ix
TABLE OF CONTENTS
CHAPTER
1
TITLE
PAGE
DECLARATION
ii
DEDICATION
iii
ACKNOWLEDGEMENTS
iv
PREFACE
v
ABSTRACT
vii
ABSTRAK
viii
TABLE OF CONTENTS
ix
LIST OF TABLES
xvi
LIST OF FIGURES
xvii
LIST OF ABBREVIATIONS
xxi
LIST OF APPENDICES
xxiii
Introduction
1
1.1
Background of Study
1
1.2
Problem Statements
4
1.3
Objectives of Study
5
1.4
Scope of Study
5
1.5
Significance of Study
6
x
2
Literature Review
7
2.1
Diabetes Mellitus
7
2.2
Mesoporous Materials
8
2.2.1
MCM-41
9
2.2.2
Modification of MCM-41 with Metals
10
2.3
Selenium
12
2.3.1
Allotropes of Selenium
14
2.3.1.1
Vitreous Selenium
14
2.3.1.2
α- and β-monoclinic Selenium
14
2.3.1.3
Trigonal Selenium
15
2.3.2
2.4
2.5
3
Selenium Nanoparticles
16
Enzyme Immobilization
16
2.4.1
Adsorption
21
2.4.2
Entrapment
22
2.4.3
Covalent Binding
23
2.4.4
Cross-linking
23
2.4.5
Mesoporous Silica as Support for Enzyme
Immobilization
25
Electrochemical Sensors for Clinical Analysis
28
2.5.1
29
Glucose Biosensors
Materials and Methods
33
3.1
33
Chemicals and Reagents
xi
3.2
Instruments
34
3.3
Synthesis of MCM-41
35
3.4
Synthesis of Selenium Nanoparticles (SNs)
35
3.5
Incorporations of SNs with MCM-41 in the
Presence of APTES.
36
3.6
Leaching Studies
36
3.6.1
Decomposition of Se-MCM-41
37
3.6.2
Leaching Study of Se-MCM-41
38
3.7
Functionalization of MCM-41 with Amino Group
38
3.8
Functionalization of MCM-41-A and Se-MCM-41
with Aldehyde Group.
39
3.8.1
39
3.9
3.10
Tollen’s Reagent Method.
Characterizations of the MCM-41, SNs and SeMCM-41.
40
3.9.1
X-Ray Diffraction Spectroscopy Analysis
40
3.9.2
FTIR Spectroscopy
41
3.9.3
Field Emission Scanning Electron
Microscope
41
3.9.4
Thermal Electron Microscope
42
3.9.5
Thermal Gravimetric Analysis
Differential Thermal Analysis
and
42
Optimization of Immobilization of Glucose Oxidase
onto f-MCM-41 and f-Se-MCM-41
42
3.10.1
Effect of pH for Immobilization of Glucose
Oxidase onto f-MCM-41 and f-Se-MCM41.
43
3.10.2
Effect of GOx Concentration Used for the
Immobilization of Glucose Oxidase onto fMCM-41 and f-Se-MCM-41.
43
xii
3.11
Preparation of Reagents for the Determination of
Enzymatic Assay
44
3.11.1
Preparation of Sodium Acetate Buffer
(Reagent A)
44
3.11.2
Preparation of o-Dianisidine Solution
(Reagent B)
44
3.11.3
Preparation of β-D (+) Glucose Substrate
Solution (Reagent C)
45
3.11.4
Preparation of Reaction Cocktail (Reagent
D)
45
3.11.5
Preparation of Peroxidase Enzyme
Solution (Reagent E)
45
3.12
Determination of Enzymatic Assay using
Continuous Spectrophotometric Rate Determination
45
3.13
Determination of Protein Concentration using
Bradford Method
47
3.13.1
47
Preparation of Standard 3.1 mL Assay
Protocol
3.14
Determination of Specific Activity of Glucose
Oxidase
47
3.15
Leaching Test of the Immobilized f-MCM-41 and fSe-MCM-41
48
3.16
Immobilization of GOx onto f-MCM-41 and f-SeMCM-41.
48
3.17
Preparation of Working Electrode
49
3.18
Study on Electrochemical Properties of Glucose
Oxidase-Selenium Nanoparticles-MCM-41.
