CN105277601A

CN105277601A - Method and special electrochemical detector for electrochemical detection of baicalein

Info

Publication number: CN105277601A
Application number: CN201510700268.0A
Authority: CN
Inventors: 姚媛媛; 张小梅; 励娜; 梁旭明; 陈一龙; 杨大坚; 师萱
Original assignee: Chongqing Academy of Chinese Materia Medica
Current assignee: China Academy of Chinese Medical Sciences CACMS; Chongqing Academy of Chinese Materia Medica
Priority date: 2015-11-13
Filing date: 2015-11-13
Publication date: 2016-01-27

Abstract

The invention provides a rapid and selective detection method of baicalein. A traditional Chinese medicine material or Chinese patent medicine preparation is crushed into powder, stirring extraction is performed with absolute ethyl alcohol for 12 h, and a test solution is obtained after filtration and volume metering. A configured beta-CD-Pd-GR/GCE nano-composite modified electrode electrochemical sensor is used for detecting and analyzing the test solution to determine the content of the baicalein. A preparation method of the electrochemical sensor for the baicalein is low in preparation cost, simple in technology and easy to operate, the electrochemical sensor prepared with the method can be used for detecting the baicalein successfully and is high in sensitivity and good in stability.

Description

A kind of baicalein electrochemical detection method and Special electric chemical detector thereof

Technical field

The present invention relates to a kind of chemical detection method, relate to a kind of baicalein electrochemical detection method and Special electric chemical detector thereof in particular.

Technical background

β-CD (cyclodextrine, β-cyclodextrin), the cyclic oligosaccharide be made up of seven glucose units, be be easy to get most in cyclodextrin, price is minimum, use maximum one, its hydrophobic internal cavities and water sucting surface composition annular, this structure can be used as coaggregation sites makes various guest molecule assemble in the cavities.Meanwhile, β-CD has water-soluble and environment friendly, can improve the water-soluble of functional material and stability.Pd-GR (Graphene/palladium composite nano materials), combine the large superior function of Graphene specific surface area and the good catalytic performance of Pd nano particle, utilize the advantage of β-CD and Pd-GR, prepare the galvanochemistry biography device that a kind of simple, practical, efficient, sensitive, accurate, inexpensive fast selective measures baicalein, and attempt baicalein content in the application actual sample root of large-flowered skullcap.

Baicalein (5,6,7-trihydroxyflavone), being baikal skullcap root principle active component, is one of flavone compound that content is the highest.Monomer is yellow prism-shaped crystallization, is dissolved in ethanol, methyl alcohol, ether, acetone, ethyl acetate, hot glacial acetic acid, is slightly soluble in chloroform and nitrobenzene, water-soluble hardly.Baicalein has multiple efficacies, as antibacterial, antiviral, antiallergy, antithrombotic, anticoagulation, anticancer, inflammation-inhibiting reacts, protect the liver, cholagogic, diuresis, scavenging free radicals etc., there is good clinical value, be mainly used in respiratory tract infection, acute tonsillitis, pharyngitis, chronic obstructive pulmonary disease, catarrhal jaundice, acute/chronic gastroenteritis and bacillary dysentery, pyelonephritis etc. at present, and show good curative effect.Therefore, develop a kind of quick, easy, efficient method baicalein determination method and there is important theoretical and practical significance.

Now set up the assay method of multiple baicalein, mainly contain gas chromatography, liquid chromatography, liquid chromatography and mass spectrometry, gas chromatography and mass spectrometry, Capillary Electrophoresis etc., these methods have good sensitivity, but, often need higher technology content, numerous and diverse preprocessing process and price comparison is expensive.By comparison, electrochemical sensor have cost low, save time, prepare simple, easy and simple to handle, highly sensitive, selectivity is good, can realize the advantage such as microminiaturization and on-line checkingi, in flavonoids drug test, had extensive concern.Guo etc. have successfully prepared 2,6-dimethyl-β-CD functionalization graphene modified electrode is used for synchronous detection flavone compound isoquercitrin and baicalein, and be applied to the content analysis (Z.G.Liu of two materials in actual sample human serum, A.Zhang, Y.J.Guo, C.Dong, BiosensorsandBioelectronics58 (2014) 242 – 248).Chen etc. utilize molecularly imprinted polymer SBA-15 successfully to determine baicalein content in rat tissue.Up to the present, the mensuration that the electrochemical sensor utilizing β-CD and Pd-GR premium properties to prepare is applied to baicalein content in the root of large-flowered skullcap not yet has report.

