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The Ratios of Ruthenium Hexacyanoferrate to Carbon Powders on the Sensitivity of Detection of Hydrogen Peroxide for the Carbon Paste Electrode Modified with Ruthenium
Hexacyanoferrate and Its Application to Glucose Biosensor
Kuo-Hsiang Liao (廖國翔) , Ting-Li Lin (林庭立) , Hau Lin (林浩)
Department of Chemical and Materials Engineering, Southern Taiwan University
南台科技大學化學工程與材料工程系
ABSTRACT：
A study was conducted to use the ruthenium hexacyanoferrate(Ⅱ) to modify carbon paste electrode which was used as the working electrode to detect the responding current of reduction of hydrogen peroxide in the phosphate buffer
solution( pH = 7.4 )and the sensitivity of detection of hydrogen peroxide was determined from the responding current and consequently, the concentration of the glucose could be determined. The results showed that the responding current for
the carbon paste electrode modified with the ruthenium hexacyanoferrate(Ⅱ) was elevated significantly. At 30℃, -0.2V operating potential, and in 0.05 M phosphate buffer solution (PBS), the TB (Time Base) graphs for the carbon paste
electrode modified with different ratios of ruthenium hexacyanoferrate to carbon powders were plotted to evaluate the effect of the ratios of ruthenium hexacyanoferrate to carbon powders on the responding current of detection of hydrogen
peroxide. At 30℃ , -0.2V operating potential, and in 0.05 M phosphate buffer solution( pH = 7.4 ), when the carbon paste electrode was modified with the ruthenium hexacyanoferrate(Ⅱ) [ruthenium hexacyanoferrate(Ⅱ) : carbon powders = 3 :
7 ( weight ratio )] , the detection limit was 0.02 mM C6H12O6 , the linear range was 0.02~2.56 mM C6H12O6 , R2=0.999, and the sensitivity was 4.11 µA/cm2．mM C6H12O6.
INTRODUCTION ：
RESULTS AND DISCUSSION ：
(
)
A study was conducted to use the ruthenium hexacyanoferrate(Ⅱ) to modify the carbon
paste electrode which was used as the working electrodes to detect the responding current of
reduction of hydrogen peroxide in the phosphate buffer solution(PBS) and then the
concentration of hydrogen peroxide could be obtained from the responding current and
consequently, the concentration of the glucose could be determined. At 30℃, -0.2V operating
potential, and in 0.05 M phosphate buffer solution (PBS), the TB (Time Base) graphs for the
carbon paste electrode modified with different ratios of ruthenium hexacyanoferrate to carbon
powders were plotted to evaluate the effect of the ratios of ruthenium hexacyanoferrate to
carbon powders on the responding current of detection of hydrogen peroxide. After the
optimum ratio of ruthenium hexacyanoferrate to carbon powders was determined, the carbon
paste electrode was used to determine the sensitivity of detection of glucose.
EXPERIMENTAL SECTION：
( )
Preparation of Ruthenium
Hexacyanoferrate ：
30 mM Potassium
Hexacyanoferrate 5 mL
Drying
Centrifuging
Repeat Centrifuging
Ruthenium
Hexacyanoferrate
Powders
Three Times
Fig 1. CV graphs for (A) carbon paste electrode
modified with ruthenium hexacyanoferrate( the
range of scanning potential: -0.8～+0.8 V) (B)
unmodified carbon paste electrode( the range of
scanning potential: -0.6～+0.6 V)
Fig. 2 TB graphs of the carbon paste electrodes with
different ratios of ruthenium hexacyanoferrate(Ⅱ) to
carbon powders; the ruthenium hexacyanoferrate(Ⅱ) to
carbon powders are〔(A) 0:10(unmodified carbon paste
electrode) (B) 1:9 (C) 2:8 (D) 3:7 (E) 4:6 (F) 5:5 ; 15μL of
100mM H2O2 is injected per 100 seconds
3 mM Ruthenium Chloride
Hydrate 50 mL
Preparation of Working Electrode：
1. Take one section of 7 cm electric wire with 0.05 cm inside diameter. After depriving the coating 0.5
cm length from both ends, the nake-ended wire was washed, dried and ready for use.
