FIG. 1 C shows the folded shape of the ridges o n another emb o diment of the modified graphite electrode. FIG. I D is a drawing of an embodiment of the modified …

FIG. 2 is a Fourier transform infrared spectrum of graphene oxide.

FIG. 3 is a Raman spectrum of graphite.

FIG. 4 is a Raman spectrum of graphene oxide.

FIG. 5 sho w s a dispersion of graphite.

FIG. 6 shows a dispersion of graphene oxide.

FIG. 7 is a micrograph of a bare graphite electrode at 5,000 x magnif ica tion.

FIG. 8 is a micrograph of a m odif i ed graphite electrode at 5, 000 x magnifi ca tion.

FIG. 9.

FIG. 10 shows. a linear relationship between the peak current and the square root of the scan rate observed in

FIG. 11.

FIG. 12 sho w s a linear relationship between the peak current and the square root of the scan rate observed in

FIG. 13 is an electrochemical im p edance spectrum of a bare graphite electrode in a solution compri s ing 5mM K 3 Fe(CN) 6/K 4 Fe(CN) 6 and 0.1 M KC I.

FIG. 14 is an electrochemical impedance spectrum of a modified graphite electrode in a solution c SVG …

FIG. 15 is a cyclic voltammogram (scan rate: 100 mV s ') at a bare graphite electrode in a solution comprising 1 mM uric acid in a phosphate-buf f ered saline …

FIG. 16 is a cyclic voltammogra m (scan rate: 100 mV s-) at a modified graphite electrode in a solution comprising 1 mM uric acid in a PBS buffer (0.1 M, pH 7.0).

FIG. 17.

FIG. 18 is a plot of the peak currents versus the pH values observed in

FIG. 19 shows a linear relationship between the pH value. and the peak oxidation potential observed in

FIG. 20 shows a r elationship between the current and t he amplitude of the square w ave potential at the modified graphite electrode in a sample comprising 10 …

FIG. 21 shows a relationship between the current and t h e frequency of t he square wave potential a t the modified graphite electrode in a sample comprising 10 …

FIG. 22 shows a relationship be tw een the current and the absorption time at the modified graphite electrode in a sample comprising 10 p M uric acid in a PBS …

FIG. 23). The linear relationship was observed between 0.2 p M and 22 p M uric acid with a regression constant of 0.996. (

FIG. 24 sho w s a linear relationship between the peak current and the concentration of uric acid.

FIG. 25 is a square wave-voltam m ogram o f. 500 p M ascorbic acid in the presence of 50 p M uric acid with square wave voltammet r y parameters: amplitude …

FIG. 27 is a square iv ave. vol t ammogram of 500 p M ascorbic acid in the presence of 50 p M uric acid wit h square wave voltammetry parameters: amplitude 0.0 …

FIG. 28 is a-square wave voltammogram of 500 p M ascorbic acid with square wave voltammetry parameters: amplitude 0.03 V, frequency 50 Hz, and adsorption time …

FIG. 1 C shows the folded shape of the ridges o n another emb o diment of the modified graphite electrode. FIG. I D is a drawing of an embodiment of the modified …

FIG. 2 is a Fourier transform infrared spectrum of graphene oxide.

FIG. 3 is a Raman spectrum of graphite.

FIG. 4 is a Raman spectrum of graphene oxide.

FIG. 5 sho w s a dispersion of graphite.

FIG. 6 shows a dispersion of graphene oxide.

FIG. 7 is a micrograph of a bare graphite electrode at 5,000 x magnif ica tion.

FIG. 8 is a micrograph of a m odif i ed graphite electrode at 5, 000 x magnifi ca tion.

FIG. 9.

FIG. 10 shows. a linear relationship between the peak current and the square root of the scan rate observed in

FIG. 11.

FIG. 12 sho w s a linear relationship between the peak current and the square root of the scan rate observed in

FIG. 13 is an electrochemical im p edance spectrum of a bare graphite electrode in a solution compri s ing 5mM K 3 Fe(CN) 6/K 4 Fe(CN) 6 and 0.1 M KC I.