49
3.18.1
Effect of pH
50
3.18.2
Effect of Scan Rate
50
3.19
Sample Analysis Using Glucose Biosensor
50
xiii
4
Synthesis and Characterization of MCM-41, Se-MCM-41
and Glutaraldehyde Functionalized Se-MCM-41
51
4.1
Introduction
51
4.2
Synthesis and Calcination of MCM-41
52
4.3
Characterization of MCM-41
53
4.3.1
Analysis of MCM-41 with X-Ray
Diffraction Spectroscopy
53
4.3.2
Analysis of MCM-41 with
Transform Infrared Spectroscopy.
4.3.3
Analysis of MCM-41 with Thermal
Gravimetric Analysis
58
4.3.4
Analysis of MCM-41 with Field Emission
Scanning Electron Microscopy
59
4.3.5
Analysis of MCM-41 with Thermal
Emission Microscopy
60
Fourier
56
4.4
Synthesis of Se-nanoparticles (SNs)
60
4.5
Characterization of SNs
63
4.5.1
Analysis of SNs with X-Ray Diffraction
Spectroscopy
63
4.5.2
Analysis of SNs with Thermal Gravimetric
Analysis
64
4.5.3
Analysis of SNs with Field Emission
Scanning Electron Microscopy
65
4.6
Incorporation of SNs onto MCM-41
66
4.7
Characterization of Se-MCM-41
67
4.7.1
Analysis of Se-MCM-41
Diffraction Spectroscopy.
with
X-Ray
68
4.7.2
Analysis of Se-MCM-41 with Fourier
Transform Infrared.
68
xiv
Analysis of Se-MCM-41 with Thermal
Gravimetric Analysis
69
4.7.4
Analysis of Se-MCM-41 with Field
Emission Scanning Electron Microscopy
71
4.8
Leaching Study of Se-MCM-41
72
4.9
Functionalization of MCM-41 with Amino and
Aldehyde Group and its Characterization
73
4.9.1
Analysis of MCM-41, MCM-A and fMCM-41 with XRD Spectroscopy
75
4.9.2
Analysis of MCM-41, MCM-A and fMCM-41 with FTIR
76
4.10
5
4.7.3
Functionalization of Se-MCM-41 with Aldehyde
Group and its Characterization
78
4.10.1
Analysis of f-Se-MCM-41 using XRD
Spectroscopy
78
4.10.2
Analysis of f-Se-MCM-41 using FTIR
Spectroscopy
80
Optimization of Glucose Oxidase Immobilization onto
MCM-41 Support
82
5.1
Immobilization of Glucose Oxidase (GOx) onto
Functionalized MCM-41 and Se-MCM-41.
82
5.2
Optimization of GOx Immobilization
83
5.2.1
Effect of pH onto GOx Immobilization
83
5.2.2
Effect of Initial Concentration of GOx
enzymes
90
5.3
Immobilization of GOx onto f-MCM-41 and f-SeMCM-41.
93
5.4
Rationale Behind Why GOx-f-Se-MCM-41 is Better
Than GOx-f-MCM-41
95
xv
6
7
Development of Biosensor for Voltammetric Analysis of
Glucose
98
6.1
Electrochemical Behaviour of the GOx-f-MCM-41
and GOx-f-Se-MCM-41.
98
6.1.1
Effect of pH onto GOx-f-MCM-41/CPE
99
6.1.2
Effect of Scan Rate onto GOx-f-MCM41/CPE
106
6.1.3
Analysis of GOx-f-MCM-41 and GOx-f-SeMCM-41 Carbon Paste Electrodes at
Optimum Conditions
109
6.1.4
Analysis of GOx-f-Se-MCM-41/CPE
Under Reduced Oxygen Condition
113
Conclusions
120
7.1
Conclusions
120
7.2
Suggestions and Recommendations
123
REFERENCES
126
APPENDIX
147
xvi
LIST OF TABLES
TABLE NO.
TITLE
PAGE
2.1
Some of the methods reported for the formation of
different types of Se nanoparticles.
17
2.2
Comparison of performance factors of some
commercially available glucose biosensors
30
4.1
Infrared data interpretation for the as-synthesized and
calcined MCM-41.
57
4.2
EDX analyses for MCM-41, SNs and Se-MCM-41
72
4.3
FTIR data interpretation for MCM-41-C, MCM-41-A
and f-MCM-41
77
4.4
Infrared data interpretation for the comparison of SeMCM-41 and f-Se-MCM-41
81
6.1
Comparison of response for voltammetry detection at
pH 6.0 and 7.0.