Summary of the invention

For solving the problem, the invention provides a kind of baicalein fast selective detection method, Chinese crude drug or Chinese patent medicine preparation being ground into powder, extracting 12h by absolute ethyl alcohol and stirring, filtration is fixed molten obtains test liquid.Use the nano combined modified electrode electrochemical sensor of configuration β-CD – Pd-GR/GCE to carry out detection to test liquid to analyze, determine the content of baicalein.

The Special electric chemical sensor that baicalein fast selective detects; In the three-electrode system of described sensor, take saturated calomel electrode as contrast electrode, platinum filament is to electrode, and the working electrode of described sensor is: the nano combined modified electrode of β-CD – Pd-GR/GCE being modified preparation by supermolecule β-CD and functionalization graphene Pd-GR.

The preparation method of the nano combined modified electrode of described β-CD – Pd-GR comprises the following steps:

1) by 1.016g potassium persulfate (K ₂s ₂o ₈), 1.1136g phosphorus pentoxide (P ₂o ₅), the dense H of 4.8mL ₂sO ₄mixing is placed in 50mL beaker, then adds 0.6g dag, water-bath 4.5h at 85 DEG C.The atrament obtained is called pre-oxidation thing, washs after its suction filtration with redistilled water, dry.Next day, in pre-oxidation thing, slowly add the dense H of 24mL being less than under the ice bath of 20 DEG C and stirring condition ₂sO ₄with the potassium permanganate (KMnO after 3.0g grinding ₄).Then stirred in water bath 2h potpourri being placed on 35 DEG C shows taupe to solution, dropwise adds the dilution of 50mL water, under agitation adds the H of the intermediate water 140mL and 30% of heat half an hour ₂o ₂2mL is glassy yellow to solution.Washing and filtering to solution arrives neutral, and suction filtration, vacuum drying 12h at 60 DEG C, prepares GO (graphene oxide).

2) getting the pulverous GO of 32mg (graphene oxide) adds in the beaker filling 60mL water, and ultrasonic 45min makes it fully disperse.Then this homogeneous dispersion liquid is placed in round-bottomed flask and adds 110mL water, add the hydrazine of 55 μ L85wt.% and the ammonia of 385 μ L25wt.% under stirring, Keep agitation 1h under 95 DEG C of oil bath conditions.By gained suspending liquid suction filtration, washing is also dry under vacuo, prepares GR (reduced graphene).

3) be that the palladium bichloride of 1g/mL and 32g graphite oxide powder add in the beaker filling 60mL water by 150 μ L concentration, ultrasonic 2h makes it fully disperse.Then dispersion liquid is placed in round-bottomed flask and adds 110mL, regulate pH ﹥ 13 with NaOH, add the hydrazine hydrate of 4mL85%.Mixed liquor is placed in 95 DEG C of oil bath 4h, adds 7.5mL water after taking-up, at room temperature stir 48h.Dry at suction filtration, washing, 40 DEG C, vacuum, obtain Pd-GR.

4) mass ratio 2% β-CD is dissolved into refining DMF, ultrasonic 1h, in solution, adds Pd-GR powder, make Pd-GR concentration be 0.25mgmL ^-1, ultrasonic mix after, obtain β-CD – Pd-GR dispersion liquid.

5) get 5 μ L β-CD – Pd-GR dispersant liquid drops and be coated onto clean glass-carbon electrode (GCE) surface of polishing, 60 DEG C of dryings, the obtained nano combined modified electrode of β-CD – Pd-GR.

Advantageous Effects of the present invention is: baicalein galvanochemistry of the present invention passes the preparation method of device, its preparation cost is cheap, technique simple, it is simple and easy to operate, the electrochemical sensor using this method to prepare successfully can not only detect baicalein, but also has highly sensitive, good stability.

Accompanying drawing explanation

The preparation of the nano combined modified electrode of Fig. 1 β-CD – Pd-GR/GCE, the extraction of baicalein and Electrochemical Detection process flow diagram thereof in baikal skullcap root;

The nano combined modified electrode of Fig. 2 β-CD – Pd-GR/GCE detects the linear diagram of baicalein.

