Electrochemical detection in the high-performance liquid chromatographic analysis of plant phenolics

Chiàvari, Giuseppe; Concialini, V.; Galletti, Guido C.

doi:10.1039/an9881300091

Cited by 55 publications

(21 citation statements)

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“…Phloroglucinol and 3,5-dihydroxybenzoic acid had a much lower inductive effect on laccase activity than the rest of the compounds studied here, and their addition did not result in any color changes to the culture media. Both these compounds have been reported as weak laccase substrates which cannot be oxidized to quinones because their hydroxyl groups are in the meta position, resulting in a high redox potential (Chiavari et al, 1988). It has been suggested that they can be effective in stabilizing the enzyme, as opposed to having an inductive effect, indicating a potentially important role for these compounds in practical applications (Mai et al, 2000).…”

Section: Discussionmentioning

confidence: 99%

Structural close-related aromatic compounds have different effects on laccase activity and on lcc gene expression in the ligninolytic fungus Trametes sp. I-62

Terrón

González

Carbajo

et al. 2004

Fungal Genetics and Biology

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Section: Discussionmentioning

confidence: 99%

Structural close-related aromatic compounds have different effects on laccase activity and on lcc gene expression in the ligninolytic fungus Trametes sp. I-62

Terrón

González

Carbajo

et al. 2004

Fungal Genetics and Biology

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“…These phenolic compounds can be free phenolic groups in lignin or some of its aromatic degradation products. As an example, the standard potential E 0 of guaiacol amounts to +0.77 V (Chiavari et al 1988). Additional electron releasing groups attached to the guaiacol ring such as methoxy or alkyl groups further reduce its E 0 .…”

Section: Introductionmentioning

confidence: 99%

Degradation of chemically modified Scots pine (Pinus sylvestris L.) with Fenton reagent

Xie¹,

Xiao²,

Mai

2014

Holzforschung

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Abstract:The Fenton reaction is supposed to play a key role in the initial wood degradation by brown rot fungi. Wood was modified with 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU) and glutaraldehyde (GA) to various weight percentage gains in order to study if these types of modifications are able to reduce wood degradation by Fenton reagent. Veneers modified with higher concentrations (1.2 and 2.0 mol l -1 ) of both chemicals exhibited minor losses in mass and tensile strength during treatment with Fenton reagent, which shows restrained oxidative degradation by hydroxyl radicals. The decomposition rate of H 2 O 2 was lower in the Fenton solutions containing modified veneers than in those containing unmodified controls. More CO 2 evolved in systems containing unmodified veneers than in systems with modified veneers, indicating that modification protected wood from mineralisation. The reason for the enhanced resistance of modified wood to the Fenton reaction is attributed to impeded diffusion of the reagent into the cell wall rather than to inhibition of the Fenton reaction itself. The results show that wood modification with DMDHEU and GA is able to restrain the degradation of wood by the Fenton reaction and can explain why modified wood is more resistant to brown rot decay.

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“…[18][19][20] However, anodic detection of NP results in electrode fouling due to the formation of polymeric products on the electrode surface 20) as with other phenols. [21][22][23][24] Accordingly, in terms of the maintenance of electrode surfaces, cathodic reduction is regarded as a much more useful tool for ECD/HPLC analysis of NP than anodic oxidation.…”

Section: Resultsmentioning

confidence: 99%

High Performance Liquid Chromatography with an Electrochemical Detector in the Cathodic Mode as a Tool for the Determination of p-Nitrophenol and Assay of Acid Phosphatase in Urine Samples

et al. 2004

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Aromatic nitro compounds including nitrazepam, chloramphenicol, and p-nitrophenyl phosphate are often found in pharmaceuticals and as common reagents 1) for the assay of enzymes such as phosphatase and peptidase. The nitration of tyrosine residues in proteins has been recognized as an important process for regulating pathological conditions of various diseases induced by oxidative stress.2) Thus, general and sensitive methods for the determination of aromatic nitro compounds in biological fluids are needed.Spectrophotometric methods are currently used for the analysis of aromatic nitro compounds. As an alternative, cathodic detection can be considered, since aromatic nitro groups are known to undergo electrochemical reduction at a relatively positive potential. [3][4][5] Yet, few studies on the reductive detection of aromatic nitro compounds are to be found in the literature. [6][7][8] This is mainly because deoxygenation of the medium must be carried out for electrochemical detection in a cathodic mode.3,9-12) Otherwise, dissolved oxygen, whose potential for reduction is quite low at common electrodes such as carbons, exhibits a cathodic response, preventing the sensitive and reproducible determination of analytes. Notably in high performance liquid chromatography with an electrochemical detector (ECD/HPLC) in the cathodic mode, a rather tedious procedure must be applied continuously for a mobile phase. However, a cathodic ECD/HPLC system has the following advantages over other HPLC systems: (1) in general, downsizing of an electrochemical HPLC system is more feasible than that of a spectrophotometric one; (2) cathodically active compounds are rare in biological fluids, so there are fewer problems from interference or separation in comparison to anodic ECD/HPLC. To develop a useful bioanalytical method based on these advantages, especially the second, we tested a cathodic ECD/HPLC system as a sensitive and precise tool for the determination of p-nitrophenol (NP). Recently, ECD/HPLC systems with a dual mode have been developed for the determination of a nitrophenol analogue, nitrotyrosine. [13][14][15] The detection of nitrotyrosine using such systems comprises two electrochemical processes for transformation and detection as follows: cathodic reduction to the corresponding aminophenol at an upstream electrode and oxidation of the product at a downstream (detection) electrode. Although dual ECD/HPLC was demonstrated to provide a highly sensitive tool for the analysis of nitrotyrosine, a sophisticated electrochemical device is required and anodic oxidation-based detection will encounter problems with separation since biological fluids contain a large number of anodically active compounds. The purpose of this study is to take full advantage of the potential utility of cathodic detection, to develop a simple and general ECD/HPLC system for NP in biological samples. Herein, we report that utilizing not only a commercially available helium-purging device but also PEEK tubes for all tubing makes the ECD/HPLC system a ...

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Electrochemical detection in the high-performance liquid chromatographic analysis of plant phenolics

Cited by 55 publications

References 0 publications

Structural close-related aromatic compounds have different effects on laccase activity and on lcc gene expression in the ligninolytic fungus Trametes sp. I-62

Structural close-related aromatic compounds have different effects on laccase activity and on lcc gene expression in the ligninolytic fungus Trametes sp. I-62

Degradation of chemically modified Scots pine (Pinus sylvestris L.) with Fenton reagent

High Performance Liquid Chromatography with an Electrochemical Detector in the Cathodic Mode as a Tool for the Determination of p-Nitrophenol and Assay of Acid Phosphatase in Urine Samples

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