104
6.2
Effect of scan rate using DPSV voltammetry
108
6.3
Comparison of GOx-f-MCM-41/CPE and GOx-f-SeMCM-41/CPE using cyclic voltammetry at pH 6.0 with
scan rate 10 mV/s.
112
6.4
GOx-f-Se-MCM-41/CPE with the reduced O2 in
graphite as working electrode at pH 6.0 with scan rate
10 mV/s using linear voltammetry.
116
6.5
Comparison of GOx-f-Se-MCM-41/CPE with other
electrodes
118
xvii
LIST OF FIGURES
FIGURE NO.
TITLE
PAGE
2.1
Different types of MCM based on the shape
10
2.2
Structure of monoclinic Se
15
2.3
Structure of trigonal Se
15
2.4
Simple adsorption of enzymes onto surface of support
materials
22
2.5
Entrapment of enzymes in gel, film or membrane
22
2.6
Direct covalent bonding between enzyme and support
material
23
2.7
Cross-linking of enzyme onto support materials
25
2.8
Clinical analysis procedures based on electrochemical
sensors
28
2.9
The principle schematic of (a) first, (b) second and (c)
third generation biosensors
32
4.1
Flow chart of procedures involved in the
functionalization of MCM-41 and it’s incorporation with
SNs
52
4.2
XRD pattern of (a) MCM-41-as and MCM-41-C for
(b) 1 day (c) 2 days and (d) 3 days of calcination time.
54
4.3
Comparison of slow and rapid ramping time during the
calcination process.
55
4.4
Schematic mechanism pathway of the formation of
MCM-41
56
4.5
Infrared spectra of (a) as-synthesized and (b) calcined
MCM-41
56
4.6
TGA-DTG thermogram of MCM-41
58
xviii
4.7
Images of FESEM of MCM-41 at (a) 10 000
59
(b) 15 000 and (c) 25 000 times magnification
4.8
The TEM images of MCM-41 at (a) 25 000 and
60
(b) 100 000 times magnification
4.9
Changes in solution colour during transformation process
of SNs (a) after addition of ascorbic acid and after (b) 1
h (c) 2 h (d) and 3 h of ultrasonication
61
4.10
XRD pattern of SNs
63
4.11
TGA-DTG thermograms of SNs samples
64
4.12
Comparison FESEM image of (a) a-Se and formation of
SNs (b) 24 h aging, (c) using ultrasonication without
aging and (d) using ultrasonication and aging in
combination
66
4.13
Comparison of XRD patterns in the range of 1.5-70° for
(a) Se-MCM-41, (b) SNs and (c) MCM-41
68
4.14
Infrared spectra of (a)MCM-41, (b) SNs and (c) SeMCM-41
69
4.15
TGA thermograms showing comparison of (a) SNs, (b)
MCM-41 and (c) Se-MCM-41
70
4.16
FESEM images of (a) MCM-41 (b) SNs and (c) SeMCM-41
71
4.17
Plot of amount of Se released from Se-MCM-41 vs
leaching period over 24 h
73
4.18
Reaction of MCM-41 with APTES to give MCM-41-A
74
4.19
Reactions involving MCM-41-A with glutaraldehyde to
form f-MCM-41
74
4.20
XRD patterns of (a) MCM-41, (b) MCM-41-A and
75
(c) f-MCM-4
4.21
FTIR spectra of (a) MCM-41(b) MCM-41-A and (c) fMCM-41 in the range of 4000-450 cm-1
76
4.22
Comparison of XRD patterns of (a) Se-MCM-41 and (b)
f-Se-MCM-41 in the range 1.5-10°
79
4.23
Comparison of XRD pattern of (a) Se-MCM-41 and (b)
f-Se-MCM-41 in the range 10-70°
79
4.24
Comparison of XRD patterns of (a) Se-MCM-41 and (b)
f-Se-MCM-41 in the range 1.5-70°
79
xix
4.25
FTIR spectra of (a) Se-MCM-41 and (b) f-Se-MCM-41 in
the range of 4000-450 cm-1
80
5.1
Effects of pH on enzyme specific activity for free,
immobilized enzymes and GOx leaching from the
immobilized supports
84
5.2
Schematic diagram of substrate attachment to the enzyme
active sites of enzyme immobilized onto MCM-41. Not
all the active sites as shown in red circle can be accessed
due to the undesired configuration by which the enzyme
was positioned
86
5.3
Effect of pH on the percentage specific activity of
immobilized enzymes and leaching from the immobilized
supports
88
5.4
Effects of initial concentration on GOx on enzyme
specific activity of free, immobilized enzymes and
leaching from the immobilized supports
90
5.5
Effect of initial concentration on the percentage specific