Embodiment

The preparation of the nano combined modified electrode of embodiment 1 β-CD – Pd-GR/GCE

Step 1: by 1.016g potassium persulfate (K ₂s ₂o ₈), 1.1136g phosphorus pentoxide (P ₂o ₅), the dense H of 4.8mL ₂sO ₄mixing is placed in 50mL beaker, then adds 0.6g dag, water-bath 4.5h at 85 DEG C.The atrament obtained is called pre-oxidation thing, washs after its suction filtration with redistilled water, dry.Next day, in pre-oxidation thing, slowly add the dense H of 24mL being less than under the ice bath of 20 DEG C and stirring condition ₂sO ₄with the potassium permanganate (KMnO after 3.0g grinding ₄).Then stirred in water bath 2h potpourri being placed on 35 DEG C shows taupe to solution, dropwise adds the dilution of 50mL water, under agitation adds the H of the intermediate water 140mL and 30% of heat half an hour ₂o ₂2mL is glassy yellow to solution.Washing and filtering to solution arrives neutral, and suction filtration, vacuum drying 12h at 60 DEG C, prepares GO (graphene oxide).

Step 2: get the pulverous GO of 32mg (graphene oxide) and add in the beaker filling 60mL water, ultrasonic 45min makes it fully disperse.Then this homogeneous dispersion liquid is placed in round-bottomed flask and adds 110mL water, add the hydrazine of 55 μ L85wt.% and the ammonia of 385 μ L25wt.% under stirring, Keep agitation 1h under 95 DEG C of oil bath conditions.By gained suspending liquid suction filtration, washing is also dry under vacuo, prepares GR (reduced graphene).

Step 3: be that palladium bichloride and the 32gGR powder of 1g/mL adds in the beaker filling 60mL water by 150 μ L concentration, ultrasonic 2h makes it fully disperse.Then dispersion liquid is placed in round-bottomed flask and adds 110mL, regulate pH ﹥ 13 with NaOH, add the hydrazine hydrate of 4mL85%.Mixed liquor is placed in 95 DEG C of oil bath 4h, adds 7.5mL water after taking-up, at room temperature stir 48h.Dry at suction filtration, washing, 40 DEG C, vacuum, obtain Pd-GR.

Step 4: mass ratio 2% β-CD is dissolved into refining DMF, ultrasonic 1h, adds Pd-GR powder in solution, makes Pd-GR concentration be 0.25mgmL ^-1, ultrasonic mix after, obtain β-CD – Pd-GR dispersion liquid.

Step 5: get 5 μ L β-CD – Pd-GR dispersant liquid drops and be coated onto clean glass-carbon electrode (GCE) surface of polishing, 60 DEG C of dryings, the obtained nano combined modified electrode of β-CD – Pd-GR, as shown in Figure 1.

The investigation of the nano combined modified electrode of embodiment 2 β-CD – Pd-GR/GCE

Step 1: take saturated calomel electrode as contrast electrode, platinum filament is to electrode, the nano combined modified electrode of β-CD – Pd-GR/GCE of preparation is working electrode, be connected to electrochemical workstation, the baicalein of variable concentrations is added in the phosphate buffered solution of pH7.0, by differential pulse voltammetry, Electrochemical Detection is carried out to baicalein, the relation of foundation peak current and baicalein concentration, drawing curve, peak current and baicalein concentration are good linear relationship (as shown in Figure 2), and the equation of linear regression of matching is:

I _p.1(μA)＝6.99+0.449C(μm)，R＝0.991

I _p.2(μA)＝11.43+0.102C(μm)，R＝0.990

Lowest detection is limited to 0.03 μ Μ (S/N=3).

