The detection method and detecting electrode material of a kind of electrochemistry of uric acid in urine
Technical field
The present invention relates to the detection method and detecting electrode material of a kind of electrochemistry of the uric acid in urine, belong to detection skill
Art field.
Background technology
Uric acid height is likely to cause goat, therefore to prevent goat as the first to be appointed to an office.For universal, gout is due to purine
Metabolic disorder causes blood uric acid to increase and cause one group of disease of tissue damage, and cause is that prolonged uric acid is excessive caused,
The problems such as uric acid deposits at joint, kidney.Lesion often invades the tissue such as joint, kidney, and age of onset is more more than 40, illness rate
Increase with the age, the ratio between men and women is 50:1, most artificial post menopausal female woman of woman's venereal disease, Chang Chun, autumn morbidity.Therefore,
For the high patient of blood uric acid, should particularly pay attention to.
At present, the determination method of uric acid has fluorescence method, high performance liquid chromatography, enzyme method and electrochemical method etc..
These detection methods cut both ways, and chromatography is most basic detection method, and good separating effect, mobile phase is simple, easy to operate,
Quickly, but the sample handling processes of multistep are needed;Spectroscopic methodology is easily disturbed by other chromophories present in sample;Though enzyme method
So selectivity is good but expensive, limits its use scope;Electrochemical method have it is easy to operate, it is of low cost, it is sensitive
The features such as degree is high, and detection limit is low.
But a problem is existing for electrochemical method:The electrode of preparation is had a great influence be subject to preparation parameter, holds
Easily there is the detection performance of electrode in batch there are larger difference, influenced detection accuracy.
The content of the invention
The purpose of the present invention is:A kind of electrochemical detection method for being used to detect uric acid in urine is provided, this method is main
It is that make use of the surface of graphene passing through hydroxyl modification, allows it to be easier to be grafted cyano-containing group, then pass through electro-deposition
The electrode material for having preferable catalytic effect to uric acid is prepared in its surface deposited catalyst in mode, the materials application in
When being detected in urine, have to uric acid and preferably detect stability, the opposite mark between the electrode detection result of multiple batches of preparation
Quasi- deviation is smaller.
More specifically technical solution is:
A kind of preparation method of uric acid electrochemical detection electrode material, includes the following steps:
1st step, graphene oxide is prepared by Hummers methods;
2nd step, the reduction of graphene oxide:The graphene oxide that 1st step obtains is dispersed in water, obtains 4~8mg/mL's
Graphene oxide dispersion, takes 50~60mL graphene oxide dispersions, and 70~80wt% of 30~50 μ L is slowly added dropwise thereto
Hydrazine hydrate solution, then reacted at 85~90 DEG C, product is filtered out, is washed, it is dry after, obtain graphene;
3rd step, the acid of graphene are modified:By weight, 12~20 parts of graphene and sour 25~30 parts of mixed liquor are mixed
Close, then the heating reflux reaction under ultrasonication, the sour mixed liquor refers to by volume 3~4.5:The concentrated sulfuric acid of 1 compounding
With the mixed liquor of concentrated nitric acid, after reaction, product is filtered out, then is washed with deionized, is dry, sour carbon modified is obtained and receives
Mitron;
4th step, the acid of graphene are modified:By weight, by sour 20~25 parts of modified graphene with being modified mixed liquor 32~40
Part mixing, is warming up to 65~70 DEG C and is reacted, the modification mixed liquor is the hydrogen peroxide by the concentrated sulfuric acid and 20~30wt%
Solution mixes, and after reaction, product is filtered out, then is washed with deionized, is dry, obtains carboxy-modified graphite
Alkene;
5th step, the hydroxyl modification of graphene:By weight, by 4~8 parts carboxy-modified of graphene and 30~42 parts of SOCl2
Under the conditions of 60~65 DEG C carry out 8~12h of back flow reaction, after reaction, solids is filtered out, be redispersed in ethylene glycol 35~