activity of immobilized enzymes and leaching from the
immobilized supports
92
5.6
Amount of GOx bound onto f-MCM-41 and f-Se-MCM41 at pH 6.0 with 2.0 mg/mL of GOx
94
5.7
Percentage of GOx bound onto f-MCM-41 and f-SeMCM-41 at pH 6.0 with 2.0 mg/mL of initial
concentration of GOx
94
5.8
Hypothetical diagram showing GOx binding with the
aldehyde groups as well as on SNs (red circle) during
GOx immobilization. The red circle at the far right shows
GOx sandwiched in between SN and aldehyde group
which prevents leaching of GOx
96
6.1
DPCSV of effect of pH in the absence of glucose; tacc=
30 s, Eacc= +0.2 V and Ei= +0.7 V. Scan rate = 50 mV/s
100
6.2
DPCSV of comparison in the absence (a,c,e,g) and
presence (b,d,f,h) of glucose based on pH; tacc= 30 s,
Eacc= +0.2 V and Ei= +700mV. Scan rate = 50 mV/s
101
6.3
DPCSV voltammograms of glucose at pH 6.0; tacc= 30 s,
Eacc= +0.2 V and Ei= +0.7 V. Scan rate = 50 mV/s
102
6.4
DPSV voltammograms of glucose at pH 7.0; tacc= 30 s,
Eacc= +0.2 V and Ei= +0.7 V. Scan rate = 50 mV/s
102
xx
6.5
Linear fit of DPCSV responding current and
concentration of glucose at pH 6.0 and 7.0
103
6.6
DPCSV voltammograms of glucose at pH 5.0; tacc= 30 s,
Eacc=+0.2 V and Ei= +0.9 V. Scan rate = 50 mV/s
104
6.7
DPCSV voltammograms of glucose at pH 9.0. ; tacc= 30
s, Eacc=+0.2 V and Ei= +0.9 V. Scan rate = 50 mV/s
104
6.8
Linear fit of DPCSV responding current and
concentration of glucose working at pH 5.0 and 9.0.
105
6.9
DPCSV voltammograms of glucose with scan rate 10
mV/s; tacc= 30 s, Eacc=+0.2 V and Ei= +0.7 V
106
6.10
DPCSV voltammograms of glucose with scan rate 30
mV/s; tacc= 30 s, Eacc= +0.2 V and Ei= +0.7 V
107
6.11
DPCSV voltammograms of glucose with scan rate 50
mV/s; tacc= 30 s, Eacc= +0.2 V and Ei= +0.7 V
107
6.12
Linear fit of DPCSV responding current and
concentration of glucose at scan rate affected by scan rate
108
6.13
Cyclic voltammogram GOx-f-MCM 41/CPE at pH 6.0
with scan rate 10 mV/s; Ei= +0.7 V
110
6.14
Cyclic voltammogram GOx-f-Se-MCM 41/CPE at pH 6.0
with scan rate 10 mV/s; Ei= +700mV
110
6.15
Comparison of responding current of GOx-f-MCM41/CPE and GOx-f-Se-MCM-41/CPE with glucose
concentration using cyclic voltammetry
111
6.16
Linear voltammogram of GOx-f- Se-MCM- 41/CPE when
O2 in graphite pores was removed during heating;
Ei= +0.7 V
114
6.17
Linear fit of responding current and glucose
concentration of GOx-f-Se-MCM 41 with the minimized
O2 in graphite at pH 6.0 with the scan rate of 10 mV/s
116
xxi
LIST OF ABBREVIATIONS
AA
Ascorbic acid
ADA
American Diabetes Association
AOT
Sodium Bis(2-ethylhexyl) Sulfosuccinate
AP
Acetaminophen
APTES
3-aminopropyltriethoxysilane
APTMS
3-aminopropyltrimethoxysilane
a-Se
Amorphous Selenium
Au/GNPs-SBA-15/IO4oxidized-GOD
Gold/Gold Nanoparticles-SBA-15/ Metaperiodate Ion
Oxidized- Glucose Oxidase
Au/H2N-SBA-15/IO4-oxidized-GOD
Gold/Amine-SBA-15/ Metaperiodate Ion OxidizedGlucose Oxidase
Au/SWNT/GOD/PPy
Gold-Single Wall Nanotubes/ Glucose
Oxidase/Polypyrrole
Au/SWNT/GODHRP/PPy
Gold/Single-Walled Carbon Nanotubes/Glucose
Oxidase/Horseradish Peroxidase/Polypyrrole
Au/SWNT/HRPPPy/GOD-PPy
Gold/Single Wall Nanotubes/ Horseradish
Peroxidase/Polypyrrole/Glucose Oxidase/Polypyrrole
BSA
Bovine Serum albumin
CM100B
Bacillus cereus
CTAB
Cetyltrimethylammonium Bromide
CV
Cyclic voltammetry
d100
Plane 100
d110
Plane 110
D200
Plane 200
D210
Plane 210
xxii
DNA
Deoxyribonucleic Acid
DPCSV
Differential Pulse Cathodic Stripping Voltammetry
DTA
Differential Thermal Analysis
DTT
Dithiothreitol
Eacc
Accumulated potential current
EDX
Energy Dispersive X-Ray Spectroscopy
Ei
Initial potential current
Enzymeox
Enzyme oxidized
Enzymered
Enzyme reduced
f- Se-MCM-41
Functionalized-Selenium Nanoparticles-Mobil
Crystalline Materials No. 41
Fe-MCM-41
MCM-41 Modified with Iron.
