Exploring MBTH as a spectrophotometric probe for the determination of total phenolic compounds in beverage samples

Granja, Bruna da Silva; Filho, José Ricardo Honório de Mendonça; Oliveira, Woodland de Souza; Santos, Josué Carinhanha Caldas

doi:10.1039/c8ay00464a

Cited by 6 publications

(6 citation statements)

References 30 publications

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“…521 Da Silva Granja et al evaluated 114 among other methods for the determination of total phenol content (203, FC assay, ABTS assay, DPPH 109 assay) and found it to be equally useful. 500 The reaction with 114 works in dilute H 2 SO 4 500,521 and at at pH 8−9, 522,523 contrary to the typically neutral to basic conditions required by reagents 203 and 204. Oxidations are typically performed with K 3 [Fe(CN) 6 ], FeCl 3 , or K 2 S 2 O 8 .…”

Section: Electrophilic Aromatic Substitution (S Ear ) With Activated ...mentioning

confidence: 99%

“…Reducing power of the matrix can be problematic in detecting phenols, particularly in biological media with many reducing compounds ( e.g ., ascorbic acid, sulphites, reducing sugars) . Hence, reaction-based methods that integrate the phenol into a chromo- or fluorogenic product have proven superior in sensitivity .…”

Section: Chromo- and Fluorogenic Probes For Phenolsmentioning

confidence: 99%

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Enlightening the Path to Protein Engineering: Chemoselective Turn-On Probes for High-Throughput Screening of Enzymatic Activity

et al. 2023

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Many successful stories in enzyme engineering are based on the creation of randomized diversity in large mutant libraries, containing millions to billions of enzyme variants. Methods that enabled their evaluation with high throughput are dominated by spectroscopic techniques due to their high speed and sensitivity. A large proportion of studies relies on fluorogenic substrates that mimic the chemical properties of the target or coupled enzymatic assays with an optical read-out that assesses the desired catalytic efficiency indirectly. The most reliable hits, however, are achieved by screening for conversions of the starting material to the desired product. For this purpose, functional group assays offer a general approach to achieve a fast, optical read-out. They use the chemoselectivity, differences in electronic and steric properties of various functional groups, to reduce the number of false-positive results and the analytical noise stemming from enzymatic background activities. This review summarizes the developments and use of functional group probes for chemoselective derivatizations, with a clear focus on screening for enzymatic activity in protein engineering.

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Section: Electrophilic Aromatic Substitution (S Ear ) With Activated ...mentioning

confidence: 99%

Section: Chromo- and Fluorogenic Probes For Phenolsmentioning

confidence: 99%

Enlightening the Path to Protein Engineering: Chemoselective Turn-On Probes for High-Throughput Screening of Enzymatic Activity

et al. 2023

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“…For the MBTH method, VP reacts with MBTH in presence of Fe(III) as an oxidizing agent through oxidative coupling (Scheme 2) yielding a colored product with an absorption maximum at 709 nm (Fig. 5c) (Ribeiro et al, 2009;El-Yazbi et al, 1993a;El-Kommos, 1987;El-Yazbi et al, 1984;El-Yazbi et al, 1993b;El-Yazbi et al, 1999;El-Ragehy et al, 2001;Sowjanya et al, 2011;Anthon & Barrett, 2004;Granja et al, 2018). On oxidation of MBTH with the oxidant, Fe(III) chloride, MBTH loses two electrons and one proton resulting in the formation of the active coupling species called electrophilic intermediate (Ribeiro et al, 2009;El-Yazbi et al, 1993a;El-Kommos, 1987;El-Yazbi et al, 1984;El-Yazbi et al, 1993b;El-Yazbi et al, 1999;El-Ragehy et al, 2001;Sowjanya et al, 2011;Anthon & Barrett, 2004;Granja et al, 2018).…”

Section: Determination Of Vp In Presence Of Sf Using Mbthmentioning

confidence: 99%

“…5c) (Ribeiro et al, 2009;El-Yazbi et al, 1993a;El-Kommos, 1987;El-Yazbi et al, 1984;El-Yazbi et al, 1993b;El-Yazbi et al, 1999;El-Ragehy et al, 2001;Sowjanya et al, 2011;Anthon & Barrett, 2004;Granja et al, 2018). On oxidation of MBTH with the oxidant, Fe(III) chloride, MBTH loses two electrons and one proton resulting in the formation of the active coupling species called electrophilic intermediate (Ribeiro et al, 2009;El-Yazbi et al, 1993a;El-Kommos, 1987;El-Yazbi et al, 1984;El-Yazbi et al, 1993b;El-Yazbi et al, 1999;El-Ragehy et al, 2001;Sowjanya et al, 2011;Anthon & Barrett, 2004;Granja et al, 2018). The carbon atom with maximum electron density in VP is attacked by the electrophile (Scheme 2) yielding the deep blue product with a specific absorption maximum at 709 nm specific to VP (Ribeiro et al, 2009;El-Yazbi et al, 1993a;El-Kommos, 1987;El-Yazbi et al, 1984;El-Yazbi et al, 1993b;El-Yazbi et al, 1999;El-Ragehy et al, 2001;Sowjanya et al, 2011;Anthon & Barrett, 2004;Granja et al, 2018).…”