In 40 parts, in 105~114 DEG C of 22~24h of back flow reaction, after reaction, solids is filtered out, is washed with deionized, does
It is dry, obtain the graphene of surface hydroxyl modification;
6th step, graphene surface it is cyanalation:By the graphene dispersion of surface hydroxyl modification in 130~140 parts of ethanol,
Add formula(I)10~15 parts shown of cyano group oxosilane modifying agent, stirring reaction, is centrifuged solids, then according to
After secondary use ethanol, water washing, the cyanalation graphene in surface is obtained;
(I);
Wherein, R1, R2, R3 are separately selected from the straight chain containing 1~10 carbon atom or branched alkyl, more preferably
It is that R1, R2 and R3 are ethyl or isopropyl;
7th step, the preparation of modified electrode:Glass-carbon electrode is polished, is polished to minute surface, successively with ultra-pure water, absolute ethyl alcohol
After washing, dried up with nitrogen;The cyanalation graphene dispersion in surface is made into the dispersion liquid of 1~5mg/mL in ultra-pure water, will
Electrode is infiltrated in dispersion liquid, naturally dry after taking-up, is infiltrated-is dried step and be repeated 3 times, obtains modified electrode;
8th step, the deposition of surface catalytic layer:By the modified electrode of above-mentioned preparation be placed in the NaCl containing 1~3mol/L, 20~
The K of 35mmol3[Fe(CN)6], the Bi (NO of 20~25mmol3)3, 25~40mmol Ce (NO3)3Electrodeposit liquid in, with 2.0
The constant potential voltage of~3.0V is deposited, and is dried after taking-up, is obtained electrode material.
In 2nd step, the reaction time is 1~3h.
In 3rd step, the concentration of the concentrated sulfuric acid is 75~85wt%;The concentration of the concentrated sulfuric acid is 50~
60wt%;The time being heated to reflux is 2~4h.
In 4th step, the concentration of the concentrated sulfuric acid is 75~85wt%, and the reaction time is 1~4h.
In 8th step, the time of electro-deposition is 60~80s.
The electrochemical method of uric acid, includes the following steps in a kind of detection urine:
S1:Uric acid standard items are taken, are configured to the standard solution of various concentrations scope, it is molten using phosphate buffer solution adjustment criteria
The pH of liquid is in 5.0~5.5 scopes;
S2:The electrode material of above-mentioned preparation is taken, cyclic voltammetry scan is carried out by being placed in standard solution, it is big to obtain peak current
It is small;
S3:Standard curve is drawn according to peak current size and concentration of standard solution;
S4:Sample is detected, uric acid content is calculated by standard curve.
In the S2 steps, the concentration range of the standard solution of various concentrations scope is 2.0 × 10-9~6.0 × 10- 4mol/L。
In the S2 steps, the voltage range of cyclic voltammetry scan is -0.8~-0.05V.
Beneficial effect
Mainly it make use of provided by the present invention for the electrochemical detection method of uric acid in detection urine by the surface of graphene
By hydroxyl modification, its is set to be easier to be grafted cyano-containing group, then in its surface deposited catalyst by way of electro-deposition,
The electrode material that there is preferable catalytic effect to uric acid is prepared, when which detects in urine, has to uric acid
Preferable detection stability, the relative standard deviation between the electrode detection result of multiple batches of preparation are smaller.
Brief description of the drawings
Fig. 1 is the cyclic voltammetry curve when electrode material prepared in embodiment 3 carries out standard solution detection.
Fig. 2 is the standard curve of the electrode material prepared in embodiment 3.
Embodiment
In following embodiment, the step of Hummers methods prepare graphene oxide, is:1)By 1g native graphites, dense
H2SO4、H3PO4Three is placed in three-necked flask, and dense H2SO4With H3PO4Volume ratio be 9: 1, and by several times add 6g permanganic acid
Potassium, stirs 1h in ice-water bath.2)Temperature rises to 50 DEG C, insulation reaction 12h.3)Products therefrom is poured into frozen water, side stirring
Side adds appropriate hydrogen peroxide, until solution colour is changed into golden yellow, then filters, and use HCl(Volume fraction is 5%)And distillation
Product is washed till pH value close to 7 by water.Finally, gained graphite oxide is dispersed in water, ultrasonic 8h, is placed in vacuum drying chamber and does
It is dry spare.