FESEM
Field Emission Scanning Electron Microscopy
f-MCM-41
Functionalized- Mobil Crystalline Materials No. 41
FSM-16
Folded-Sheet Mesoporous Material
FTIR
Fourier Transform Infrared Spectroscopy
G-CdS
Graphene-Cadmium Sulphur
GNPs
Gold nanoparticles
GOx
Glucose Oxidase
GOx-f- MCM-41/CPE
Glucose Oxidase-Functionalized Mobil Crystalline
Materials No. 41/Carbon Paste Electrode
GOx-f-MCM-41
Glucose Oxidase-Functionalized- Mobil Crystalline
Materials No. 41
GOx-f-Se-MCM-41
Glucose Oxidase-Functionalized Selenium
Nanoparticles- Mobil Crystalline Materials No. 41
GOx-f-Se-MCM-41/CPE
Glucose Oxidase-Functionalized Se-Mobil Crystalline
Materials No. 41/Carbon Paste Electrode
HDP
Hydrodeporphirinization
HDTMA
Hexadecyltrimethylammonium Bromide
HMDS
Hexamethyldisilazane
ICP-MS
Inductively Coupled Plasma Mass Spectroscopy
IDDM
Insulin Dependent Diabetes Mellitus / Juvenile Diabetes
LOD
Correlative of Determination
xxiii
MCF
Mesostructured Cellular Foam
MCM-41
Mobil Crystalline Materials No. 41
MCM-41-A
Amino-Mobil Crystalline Materials No. 41
MCM-41-as
As-synthesized Mobil Crystalline Materials No. 41
MCM-41-C
Calcined Mobil Mobil Crystalline Materials No. 41
MCM-41-C-1d
One day calcined Mobil Crystalline Materials No. 41
MCM-41-C-2d
Two day calcined Mobil Crystalline Materials No. 41
MCM-41-C-3d
Three day calcined Mobil Crystalline Materials No. 41
MCM-48
Mobil Crystalline Materials No. 48
MCM-50
Mobil Crystalline Materials No. 50
MOX
Malaysian Oxygen Berhad
MPTMS
3-mercaptopropyltrimethoxysilane
MWCNTs
Multi-walled carbon nanotubes
NIDDM
Non Insulin Dependent Diabetes Mellitus
PDF
Powder Diffraction File
POD
peroxidase type II from Horseradish
Pt/MCM-41
Platinum Nanoparticles/Mobil Crystalline Materials No.
41
Pt/sulfonated-MWCNTs
Platinum/sulfonated multi-walled carbon nanotubes
PTFE
Polytetraflouroethylene
PtMCWNTs
Platinum multi-walled carbon nanotubes
R2
Correlative of determination
SBA-15
Santa Barbara Amorphous
Se-MCM-41
Selenium Nanoparticles-Mobil Crystalline Materials No.