Section: Determination Of Vp In Presence Of Sf Using Mbthmentioning

confidence: 99%

“…On oxidation of MBTH with the oxidant, Fe(III) chloride, MBTH loses two electrons and one proton resulting in the formation of the active coupling species called electrophilic intermediate (Ribeiro et al, 2009;El-Yazbi et al, 1993a;El-Kommos, 1987;El-Yazbi et al, 1984;El-Yazbi et al, 1993b;El-Yazbi et al, 1999;El-Ragehy et al, 2001;Sowjanya et al, 2011;Anthon & Barrett, 2004;Granja et al, 2018). The carbon atom with maximum electron density in VP is attacked by the electrophile (Scheme 2) yielding the deep blue product with a specific absorption maximum at 709 nm specific to VP (Ribeiro et al, 2009;El-Yazbi et al, 1993a;El-Kommos, 1987;El-Yazbi et al, 1984;El-Yazbi et al, 1993b;El-Yazbi et al, 1999;El-Ragehy et al, 2001;Sowjanya et al, 2011;Anthon & Barrett, 2004;Granja et al, 2018). Figure 5c demonstrates the absorption spectra for the deep blue product obtained from VP solution alone and in presence of SF, showing no interference from SF with the absorption maximum of VP-colored product.…”

Section: Determination Of Vp In Presence Of Sf Using Mbthmentioning

confidence: 99%

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Eco-friendly analytical methods for the determination of compounds with disparate spectral overlapping: application to antiviral formulation of sofosbuvir and velpatasvir

et al. 2021

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Green analytical chemistry is one of the newest trends in analytical chemistry nowadays targeting the concept of green laboratory practices on chemists and environment. In this text, green practices are proposed in this work for the determination of sofosbuvir (SF) and velpatasvir (VP) in their pharmaceutical formulation. The analysis of SF in a binary mixture with VP represents an analytical challenge due to the complete overlapping of the UV spectrum of SF by that of VP. Therefore, the direct absorbance and derivative measurements cannot resolve such interference and failed to determine SF. In this paper, three direct and simple methods were developed for the analysis of SF without any interference from VP without sample pre-treatment. The proposed methods include measuring the second derivative amplitude of the ratio spectrum of the mixture using VP as a divisor, measuring the absorbance difference of the mixture in NaOH solution against its HCl solution, and using the derivative compensation technique. On the other hand, VP was determined specifically in presence of SF by two methods. Firstly, by its reaction with 4-chloro-7-nitrobenzofurazan (NBD-Cl) where the reaction product was measured spectrophotometrically and spectrofluorometrically and secondly through the reaction of VP with 3-methyl-2-benzothiazolinone hydrazone hydrochloride (MBTH). The calibration curves showed good correlation coefficient (r2 > 0.999). The developed methods were highly precise with RSD% values less than 2%. The method greenness profile was compared with other published methods by applying the eco-scale protocol. Assessment results proved that our analytical procedure is greener than other reported methods. Moreover, upon comparison with other methods, the proposed methods showed better or comparable sensitivity in addition to being inexpensive and ecofriendly. Accordingly, these methods could be readily applied for quality control purposes as an eco-friendly, simple and efficient analytical tool.

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Optical biosensor for catechol determination based on laccase‐immobilized anionic polyamide 6 microparticles

Cano‐Raya

Dencheva

Braz

et al. 2020

J of Applied Polymer Sci

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This work presents the preparation, optimization, and testing of an enzymebased optical biosensor for catechol determination. The sensing area is attached to a glass support and contains: anionic polyamide 6 (PA6) porous microparticles supporting laccase from Trametes Versicolor, embedded in a Pebax ® MH1657 polymer binder that contains the optical indicator dye 3-methyl-2-benzothiazolinone hydrazone (MBTH), responsible for the optical transduction. The catechol analyte, after its enzymatic oxidation, forms o-benzoquinone that can be detected by oxidative coupling with MBTH giving rise to a colored product. The latter can be quantified measuring the UV/VIS absorbance at 500 nm. The PA6 microparticles performed as useful laccase carriers reaching high immobilization yields of up to 99.8% and preserving the enzyme catalytic activity. This permitted the preparation of a new biosensor presenting a detection limit of 11 μM and responding linearly to up to 118 μM of catechol. Biosensor applicability was tested in spiked natural water samples from river and spring. The recovery rates observed were in the range of 97-108% that proves the good accuracy of the proposed biosensor.

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Exploring MBTH as a spectrophotometric probe for the determination of total phenolic compounds in beverage samples

Abstract: An alternative method using MBTH as a spectrophotometric probe for the determination of total phenolic compounds in samples of wines (red and white), coffees (instant and brewed), teas and infusions.

Cited by 6 publications

References 30 publications

Enlightening the Path to Protein Engineering: Chemoselective Turn-On Probes for High-Throughput Screening of Enzymatic Activity

Enlightening the Path to Protein Engineering: Chemoselective Turn-On Probes for High-Throughput Screening of Enzymatic Activity

Eco-friendly analytical methods for the determination of compounds with disparate spectral overlapping: application to antiviral formulation of sofosbuvir and velpatasvir

Optical biosensor for catechol determination based on laccase‐immobilized anionic polyamide 6 microparticles

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