Embodiment 1
Uric acid electrochemical detection electrode material step:
1st step, graphene oxide is prepared by Hummers methods;
2nd step, the reduction of graphene oxide:The graphene oxide that 1st step obtains is dispersed in water, obtains the oxidation of 4mg/mL
Graphene dispersing solution, takes 50mL graphene oxide dispersions, and the hydrazine hydrate solution of the 70wt% of 30 μ L is slowly added dropwise thereto, then
1h is reacted at 85 DEG C, product is filtered out, is washed, after drying, obtains graphene;
3rd step, the acid of graphene are modified:By weight, 12 parts of graphene is mixed with sour 25 parts of mixed liquor, then super
The lower heating reflux reaction 2h of sound effect, the sour mixed liquor refer to by volume 3:The 75wt% concentrated sulfuric acids and 50wt% of 1 compounding
The mixed liquor of concentrated nitric acid, after reaction, product is filtered out, then is washed with deionized, is dry, obtains sour modified carbon nano tube
Pipe;
4th step, the acid of graphene are modified:By weight, sour 20 parts of modified graphene is mixed with modified 32 parts of mixed liquor, risen
Temperature carries out reaction 1h to 65 DEG C, the modification mixed liquor be by the mixing of the hydrogenperoxide steam generator of the 75wt% concentrated sulfuric acids and 20wt% and
Into, after reaction, product is filtered out, then be washed with deionized, be dry, obtain carboxy-modified graphene;
5th step, the hydroxyl modification of graphene:By weight, by 4 parts carboxy-modified of graphene and 30 parts of SOCl2At 60 DEG C
Under the conditions of carry out back flow reaction 8h, after reaction, solids is filtered out, is redispersed in 35 parts of ethylene glycol, in 105 DEG C reflux
22h is reacted, after reaction, solids is filtered out, is washed with deionized, is dry, obtaining the graphene of surface hydroxyl modification;
6th step, graphene surface it is cyanalation:By the graphene dispersion of surface hydroxyl modification in 130 parts of ethanol, add
10 parts of (2- cyanoethyls) triethoxysilane, stirring reaction, is centrifuged solids, then successively with ethanol, water washing
Afterwards, the cyanalation graphene in surface is obtained;
7th step, the preparation of modified electrode:Glass-carbon electrode is polished, is polished to minute surface, successively with ultra-pure water, absolute ethyl alcohol
After washing, dried up with nitrogen;The cyanalation graphene dispersion in surface is made into the dispersion liquid of 1mg/mL in ultra-pure water, by electrode
It is infiltrated in dispersion liquid, naturally dry after taking-up, infiltrates-dry step and be repeated 3 times, obtain modified electrode;
8th step, the deposition of surface catalytic layer:The modified electrode of above-mentioned preparation is placed in NaCl, 20mmol containing 1mol/L
K3[Fe(CN)6], the Bi (NO of 20mmol3)3, 25mmol Ce (NO3)3Electrodeposit liquid in, with the constant potential voltage of 2.0V into
Row deposition 60s, dries after taking-up, obtains electrode material.
