Download - thesis presentation
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:
6
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
7
•Spectrophotometery
•HPLC
•Electrochemical
Measurement of Tartrazine
8
•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
9
Experimental
Results & Discussions
10
11
Electrochemical behavior of Tartrazine
• pH
12
: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
13
14
Characterization of Bi-Chit modified GCE
15
EDAX report of Bi-Chit modified GCE
16
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
17
C= 0.3M
18
Effect of Scan rate
Choronoamperometery
n = 2, F = 96487, A= 0.0314 cm2
7.56 D = 4.89 × 10-6 cm2s-1
19
Effect of Tartrazine’s concentration
20
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
21
Hydrodynamic Amperometery
XLOD = 3 Sb/b XLOD =12.098µM or 6.464 µg/ml
22
•Drug sample: bisacodyle tablets
Analytical determination of TT in Real samples
23
•Food sample: Eminem(yellow)
24
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
25
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.
26
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
27
Suggestions
28