FIG. 14 is an electrochemical impedance spectrum of a modified graphite electrode in a solution c SVG …

FIG. 15 is a cyclic voltammogram (scan rate: 100 mV s ') at a bare graphite electrode in a solution comprising 1 mM uric acid in a phosphate-buf f ered saline …

FIG. 16 is a cyclic voltammogra m (scan rate: 100 mV s-) at a modified graphite electrode in a solution comprising 1 mM uric acid in a PBS buffer (0.1 M, pH 7.0).

FIG. 17.

FIG. 18 is a plot of the peak currents versus the pH values observed in

FIG. 19 shows a linear relationship between the pH value. and the peak oxidation potential observed in

FIG. 20 shows a r elationship between the current and t he amplitude of the square w ave potential at the modified graphite electrode in a sample comprising 10 …

FIG. 21 shows a relationship between the current and t h e frequency of t he square wave potential a t the modified graphite electrode in a sample comprising 10 …

FIG. 22 shows a relationship be tw een the current and the absorption time at the modified graphite electrode in a sample comprising 10 p M uric acid in a PBS …

FIG. 23). The linear relationship was observed between 0.2 p M and 22 p M uric acid with a regression constant of 0.996. (

FIG. 24 sho w s a linear relationship between the peak current and the concentration of uric acid.

FIG. 25 is a square wave-voltam m ogram o f. 500 p M ascorbic acid in the presence of 50 p M uric acid with square wave voltammet r y parameters: amplitude …

FIG. 27 is a square iv ave. vol t ammogram of 500 p M ascorbic acid in the presence of 50 p M uric acid wit h square wave voltammetry parameters: amplitude 0.0 …

FIG. 28 is a-square wave voltammogram of 500 p M ascorbic acid with square wave voltammetry parameters: amplitude 0.03 V, frequency 50 Hz, and adsorption time …

FIG. 1 C shows the folded shape of the ridges o n another emb o diment of the modified graphite electrode. FIG. I D is a drawing of an embodiment of the modified …

FIG. 2 is a Fourier transform infrared spectrum of graphene oxide.

FIG. 3 is a Raman spectrum of graphite.

FIG. 4 is a Raman spectrum of graphene oxide.

FIG. 5 sho w s a dispersion of graphite.

FIG. 6 shows a dispersion of graphene oxide.

FIG. 7 is a micrograph of a bare graphite electrode at 5,000 x magnif ica tion.

FIG. 8 is a micrograph of a m odif i ed graphite electrode at 5, 000 x magnifi ca tion.

FIG. 9.

FIG. 10 shows. a linear relationship between the peak current and the square root of the scan rate observed in

FIG. 11.

FIG. 12 sho w s a linear relationship between the peak current and the square root of the scan rate observed in

FIG. 13 is an electrochemical im p edance spectrum of a bare graphite electrode in a solution compri s ing 5mM K 3 Fe(CN) 6/K 4 Fe(CN) 6 and 0.1 M KC I.

FIG. 14 is an electrochemical impedance spectrum of a modified graphite electrode in a solution c SVG …

FIG. 15 is a cyclic voltammogram (scan rate: 100 mV s ') at a bare graphite electrode in a solution comprising 1 mM uric acid in a phosphate-buf f ered saline …

FIG. 16 is a cyclic voltammogra m (scan rate: 100 mV s-) at a modified graphite electrode in a solution comprising 1 mM uric acid in a PBS buffer (0.1 M, pH 7.0).

FIG. 17.