41
SNs
Selenium Nanoparticles
ß-monoclinic Se
Black crystalline Selenium (Se8 rings)
tacc
Accumulated time
TEM
Transmission Electron Microscopy
TGA
Thermal Gravimetric Analysis
TrxRs
Thioredoxinreductase
t-Se
Trigonal Selenium
xxiv
UA
Uric acid
UV-Vis
Ultraviolet-visible Spectroscopy
XRD
X-ray Diffraction Spectroscopy
α-monoclinic Se
Red crystalline Selenium (Se8 rings)
∆A
Absorbance changes
θ
Theta
Φ
Phi
xxv
LIST OF APPENDICES
APPENDIX
TITLE
PAGE
A1
XRD of MCM-41-as
147
A2
XRD of MCM-41-C-1d
148
A3
XRD of MCM-41-C-2d
148
A4
XRD of MCM-41-C-3d
149
A5
XRD of MCM-41-A
149
A6
XRD of f-MCM-41
150
B1
XRD of SNs in range 10-70°
151
B2
XRD of f-Se-MCM-41 in range 10-70°
152
B3
XRD of Se-MCM-41 in range 1.5-70°
152
B4
XRD of MCM-41 in range 1.5-70°
153
B5
XRD of SNs in range 1.5-70°
153
B6
XRD of Se-MCM-41 in range 1.5-70°
154
B7
XRD of f-Se-MCM-41 in range 1.5-70°
154
C1
FTIR of MCM-41-as
155
C2
FTIR of MCM-41-C
156
C3
FTIR of MCM-41-A
156
C4
FTIR of f-MCM-41
157
D1
FTIR of SNs
158
D2
FTIR of Se-MCM-41
159
D3
FTIR of f-Se-MCM-41
159
E1
EDX of SNs.
160
E2
EDX of Se-MCM-41
161
E3
EDX of Se-MCM-41
162
xxvi
F1
Data of Se release from Se-MCM-41 within 12 h
163
F2
Percentage of Se release from Se-MCM-41
within 12 h
164
G1
Specific activity of immobilization study onto fMCM-41 and f-Se-MCM-41 at different pH
165
G2
Percentage of specific activity of immobilization
study onto f-MCM-41 and f-Se-MCM-41 at
different pH
165
G3
Specific activity of immobilization study onto fMCM-41 and f-Se-MCM-41 at different initial
concentration
166
G4
Percentage of specific activity of immobilization
study onto f-MCM-41 and f-Se-MCM-41 at
different initial concentration
166
G5
Amount of GOx bound onto f-MCM-41 and f-SeMCM-41
166
G6
Percentage of GOx bound onto f-MCM-41 and fSe-MCM-41
167
H1
DPCSV voltammogram at pH 5.0; tacc= 30 s,
Eacc= +0.2 V and Ei= +0.7 V. Scan rate = 50
mV/s
168
H2
DPCSV voltammogram at pH 6.0; tacc= 30 s,
Eacc= +0.2 V and Ei= +0.7 V. Scan rate = 50
mV/s
169
H3
DPCSV voltammogram at pH 7.0; tacc= 30 s,
Eacc= +0.2 V and Ei= +0.7 V. Scan rate = 50
mV/s
169
H4
DPCSV voltammogram at pH 9.0; tacc= 30 s,
Eacc= +0.2 V and Ei= +0.7 V. Scan rate = 50
mV/s
170
H5
DPCSV voltammogram with scan rate 10 mV/s;
pH = 6.0, tacc= 30 s, Eacc= +0.2 V and Ei= +0.7 V
170
H6
Linear voltammogram of GOx-f- Se-MCM41/CPE when O2 in graphite pores was removed
during heating; Ei= +0.7 V
171
H7
Responding current and glucose concentration
effect by pH
171
H8
Responding current and glucose concentration at
172
xxvii
scan rate of 10 mV/s
H9
Responding current and glucose concentration at
scan rate of 30 mV/s
172
H10
Responding current and glucose concentration at
scan rate of 50 mV/s
172
H11
Comparison of responding current of GOx-fMCM-41/CPE and with glucose concentration
using cyclic voltammetry
173
H12
Comparison of responding current of GOx-f-SeMCM-41/CPE with glucose concentration using
cyclic voltammetry
173
H13
Responding current and glucose concentration
of GOx-f-Se-MCM 41 with the minimized O2 in
graphite at pH 6.0 with the scan rate of10 mV/s
174
H14
Linear fit of responding current and glucose
concentration of GOx-f-Se-MCM 41 with the
minimized O2 in graphite at pH 6.0 with the scan
rate of 10 mV/s
174
I1
Standard Curve of Enzyme Concentration
175
J1
Calculation of the amount of specific acivity of
enzyme
176