7 cm
0.05 cm
0.5 cm
2. Then the ruthenium hexacyanoferrate(Ⅱ) powders, carbon powders and carbon paste were
mixed with the appropriate ratio.
adding carbon paste
ruthenium
hexacyanoferrate
Fig. 3 The calibration curves of different ratios of
ruthenium hexacyanoferrate(Ⅱ) to carbon powders
〔(A) 0:10(unmodified carbon paste electrode) (B) 1:9
(C) 2:8 (D) 3:7 (E) 4:6 (F) 5:5〕
Table 1 The sensitivities and R2 values for
different weight ratios of ruthenium
hexacyanoferrate(Ⅱ) to carbon powders
( appropriate ratio )
carbon
powder
A
powder
appropriate A
powder
8μL
1μL
3. After the mixing was complete, the mixture was evenly coated on the nake-ended electric wire
and dried in the oven and then we obtained the carbon paste electrode.
2μL
16μL
4μL
4. After the above mentioned carbon paste electrode was dried, the 3μL
glucose oxidase solution( 3mg of glucose oxidase was dissolved in 200μL PBS
buffer solution ) was put onto the surface of electrode and the electrode was
dried at room temperature. Then 5μL of 1% Nafion solution(in 95% alcohol)
was dropped onto the electrode evenly and after the electrode was dried at
room temperature, we obtained the glucose biosensor.
Fig.4 The TB graphs of glucose biosensor for detection of glucose
(ruthenium hexacyanoferrate(Ⅱ) : carbon powders = 3 : 7); At 30
℃; the operating potential = –0.2 V; in 0.1 M KCl of 5 mL 0.05 M
PBS buffer solution ( pH=7.4 ); stirring rate =600 rpm; 1μL , 2μL ,
4μL , 8μL and16μL of 100mM glucose are injected at 100 seconds,
200 seconds, 300 seconds, 400 seconds ,and 500 seconds respectively
Fig. 5 The TB graphs of glucose biosensor for detection of
glucose (ruthenium hexacyanoferrate(Ⅱ) : carbon powders
= 3 : 7); At 30 ℃; the operating potential = –0.2 V; in 0.1 M
KCl of 5 mL 0.05 M PBS buffer solution ( pH=7.4 ); stirring
rate=600 rpm; 16μL of 100mM glucose is injected per 100
seconds
CONCLUSIONS ：The results showed that the responding current for the carbon paste electrode
modified with the ruthenium hexacyanoferrate(Ⅱ) was elevated significantly. The optimum weight
ratio for ruthenium hexacyanoferrate(Ⅱ) : carbon powders was 3 : 7 . For the glucose biosensor, at
30℃ , -0.2V operating potential, and in 0.05 M PBS buffer solution( pH = 7.4 ), when the carbon paste
electrode was modified with the ruthenium hexacyanoferrate(Ⅱ) [ruthenium hexacyanoferrate(Ⅱ) :
carbon powders = 3 : 7 ( weight ratio )] , the detection limit was 0.02 mM C6H12O6 ; the linear range
was 0.02 ~ 2.56 mM C6H12O6 ; R2 = 0.999 and the sensitivity was 4.11 μA/cm2 mM C6H12O6 .
Nafion
Glucose Oxidase
PVC cover
REFERENCES ：
1. S. J. Updike and G. P. Hicks, “The Enzyme Electrode,” Nature, Vol. 214, 986 (1967)
2. R. Garjonyte and A. Malinauskas, “Glucose Biosensor Based on Glucose Oxidase Immobilized in Electropolymerized
Polypyrrole and Poly(o-Phenylenediamine) Films on a Prussian Blue-Modified Electrode,” Sensors and Actuaors B, Vol.
63, 122, (2000).
3. M. A. Kim and W. -Y. Lee, “Amperometric Phenol Biosensor Based on Sol-Gel Silicate/Nafion Composite Film,”
Analytica Chimica Acta, Vol. 479, 143 (2003).
4. S. Singh, A. Chaubey, and B. D. Malhotra, “Amperometric Cholesterol Biosensor Based on Immobilized Cholesterol
Esterase and Cholesterol Oxidase on Conducting Polypyrrole Films,” Analytica Chimica Acta, Vol. 502, 229 (2004).