Embodiment 2
Uric acid electrochemical detection electrode material step:
1st step, graphene oxide is prepared by Hummers methods;
2nd step, the reduction of graphene oxide:The graphene oxide that 1st step obtains is dispersed in water, obtains the oxidation of 8mg/mL
Graphene dispersing solution, takes 60mL graphene oxide dispersions, and the hydrazine hydrate solution of the 80wt% of 50 μ L is slowly added dropwise thereto, then
3h is reacted at 90 DEG C, product is filtered out, is washed, after drying, obtains graphene;
3rd step, the acid of graphene are modified:By weight, 20 parts of graphene is mixed with sour 30 parts of mixed liquor, then super
The lower heating reflux reaction 4h of sound effect, the sour mixed liquor refer to by volume 4.5:1 compounding the 85wt% concentrated sulfuric acids and
The mixed liquor of 60wt% concentrated nitric acids, after reaction, product is filtered out, then is washed with deionized, is dry, obtains sour modification
Carbon nanotubes;
4th step, the acid of graphene are modified:By weight, sour 25 parts of modified graphene is mixed with modified 40 parts of mixed liquor, risen
Temperature carries out reaction 4h to 70 DEG C, the modification mixed liquor be by the mixing of the hydrogenperoxide steam generator of the 85wt% concentrated sulfuric acids and 30wt% and
Into, after reaction, product is filtered out, then be washed with deionized, be dry, obtain carboxy-modified graphene;
5th step, the hydroxyl modification of graphene:By weight, by 8 parts carboxy-modified of graphene and 42 parts of SOCl2At 65 DEG C
Under the conditions of carry out back flow reaction 12h, after reaction, solids is filtered out, is redispersed in 40 parts of ethylene glycol, in 114 DEG C return
Stream reaction 24h, after reaction, solids is filtered out, and is washed with deionized, is dry, obtaining the graphite of surface hydroxyl modification
Alkene;
6th step, graphene surface it is cyanalation:By the graphene dispersion of surface hydroxyl modification in 140 parts of ethanol, add
15 parts of (2- cyanoethyls) triethoxysilane, stirring reaction, is centrifuged solids, then successively with ethanol, water washing
Afterwards, the cyanalation graphene in surface is obtained;
7th step, the preparation of modified electrode:Glass-carbon electrode is polished, is polished to minute surface, successively with ultra-pure water, absolute ethyl alcohol
After washing, dried up with nitrogen;The cyanalation graphene dispersion in surface is made into the dispersion liquid of 5mg/mL in ultra-pure water, by electrode
It is infiltrated in dispersion liquid, naturally dry after taking-up, infiltrates-dry step and be repeated 3 times, obtain modified electrode;
8th step, the deposition of surface catalytic layer:The modified electrode of above-mentioned preparation is placed in NaCl, 35mmol containing 3mol/L
K3[Fe(CN)6], the Bi (NO of 25mmol3)3, 40mmol Ce (NO3)3Electrodeposit liquid in, with the constant potential voltage of 3.0V into
Row deposition 80s, dries after taking-up, obtains electrode material.
Embodiment 3
Uric acid electrochemical detection electrode material step:
1st step, graphene oxide is prepared by Hummers methods;
2nd step, the reduction of graphene oxide:The graphene oxide that 1st step obtains is dispersed in water, obtains the oxidation of 5mg/mL
Graphene dispersing solution, takes 55mL graphene oxide dispersions, and the hydrazine hydrate solution of the 75wt% of 40 μ L is slowly added dropwise thereto, then
2h is reacted at 88 DEG C, product is filtered out, is washed, after drying, obtains graphene;
3rd step, the acid of graphene are modified:By weight, 15 parts of graphene is mixed with sour 28 parts of mixed liquor, then super
The lower heating reflux reaction 3h of sound effect, the sour mixed liquor refer to by volume 4:The 80wt% concentrated sulfuric acids and 55wt% of 1 compounding
The mixed liquor of concentrated nitric acid, after reaction, product is filtered out, then is washed with deionized, is dry, obtains sour modified carbon nano tube
Pipe;
4th step, the acid of graphene are modified:By weight, sour 22 parts of modified graphene is mixed with modified 35 parts of mixed liquor, risen
Warm to 680 DEG C carry out reaction 2h, and the modification mixed liquor is mixed by the hydrogenperoxide steam generator of the 80wt% concentrated sulfuric acids and 25wt%
Form, after reaction, product is filtered out, then be washed with deionized, be dry, obtain carboxy-modified graphene;
