Fabrication of Bismuth-Chitosan modified Glassy Carbon Electrode and its application in

measurement of Tartrazine in Food and Drug sample

Supervisor: Dr Karim Asadpour-ZeynaliAdvisor: Dr Esmaeel Alipour

Presented by: Mozhdeh Aleshi

Master thesis presentation in Analytical Chemistry

Modified Electrodes Introduction : Synthetic Colorants: Tartrazine

Measurement of Tartrazine Experimental

Results and Discussions

Conclusions

2

Contents

Modified Electrodes: properties Bismuth-modified electrode

• Modification methods

1. Ex-situ plating

2. In-situ plating

3. Bi2O3

3

Introduction

PropertiesWide potential range

Low background

Insensitive to oxygen

Non-toxicity

4

Introduction

A B

KBr role in modification process by ex-situ method

5

Introduction

deacetylation

Chitosan properties : non-toxic, hydrophilic,…

Chitosan:

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IntroductionFood Additives

ColorantsNatural

Synthetic

preservatives

Anti-oxidants

pH regulators

Azo dyes

Color Index(C.I)

FD & C

TartrazineAlso known as : E102 / C.I.19140 / FD&C yellow acid 5

میزان مجاز استفاده از تارتارازین در محصوالت غذایی مختلف1-1جدول

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•Spectrophotometery

•HPLC

•Electrochemical

Measurement of Tartrazine

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•working electrode: Bi-Chit GCE•auxiliary electrode: Pt Electrode•Reference: SCE(Saturated Calomel Electrode)

Optimum conditions :

ex-situ method, 0.18mg/ml Bi, KBr 0.05 mg/ml, pH=4.5, acetate 0.1M, - 0.75 V,

200s (stirring solution)

Techniques: Differential pulse voltammetryCyclic VoltammetryHydrodynamic Amperometery

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Experimental

Results & Discussions

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Electrochemical behavior of Tartrazine

• pH

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:Optimization Of Electrode modifying parameters

1 2 3 4 4.5 50

0.51

1.52

2.53

3.54

pH

ip(µA)

pH=4.5

•Bismuth concentration

0.04 0.1 0.15 0.18 0.2 0.24 0.28 0.3 0.350

0.5

1

1.5

2

2.5

3

3.5

4

C(mg/ml)

i/µA

C=0.18 mg/ml

Preconcentration time Preconcentration potential

Eapp= -0.75 V.vs SCE t =200s

0.6 0.7 0.75 0.8 0.85 0.9 0.95 10

0.5

1

1.5

2

2.5

3

-E/V

i/µA

100 120 140 160 200 220 2400

0.5

1

1.5

2

2.5

3

3.5

t/s

ip/µA

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Characterization of Bi-Chit modified GCE

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EDAX report of Bi-Chit modified GCE

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Optimization of Tartrazine measurement parameters:

2e− + 2H+ + (R–N=N–R1) → (R–NH–NH–R1) (1) 2e− + 2H+ + (R–NH–NH–R1) → (R–NH2) + (R1–NH2) (2)

pH

Buffer concentration

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C= 0.3M

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Effect of Scan rate

Choronoamperometery

n = 2, F = 96487, A= 0.0314 cm2

7.56 D = 4.89 × 10-6 cm2s-1

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Effect of Tartrazine’s concentration

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Calibration carve(DPV method)

0 0.5 1 1.5 2 2.5 30

5

10

15

20

25

f(x) = 5.89623603512299 x + 5.56511511728522R² = 0.995480892816706

f(x) = 10.5922671517876 x + 1.14483420874427R² = 0.993947178792963

C(mM)

i(µA)

XLOD = 3 Sb/b XLOD = 16 µM or 8.550 µg/ml

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Hydrodynamic Amperometery

XLOD = 3 Sb/b XLOD =12.098µM or 6.464 µg/ml

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•Drug sample: bisacodyle tablets

Analytical determination of TT in Real samples

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•Food sample: Eminem(yellow)

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RSD% Amount of TT per tablet/ eminem Analysis No. Sample

1.1570.5200 1

Bisacodyle0.5215 20.5130 3

1.1471.190 1

Eminem(yellow)1.144 21.120 3•0.515mg/per tablet

•1.13 mg/per eminem

Recovery% Cspike/mM Ĉspike/mM Analysis No. Sample

102 0.051 0.05 1Bisacodyle

92 0.046 0.05 2

96 0.048 0.05 3

97.06 0.0388 0.04 1Eminem

101.68 0.0404 0.04 2

91.125 0.0364 0.04 3

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Investigation the accuracy of proposed method

• The proposed method for measurement of Tartrazine is simple, inexpensive and practical.

•The modified Electrode indicated better electrocatalytic reactivity Towards Tartrazine in comparison to Glassy carbon Electrode.

•The Bismuth-Chit Glassy carbon Electrode was successfully used for determination of Tartrazine in real samples.

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Conclusions

• The proposed electrode can be used for determination and measurement of other

synthetic colorants such as sunset yellow,carmoisin,quinoline yellow.

•Application of proposed modified electrode for measurement of some pharmaceutical

compounds

•Application of Chitosan-modified Electrode for further experiments

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Suggestions

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