CN102735769A - Ion chromatography-carbon nanotube-modified electrode electrochemical detection analysis system - Google Patents
Ion chromatography-carbon nanotube-modified electrode electrochemical detection analysis system Download PDFInfo
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- CN102735769A CN102735769A CN2012102050171A CN201210205017A CN102735769A CN 102735769 A CN102735769 A CN 102735769A CN 2012102050171 A CN2012102050171 A CN 2012102050171A CN 201210205017 A CN201210205017 A CN 201210205017A CN 102735769 A CN102735769 A CN 102735769A
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- methotrexate
- electrode
- folic acid
- modified electrode
- mtx
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Abstract
The invention relates to an application system of chemical apparatus analysis, and especially relates to an ion chromatography-carbon nanotube-modified electrode electrochemical detection analysis system used for simultaneously detecting folic acid and methotrexate. The invention relates to an ion chromatography-carbon nanotube-modified electrode electrochemical detection analysis system. According to the invention, the carbon nanotubes are positively charged through covalent modification, and are absorbed on the surface of bare glass carbon electrode, such that novel carbon nanotube membrane-modified electrode is formed. The modified electrode is adopted as a working electrode, such that methotrexate and folic acid in anion states can be easily absorbed. Compared to bare glass carbon electrode, electrocatalytic oxidation of methotrexate and folic acid are greatly promoted. According to the invention, the modified electrode is applied in combination with ion chromatography in an ion chromatography electrochemical detector, such that methotrexate and folic acid rapid separation and detection are realized. Therefore, a problem that separation cannot be realized by using merely electroanalysis, and defects of low sensitivity, high interference and complicated operation of other detection methods, are overcome. The system is suitable for detections of low-concentration methotrexate and folic acid in complex substrate biological samples.
Description
Technical field
The present invention relates to the using system that a kind of chemical apparatuses is analyzed.Particularly relate to the chromatography of ions-carbon nano tube modified electrode Electrochemical Detection analytic system that detects folic acid and methotrexate (MTX) simultaneously.
Background technology
(Flolic acid, FA) chemistry " pteroylglutamic acid " by name belongs to a kind of of B family water soluble vitamin to folic acid, participates in a lot of important reactions in the body, is the important substance of the activity of earning a bare living.It extensively is present in the green vegetables, is human body cell growth and divides one of necessary material, and it is synthetic and promote nitrogen base acid synthetic protein mainly to participate in nucleic acid, also participates in the synthetic of important compound such as haemoglobin, choline, creatine and adrenaline.(Methotrexate MTX) is the folic acid homolog to methotrexate (MTX), is mainly used in treatment tumour, rheumatism.In the rheumatoid disease clinical treatment, the patient took folic acid again in 24 hours and detoxifies after taking methotrexate (MTX).Therefore, detect acid of body fluid middle period and methotrexate (MTX) simultaneously diagnosis, treatment and the prognosis of disease are judged to have important value.The common analytical approach of folic acid and methotrexate (MTX) is high performance liquid chromatography, electrochemical process, capillary electrophoresis etc.High performance liquid chromatography separates, and analyzes as detecting device with ultraviolet, fluorescence and mass spectrum etc. usually, and ultraviolet sensitivity is low and interference is big, the difficult detection of satisfying low concentration folic acid and methotrexate (MTX) in the biological sample such as serum; Fluoroscopic examination needs through the derivatization step usually, and is comparatively loaded down with trivial details; And mass spectrum institute use instrument costs an arm and a leg, and operating cost is high.Methotrexate (MTX) and folic acid structural similarity all have electroactively, and to the existing report of the detection respectively of methotrexate (MTX) and folic acid, but because the electrochemical oxidation current potential is close, therefore simple electricity analytical method detects when can't satisfy both based on various modified electrodes.CNT is owing to have a huge specific surface area, and good electrical conductivity and can promote electron transport is widely used in the research of modified electrode, and carbon nano tube modified electrode can make the oxidation overpotential reduce, and electrochemical signals strengthens greatly.Separation through chromatography of ions and coupling based on the Electrochemical Detection of carbon nano tube modified electrode can realize that the high sensitivity of methotrexate (MTX) and folic acid detects simultaneously.Up to now, do not see with chromatography of ions-carbon nano tube modified electrode electrochemical assay and measure the report of folic acid and methotrexate (MTX) simultaneously.
Summary of the invention
The present invention is the pin improvements over the prior art just, provide a kind of chromatography of ions-carbon nano tube modified electrode galvanochemistry efficiently to detect the analytic system of methotrexate (MTX) and folic acid simultaneously, and technical scheme of the present invention is following:
The present invention is a kind of chromatography of ions-carbon nano tube modified electrode Electrochemical Detection analytic system; CNT is positively charged through covalent modification, is adsorbed on naked glass-carbon electrode surface, forms novel carbon nano-tube film modified electrode; With this modified electrode as working electrode; More be prone to methotrexate (MTX) and folic acid that absorption is the negative ion attitude, naked relatively glass-carbon electrode greatly promotes the catalytic oxidation of methotrexate (MTX) and folic acid.