5th step, the hydroxyl modification of graphene:By weight, by 5 parts carboxy-modified of graphene and 35 parts of SOCl2At 62 DEG C
Under the conditions of carry out back flow reaction 10h, after reaction, solids is filtered out, is redispersed in 38 parts of ethylene glycol, in 109 DEG C return
Stream reaction 23h, after reaction, solids is filtered out, and is washed with deionized, is dry, obtaining the graphite of surface hydroxyl modification
Alkene;
6th step, graphene surface it is cyanalation:By the graphene dispersion of surface hydroxyl modification in 135 parts of ethanol, add
12 parts of (2- cyanoethyls) triethoxysilane, stirring reaction, is centrifuged solids, then successively with ethanol, water washing
Afterwards, the cyanalation graphene in surface is obtained;
7th step, the preparation of modified electrode:Glass-carbon electrode is polished, is polished to minute surface, successively with ultra-pure water, absolute ethyl alcohol
After washing, dried up with nitrogen;The cyanalation graphene dispersion in surface is made into the dispersion liquid of 3mg/mL in ultra-pure water, by electrode
It is infiltrated in dispersion liquid, naturally dry after taking-up, infiltrates-dry step and be repeated 3 times, obtain modified electrode;
8th step, the deposition of surface catalytic layer:The modified electrode of above-mentioned preparation is placed in NaCl, 25mmol containing 2mol/L
K3[Fe(CN)6], the Bi (NO of 22mmol3)3, 35mmol Ce (NO3)3Electrodeposit liquid in, with the constant potential voltage of 2.5V into
Row deposition 70s, dries after taking-up, obtains electrode material.
Reference examples 1
Difference with embodiment 3 is:Cyano group modification is not carried out to the surface of graphene.
Uric acid electrochemical detection electrode material step:
1st step, graphene oxide is prepared by Hummers methods;
2nd step, the reduction of graphene oxide:The graphene oxide that 1st step obtains is dispersed in water, obtains the oxidation of 5mg/mL
Graphene dispersing solution, takes 55mL graphene oxide dispersions, and the hydrazine hydrate solution of the 75wt% of 40 μ L is slowly added dropwise thereto, then
2h is reacted at 88 DEG C, product is filtered out, is washed, after drying, obtains graphene;
3rd step, the acid of graphene are modified:By weight, 15 parts of graphene is mixed with sour 28 parts of mixed liquor, then super
The lower heating reflux reaction 3h of sound effect, the sour mixed liquor refer to by volume 4:The 80wt% concentrated sulfuric acids and 55wt% of 1 compounding
The mixed liquor of concentrated nitric acid, after reaction, product is filtered out, then is washed with deionized, is dry, obtains sour modified carbon nano tube
Pipe;
4th step, the acid of graphene are modified:By weight, sour 22 parts of modified graphene is mixed with modified 35 parts of mixed liquor, risen
Warm to 680 DEG C carry out reaction 2h, and the modification mixed liquor is mixed by the hydrogenperoxide steam generator of the 80wt% concentrated sulfuric acids and 25wt%
Form, after reaction, product is filtered out, then be washed with deionized, be dry, obtain carboxy-modified graphene;
5th step, the hydroxyl modification of graphene:By weight, by 5 parts carboxy-modified of graphene and 35 parts of SOCl2At 62 DEG C
Under the conditions of carry out back flow reaction 10h, after reaction, solids is filtered out, is redispersed in 38 parts of ethylene glycol, in 109 DEG C return
Stream reaction 23h, after reaction, solids is filtered out, and is washed with deionized, is dry, obtaining the graphite of surface hydroxyl modification
Alkene;
6th step, the preparation of modified electrode:Glass-carbon electrode is polished, is polished to minute surface, successively with ultra-pure water, absolute ethyl alcohol
After washing, dried up with nitrogen;The graphene dispersion of surface hydroxyl modification is made into the dispersion liquid of 3mg/mL in ultra-pure water, by electricity
Pole is infiltrated in dispersion liquid, naturally dry after taking-up, is infiltrated-is dried step and be repeated 3 times, obtains modified electrode;
7th step, the deposition of surface catalytic layer:The modified electrode of above-mentioned preparation is placed in NaCl, 25mmol containing 2mol/L
K3[Fe(CN)6], the Bi (NO of 22mmol3)3, 35mmol Ce (NO3)3Electrodeposit liquid in, with the constant potential voltage of 2.5V into
Row deposition 70s, dries after taking-up, obtains electrode material.