FIG. 18 is a plot of the peak currents versus the pH values observed in

FIG. 19 shows a linear relationship between the pH value. and the peak oxidation potential observed in

FIG. 20 shows a r elationship between the current and t he amplitude of the square w ave potential at the modified graphite electrode in a sample comprising 10 …

FIG. 21 shows a relationship between the current and t h e frequency of t he square wave potential a t the modified graphite electrode in a sample comprising 10 …

FIG. 22 shows a relationship be tw een the current and the absorption time at the modified graphite electrode in a sample comprising 10 p M uric acid in a PBS …

FIG. 23). The linear relationship was observed between 0.2 p M and 22 p M uric acid with a regression constant of 0.996. (

FIG. 24 sho w s a linear relationship between the peak current and the concentration of uric acid.

FIG. 25 is a square wave-voltam m ogram o f. 500 p M ascorbic acid in the presence of 50 p M uric acid with square wave voltammet r y parameters: amplitude …

FIG. 27 is a square iv ave. vol t ammogram of 500 p M ascorbic acid in the presence of 50 p M uric acid wit h square wave voltammetry parameters: amplitude 0.0 …

FIG. 28 is a-square wave voltammogram of 500 p M ascorbic acid with square wave voltammetry parameters: amplitude 0.03 V, frequency 50 Hz, and adsorption time …

FIG. 1 C shows the folded shape of the ridges o n another emb o diment of the modified graphite electrode. FIG. I D is a drawing of an embodiment of the modified …

FIG. 2 is a Fourier transform infrared spectrum of graphene oxide.

FIG. 3 is a Raman spectrum of graphite.

FIG. 4 is a Raman spectrum of graphene oxide.

FIG. 5 sho w s a dispersion of graphite.

FIG. 6 shows a dispersion of graphene oxide.

FIG. 7 is a micrograph of a bare graphite electrode at 5,000 x magnif ica tion.

FIG. 8 is a micrograph of a m odif i ed graphite electrode at 5, 000 x magnifi ca tion.

FIG. 9.

FIG. 10 shows. a linear relationship between the peak current and the square root of the scan rate observed in

FIG. 11.

FIG. 12 sho w s a linear relationship between the peak current and the square root of the scan rate observed in

FIG. 13 is an electrochemical im p edance spectrum of a bare graphite electrode in a solution compri s ing 5mM K 3 Fe(CN) 6/K 4 Fe(CN) 6 and 0.1 M KC I.

FIG. 14 is an electrochemical impedance spectrum of a modified graphite electrode in a solution c SVG …

FIG. 15 is a cyclic voltammogram (scan rate: 100 mV s ') at a bare graphite electrode in a solution comprising 1 mM uric acid in a phosphate-buf f ered saline …

FIG. 16 is a cyclic voltammogra m (scan rate: 100 mV s-) at a modified graphite electrode in a solution comprising 1 mM uric acid in a PBS buffer (0.1 M, pH 7.0).

FIG. 17.

FIG. 18 is a plot of the peak currents versus the pH values observed in

FIG. 19 shows a linear relationship between the pH value. and the peak oxidation potential observed in

FIG. 20 shows a r elationship between the current and t he amplitude of the square w ave potential at the modified graphite electrode in a sample comprising 10 …

FIG. 21 shows a relationship between the current and t h e frequency of t he square wave potential a t the modified graphite electrode in a sample comprising 10 …

FIG. 22 shows a relationship be tw een the current and the absorption time at the modified graphite electrode in a sample comprising 10 p M uric acid in a PBS …

FIG. 23). The linear relationship was observed between 0.2 p M and 22 p M uric acid with a regression constant of 0.996. (

FIG. 24 sho w s a linear relationship between the peak current and the concentration of uric acid.

FIG. 25 is a square wave-voltam m ogram o f. 500 p M ascorbic acid in the presence of 50 p M uric acid with square wave voltammet r y parameters: amplitude …

FIG. 27 is a square iv ave. vol t ammogram of 500 p M ascorbic acid in the presence of 50 p M uric acid wit h square wave voltammetry parameters: amplitude 0.0 …

FIG. 28 is a-square wave voltammogram of 500 p M ascorbic acid with square wave voltammetry parameters: amplitude 0.03 V, frequency 50 Hz, and adsorption time …