line fluorescence monitoring of photodegradation of phenol and 2‐naphthol

Cited by 5 publications

References 37 publications

Oxidation Reactions of 1- and 2-Naphthols: An Experimental and Theoretical Study

Oxidation Reactions of 1- and 2-Naphthols: An Experimental and Theoretical Study

Coordinating Etching Inspired Synthesis of Fe(OH)3 Nanocages as Mimetic Peroxidase for Fluorescent and Colorimetric Self-Tuning Detection of Ochratoxin A

Photo Racemization and Polymerization of (R)-1,1′-Bi(2-naphthol)

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