Reference examples 2
Difference with embodiment 3 is:Before cyano group modification is carried out, hydroxylating processing is not carried out to its surface.
Uric acid electrochemical detection electrode material step:
1st step, graphene oxide is prepared by Hummers methods;
2nd step, the reduction of graphene oxide:The graphene oxide that 1st step obtains is dispersed in water, obtains the oxidation of 5mg/mL
Graphene dispersing solution, takes 55mL graphene oxide dispersions, and the hydrazine hydrate solution of the 75wt% of 40 μ L is slowly added dropwise thereto, then
2h is reacted at 88 DEG C, product is filtered out, is washed, after drying, obtains graphene;
3rd step, the acid of graphene are modified:By weight, 15 parts of graphene is mixed with sour 28 parts of mixed liquor, then super
The lower heating reflux reaction 3h of sound effect, the sour mixed liquor refer to by volume 4:The 80wt% concentrated sulfuric acids and 55wt% of 1 compounding
The mixed liquor of concentrated nitric acid, after reaction, product is filtered out, then is washed with deionized, is dry, obtains sour modified carbon nano tube
Pipe;
4th step, the acid of graphene are modified:By weight, sour 22 parts of modified graphene is mixed with modified 35 parts of mixed liquor, risen
Warm to 680 DEG C carry out reaction 2h, and the modification mixed liquor is mixed by the hydrogenperoxide steam generator of the 80wt% concentrated sulfuric acids and 25wt%
Form, after reaction, product is filtered out, then be washed with deionized, be dry, obtain carboxy-modified graphene;
5th step, graphene surface it is cyanalation:By carboxy-modified graphene dispersion in 135 parts of ethanol, (2- cyanogen is added
Ethyl) 12 parts of triethoxysilane, stirring reaction, is centrifuged solids, then successively with ethanol, after water washing,
Obtain the cyanalation graphene in surface;
6th step, the preparation of modified electrode:Glass-carbon electrode is polished, is polished to minute surface, successively with ultra-pure water, absolute ethyl alcohol
After washing, dried up with nitrogen;The cyanalation graphene dispersion in surface is made into the dispersion liquid of 3mg/mL in ultra-pure water, by electrode
It is infiltrated in dispersion liquid, naturally dry after taking-up, infiltrates-dry step and be repeated 3 times, obtain modified electrode;
7th step, the deposition of surface catalytic layer:The modified electrode of above-mentioned preparation is placed in NaCl, 25mmol containing 2mol/L
K3[Fe(CN)6], the Bi (NO of 22mmol3)3, 35mmol Ce (NO3)3Electrodeposit liquid in, with the constant potential voltage of 2.5V into
Row deposition 70s, dries after taking-up, obtains electrode material.
Reference examples 3
Difference with embodiment 3 is:Bismuth nitrate is not added in the deposition of surface catalytic layer.