Step 2: under optimum experiment condition, assesses the selectivity of β-CD – Pd-GR/GCE by interference experiment, to alkannin, citric acid, oxalic acid, ascorbic acid, glucose, lysine, urea, sweet mellow wine and various zwitterion as Na ⁺, K ⁺, Mg ²⁺, Ca ²⁺, Ni ²⁺, Zr ²⁺, Cu ²⁺, Al ³⁺, SO ₄ ^2-, PO ₄ ^3-, NO ₃ ^2-, CO ₂ ^2-have stronger antijamming capability Deng all, peak current change is less than 5% (97.4 – 104.2%), illustrates that modified electrode has good selectivity.Continued to detect 30 times to baicalein by same electrode, relative standard deviation is 2.42%.Identical preparation method is adopted under identical conditions, prepare 5 β-CD – Pd-GR/GCE modified electrodes respectively, respectively baicalein is detected, the relative standard deviation detected separately for five times is 3.82%, electrode is deposited in 4 DEG C of refrigerators, every other day detect once, after one month, strength of current still keeps initial 89.6%, illustrates that modified electrode has good stability and repeatability.

Embodiment 2 baicalein fast selective detects the application of Special electric chemical sensor

The root of large-flowered skullcap that medicinal material market is bought is cleaned up, dries, accurately take 1.0g, use mortar pulverize; Get commercially available baicalein chlorine capsule (the accurate font size of traditional Chinese medicines: Z22025570), use mortar pulverize; Above-mentioned two groups of samples are placed in conical flask, add the anhydrous dissolving of 30mL, Keep agitation 12h, filter constant volume in 50mL.Use standard addition method, β-CD – the Pd-GR/GCE of preparation is used for baicalein assay in the actual sample root of large-flowered skullcap, carry out detection to the analysis sample containing variable concentrations baicalein to analyze: its recovery is between 99.2% to 101.8%, relative standard deviation, lower than 2.5%, shows that the sensor built does not need to carry out to detection of drugs the determination of trace that purifying can be applied to baicalein in actual sample efficiently, accurately.

Claims

1. a baicalein fast selective detection method, is characterized in that: prepare Chinese crude drug or Chinese patent medicine preparation test liquid; Use the nano combined modified electrode electrochemical sensor of configuration β-CD – Pd-GR/GCE to carry out detection to test liquid to analyze, determine the content of baicalein.

2. baicalein fast selective detection method according to claim 1, it is characterized in that: the preparation method of described Chinese crude drug or Chinese patent medicine preparation test liquid is: Chinese crude drug or Chinese patent medicine preparation are ground into powder, extract 12h by absolute ethyl alcohol and stirring, filtration is fixed molten obtains test liquid.

3. the Special electric chemical sensor of a baicalein fast selective detection; In the three-electrode system of described sensor, take saturated calomel electrode as contrast electrode, platinum filament is to electrode, it is characterized in that: the working electrode of described sensor is: the nano combined modified electrode of β-CD – Pd-GR/GCE being modified preparation by supermolecule β-CD and functionalization graphene Pd-GR.

4. the Special electric chemical sensor of baicalein fast selective detection according to claim 3; It is characterized in that: the nano combined modified electrode of described β-CD – Pd-GR/GCE is: obtained by β-CD and Pd-GR drop-coating.

5. the Special electric chemical sensor of baicalein fast selective detection according to claim 5; It is characterized in that: the preparation method of the nano combined modified electrode of described β-CD – Pd-GR comprises the following steps:

1) mass ratio 2% β-CD is dissolved into refining DMF, ultrasonic 1h, in solution, adds Pd-GR powder, make Pd-GR concentration be 0.25mgmL ^-1, ultrasonic mix after, obtain β-CD – Pd-GR dispersion liquid;

2) get 5 μ L β-CD – Pd-GR dispersant liquid drops and be coated onto clean glass-carbon electrode (GCE) surface of polishing, 60 DEG C of dryings, the obtained nano combined modified electrode of β-CD – Pd-GR.

6. the Special electric chemical sensor of baicalein fast selective detection according to claim 5; It is characterized in that: the preparation method of described Pd-GR is: be that palladium bichloride and the 32gGR powder of 1g/mL adds in the beaker filling 60mL water by 150 μ L concentration, ultrasonic 2h makes it fully disperse;

Then dispersion liquid is placed in round-bottomed flask and adds 110mL, regulate pH ﹥ 13 with NaOH, add the hydrazine hydrate of 4mL85%;

Mixed liquor is placed in 95 DEG C of oil bath 4h, adds 7.5mL water after taking-up, at room temperature stir 48h;

Dry at suction filtration, washing, 40 DEG C, vacuum, obtain Pd-GR.