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Poliphenols detection in wines

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Information about Poliphenols detection in wines

Published on July 2, 2008

Author: Skoo84

Source: slideshare.net

Description

This is my thesis for master degree of chemistry. We made a biosensor for detection of polyphenols from wines. They are imporant antioxidants.
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Partea Teoretică Cuvinte Cheie

 

 

 

Obiectiv

Aparatură şi materiale

Apă distilată K 3 [Fe(CN 6 )] KCl ” Reactivul“ Bucuresti Fenol NaH 2 PO 4 si Na 2 HPO 4 Nafion Albumină din ser bovin (BSA)‏ Glutaraldehidă (GA)‏ Catechol Tirozinază, din ciuperci, EC.1.14.18.1, 2085 u/mg, pudră liofilizată (Ty)‏

Ty BSA GA Nafion

Rezultate ş i discu ţ ii

Voltamograma ciclica a catecolului pe electrod de grafit Condiţii experimentale: tampon fosfat 0.1 M, pH 6.74; potenţial de start -0.8 V, viteza de baleiaj, 50 mV/s.

Voltamograma ciclică a fenolului pe bioelectrod G/Ty-BSA-Nafion Condiţii experimentale: tampon fosfat 0.1 M, pH 6.74; potenţial de start -0.8 V, viteza de baleiaj, 50 mV/s. Voltamograma ciclică a catecolului pe bioelectrod G/Ty-BSA-Nafion Condiţii experimentale: tampon fosfat 0.1 M, pH 6.74; potenţial de start -0.8 V, viteza de baleiaj, 50 mV/s.

Voltamograma ciclica a 0.1 mM K 3 [Fe(CN) 6 ] pe bioelectrod G/Ty-BSA-Nafion Condiţii experimentale: potenţial de start -0.1 V.

Dependenţa log I vs. log v (A) si I vs. v 1/2 (B). I p = 2.69*10 -5 n 3/2 A D 0 1/2 v 1/2 C o * 0.9982 / 7 0.9965 / 7 R/n 0.43  0.004 0.4  0.008 catodic anodic Panta dependenţei log I vs . log v

Stabilitatea bioelectrodului G/Ty-BSA-Nafion Condiţii experimentale: 0.1 mM K 3 [Fe(CN) 6 ] + 0.1 M KCl, potential de start -0.1 V, 50 mV/s.

Parametrii analitici ai biosenzorului G/Ty-BSA-GA-Nafion

H 2 0 O 2 Ty Chinona Catecol ne - Ty Fenol H 2 0 O 2 Ty o-Chinona Catecol ne - O 2

Î nregistrările I vs. timp pentru bioelectrodul G/Ty-BSA-GA-Nafion Condiţii experimentale: potenţial aplicat, 0.05 V vs. Ag/AgCl, KCl sat , tampon fosfat 0.1 M, pH 6.74; agitare continuă controlată de EDR, ω = 1500 rpm. Curba de calibrare a bioelectrodului G/Ty-BSA-GA-Nafion Condiţii experimentale: poten ţ ia l aplicat, 0.05 V vs. Ag/AgCl, KClsat, tampon fosfat 0.1 M, pH 6.74; agitare continuă controlată de EDR, ω = 1500 rpm.

 

 

 

Lin e arizarea Lineweaver-Burk (A), Eadie-Hofstee (B) si Hanes-Woolf (C) pentru bioelectrodul G/Ty-BSA-GA-Nafion. Condi ţ ii experimentale: potenţial aplicat, 0.05 V vs. Ag/AgCl, KClsat, tampon fosfat 0.1 M, pH 6.74; agitare continu ă controlat ă de EDR, ω = 1500 rpm. A B C

Valorile paramterilor cinetici pentru biosenzorul G/Ty-BSA-GA-Nafion 0.9994/ 22 0.0791 3.11 e -6 3.93 e -5 Linearizare Hanes-Woolf 0.9835 / 25 0.0651 3.12 e - 6 4.79 e -5 Linearizare Eadie-Hofstee 0.9978 / 22 0.0676 3.17 e -6 4.69 e -5 Linearizare Lineweaver-Burk 0.9989 / 25 0.0556 3.2 e -6 ± 2.3 e -8 5.75 e -5 ± 1.394 e -6 Fitare Origin R/n S / A/M I max / A K M / M

Concluzii

Imobilizarea enzimei s-a realizat cu ajutorul unui amestec de BSA si GA Peak urile de oxidare caracteristice catecolului si fenolului sunt deplasate spre valori mai pozitive Curbele de calibrare a bioelectrodului G/Ty-BSA-GA-Nafion au permis determinarea următorilor parametrii analitici: timpul de răspuns < 30 s, domeniul de linearitate 0 - 0.04 mM catechol si sensibilitatea 0.0333  A/mM Reprezent ă rile grafice liniare ale I vs. v 1/2 sugereaz ă un comportament difuziv al speciei la electrod, deci o bun ă permeabilitate a filmului.

- Imobilizarea enzimei s-a realizat cu ajutorul unui amestec de BSA si GA -Peak urile de oxidare caracteristice catecolului si fenolului sunt deplasate spre valori mai pozitive -Curbele de calibrare a bioelectrodului G/Ty-BSA-GA-Nafion au permis determinarea următorilor parametrii analitici: timpul de răspuns < 30 s, domeniul de linearitate 0 - 0.04 mM catechol si sensibilitatea 0.0333  A/mM -Reprezent ă rile grafice liniare ale I vs. v 1/2 sugereaz ă un comportament difuziv al speciei la electrod, deci o bun ă permeabilitate a filmului.

V ă mulţumesc pentru atenţie!

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