Uric acid electrochemical detection electrode material step:
1st step, graphene oxide is prepared by Hummers methods;
2nd step, the reduction of graphene oxide:The graphene oxide that 1st step obtains is dispersed in water, obtains the oxidation of 5mg/mL
Graphene dispersing solution, takes 55mL graphene oxide dispersions, and the hydrazine hydrate solution of the 75wt% of 40 μ L is slowly added dropwise thereto, then
2h is reacted at 88 DEG C, product is filtered out, is washed, after drying, obtains graphene;
3rd step, the acid of graphene are modified:By weight, 15 parts of graphene is mixed with sour 28 parts of mixed liquor, then super
The lower heating reflux reaction 3h of sound effect, the sour mixed liquor refer to by volume 4:The 80wt% concentrated sulfuric acids and 55wt% of 1 compounding
The mixed liquor of concentrated nitric acid, after reaction, product is filtered out, then is washed with deionized, is dry, obtains sour modified carbon nano tube
Pipe;
4th step, the acid of graphene are modified:By weight, sour 22 parts of modified graphene is mixed with modified 35 parts of mixed liquor, risen
Warm to 680 DEG C carry out reaction 2h, and the modification mixed liquor is mixed by the hydrogenperoxide steam generator of the 80wt% concentrated sulfuric acids and 25wt%
Form, after reaction, product is filtered out, then be washed with deionized, be dry, obtain carboxy-modified graphene;
5th step, the hydroxyl modification of graphene:By weight, by 5 parts carboxy-modified of graphene and 35 parts of SOCl2At 62 DEG C
Under the conditions of carry out back flow reaction 10h, after reaction, solids is filtered out, is redispersed in 38 parts of ethylene glycol, in 109 DEG C return
Stream reaction 23h, after reaction, solids is filtered out, and is washed with deionized, is dry, obtaining the graphite of surface hydroxyl modification
Alkene;
6th step, graphene surface it is cyanalation:By the graphene dispersion of surface hydroxyl modification in 135 parts of ethanol, add
12 parts of (2- cyanoethyls) triethoxysilane, stirring reaction, is centrifuged solids, then successively with ethanol, water washing
Afterwards, the cyanalation graphene in surface is obtained;
7th step, the preparation of modified electrode:Glass-carbon electrode is polished, is polished to minute surface, successively with ultra-pure water, absolute ethyl alcohol
After washing, dried up with nitrogen;The cyanalation graphene dispersion in surface is made into the dispersion liquid of 3mg/mL in ultra-pure water, by electrode
It is infiltrated in dispersion liquid, naturally dry after taking-up, infiltrates-dry step and be repeated 3 times, obtain modified electrode;
8th step, the deposition of surface catalytic layer:The modified electrode of above-mentioned preparation is placed in NaCl, 25mmol containing 2mol/L
K3[Fe(CN)6], the Ce (NO of 35mmol3)3Electrodeposit liquid in, deposition 70s is carried out with the constant potential voltage of 2.5V, after taking-up
Dry, obtain electrode material.
To the methodology validation of uric acid detection
1st, it is repeated
Prepare 1.0 × 10-6The uric acid aqueous solution of mol/L, while pH to 5.2 is adjusted with phosphate buffer solution, according to above-mentioned side
Method prepares electrode, and each embodiment and reference examples respectively prepare 6, swept with cyclic voltammetry in the range of -0.8~-0.05V
Retouch, record maximum current value, the average value and relative standard deviation of the electric current of each group are as shown in the table:
|
Embodiment 1 |
Embodiment 2 |
Embodiment 3 |
Reference examples 1 |
Reference examples 2 |
Reference examples 3 |
Current average × 10-5A |
0.021 |
0.025 |
0.024 |
0.015 |
0.018 |
0.012 |
Electric current relative standard deviation RSD % |
2.5 |
2.9 |
1.4 |
12.5 |
10.6 |
3.2 |
As can be seen from the above table, electrode of the invention has the repetition of preferable electrode material when carrying out Electrochemical Detection
Property, when be repeated several times experiment, the deviation of current average is small.
2nd, it is linear
The concentration range for preparing the standard solution of various concentrations scope is 1.0 × 10-8、5.0×10-6、1.0×10-5、2.0×
10-5、4.0×10-5The uric acid solution of mol/L, is respectively adopted above-mentioned electrode material and carries out cyclic voltammetry scanning, investigate dense
Degree and the linear relationship of size of current.Embodiment 3 prepare electrode it is linear as shown in Figure 2.
R squares of the regression equation and regression coefficient of each group are as follows(The unit of Y is × 10-5A):
|
Regression equation |
R2 |
Embodiment 1 |
Y=1952.1X+0.1152 |
0.9947 |
Embodiment 2 |
Y=2142.8X-0.0865 |
0.9925 |
Embodiment 3 |
Y=2536.8X+0.1069 |
0.9969 |
Reference examples 1 |
Y=3252.1X+0.1125 |
0.9234 |
Reference examples 2 |
Y=1622.3X+0.2427 |
0.9527 |
Reference examples 3 |
Y=3051.2X-0.3215 |
0.9912 |
As can be seen from the above table, electrode material provided by the invention is 1.0 × 10-8~6.0 × 10-4It is linear in the range of mol/L
Well, the material in reference examples 1 does not carry out material due to cyanomodified so that there is surface catalysis when electrode is detected
The problem of material load is uneven, linear regression coeffficient is bad;Due to not carrying out hydroxyl modification to graphene in reference examples 2, make
Cyanomodified dose bad in its surface grafting, it is bad to also result in the load of material surface catalysis material, imitates linear regression
Fruit is bad.
3rd, detection limit
Prepare 2.0 × 10-9The uric acid aqueous solution of mol/L, while pH to 5.2 is adjusted with phosphate buffer solution, according to above-mentioned side
Method prepares electrode, and each embodiment and reference examples respectively prepare 6, swept with cyclic voltammetry in the range of -0.8~-0.05V
Retouch, record maximum current value, the average value and relative standard deviation of the electric current of each group are as shown in the table:
|
Embodiment 1 |
Embodiment 2 |
Embodiment 3 |
Reference examples 1 |
Reference examples 2 |
Reference examples 3 |
Current average × 10-8A |
0.045 |
0.049 |
0.045 |
Do not detect |
0.018 |
Do not detect |
Electric current relative standard deviation RSD % |
7.5 |
8.2 |
7.2 |
Do not detect |
20.4 |
Do not detect |
As can be seen from the table, electrode of the invention can be detected under extremely low uric acid concentration, low with detection limit
Advantage.Due to not using cyanomodified electrode material in reference examples 1, cause its surface catalysis electrical conduction effect bad, fail to examine
Go out phase induced current;Due to not adding bismuth nitrate in reference examples 3, cause catalytic effect bad, can also make detection limit excessive.
4th, sample recovery rate
True urine specimen is taken, is separately added into 1.0 × 10-6mol/L、5.0×10-6mol/L、1.0×10-5The uric acid of mol/L,
And pH to 5.2 is adjusted with phosphate buffer solution at the same time, electrode is prepared according to the above method, each embodiment and reference examples are respectively prepared
6, be scanned with cyclic voltammetry in the range of -0.8~-0.05V, according to standard curve calculate sample recovery rate, every group
Sample recovery rate it is as follows:
1.0×10-6Sample recovery rate under mol/L concentration
|
1.0×10-6mol/L |
5.0×10-6mol/L |
1.0×10-5mol/L |
Embodiment 1 |
101.2% |
101.5% |
99.8% |
Embodiment 2 |
99.2% |
98.5% |
102.1% |
Embodiment 3 |
98.5% |
101.3 |
100.5% |
Reference examples 1 |
47.8% |
62.2% |
67.2% |
Reference examples 2 |
65.2% |
75.4% |
79.9% |
Reference examples 3 |
85.6% |
81.5% |
86.2% |
As can be seen from the table, when carrying out sample recovery rate verification, the scope of the rate of recovery exists electrode material provided by the invention
In the range of 95%~105%, there is preferable detection result.Since electrode material is without cyanomodified, electronics biography in reference examples 1
Defeated and surface catalysis material load effect is bad, and it is bad to result in detection result;Due to not carrying out graphene in reference examples 2
Surface hydroxylation is modified, and can not be grafted enough cyanomodified dose, the problem of detection result is bad also occurs;Reference examples 3 by
In not adding bismuth nitrate, cause catalytic effect bad, can not detect enough uric acid in sample, it is inclined to result in sample recovery rate
It is low.