System of the present invention may be used on can realizing separating fast of methotrexate (MTX) and folic acid with the chromatography of ions coupling in the electrochemical detector and detecting, and detects when being fit in the complicated substrate biological species sample low concentration methotrexate (MTX) and folic acid.
CNT carries out behind the covalent modification positively charged; Be adsorbed on electronegative naked glass-carbon electrode surface securely through electrostatic interaction; Form the firm carbon nano-tube film of one deck, with the functionalized carbon nano-tube modified glassy carbon as working electrode, through cyclic voltammetry (Cyclic voltammetry; CV) in each pH phosphate buffer solution, methotrexate (MTX) and folic acid are measured optimization and select current potential; This modified electrode is applied in the electrochemical detector of chromatography of ions and the chromatography of ions coupling, has realized rapidly and efficiently detecting simultaneously of methotrexate (MTX) and folic acid, and be successfully applied to the detection of blood and urine sample.
The present invention has following advantage and effect:
1. to utilize CNT to have a particle diameter little in the present invention, and specific surface area is big, is prone to modify, and electric conductivity is good; Can promote the transmission of electronics, carbon nano tube modified electrode can make the reaction overpotential reduce advantages such as electrochemical signals enhancing greatly; With positively charged behind the CNT covalent modification, the glass-carbon electrode surface electrostatic effect with electronegative makes more stable carbon nano-tube film modified electrode; Compare with naked glass-carbon electrode, this carbon nano tube modified electrode activity increases greatly, because the CNT positively charged; Therefore adsorb methotrexate (MTX) and the folic acid that is anionic form more easily, promote the catalytic oxidation of methotrexate (MTX) and folic acid, greatly improved sensitivity.
2. the present invention is applied to this modified electrode in the electrochemical detector of chromatography of ions and the chromatography of ions coupling; Realized the quick separation detection of methotrexate (MTX) and folic acid; Both solved the problem that simple electroanalysis can't separate; It is low to have overcome other detection method sensitivity again, and interference reaches shortcomings such as complex operation by force, the detection of low concentration methotrexate (MTX) and folic acid in the suitable complicated substrate biological sample.
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Description of drawings
Fig. 1 is that naked glass-carbon electrode and carbon nano tube modified electrode are as working electrode cyclic voltammetric comparison diagram to the methotrexate (MTX) catalytic oxidation in pH=5 buffer solution;
Fig. 2 is that naked glass-carbon electrode and carbon nano tube modified electrode are as working electrode cyclic voltammetric comparison diagram to the folic acid catalytic oxidation in pH=5 buffer solution;
Fig. 3 is for adopting chromatography of ions-Electrochemical Detection analytic system, respectively with naked glass-carbon electrode and carbon nano tube modified electrode standard model (folic acid, methotrexate (MTX)) the contrast colors spectrogram as working electrode;
Fig. 4 is the reality and mark-on sample (blood) chromatogram of chromatography of ions-carbon nano tube modified electrode Electrochemical Detection analytic system;
Fig. 5 is the reality and mark-on sample (urine) chromatogram of chromatography of ions-carbon nano tube modified electrode Electrochemical Detection analytic system.
Be labeled as among Fig. 1:
The naked glass-carbon electrode of 1-; The 2-carbon nano tube modified electrode; 3-methotrexate (MTX) (10 mgL
-1)
Be labeled as among Fig. 2:
The naked glass-carbon electrode of 1-; The 2-carbon nano tube modified electrode; 3-folic acid (10 mgL
-1)
Be labeled as among Fig. 3:
The naked glass-carbon electrode of 1-; The 2-carbon nano tube modified electrode; 3-methotrexate (MTX) (2 mgL
-1); 4-folic acid (2 mgL
-1)
Be labeled as among Fig. 4:
The blank blood sample of 1-; 2-mark-on blood sample; 3-methotrexate (MTX) (mark-on 0.5 mgL
-1); 4-folic acid (mark-on 0.5 mgL
-1)
Be labeled as among Fig. 5:
The blank urine sample of 1-; 2-mark-on urine sample; 3-methotrexate (MTX) (mark-on 0.5 mgL
-1); 4-folic acid (mark-on 0.5 mgL
-1)
Specific embodiments
Do further bright specifically below in conjunction with Figure of description to the present invention:
Naked glass-carbon electrode is used 0.3 μ m, α-Al of 0.05 μ m successively
2O
3Polishing, and successively clean 5 min at absolute ethyl alcohol and deionized water for ultrasonic, Ag/AgCl (saturated KCl solution) is a contrast electrode, platinum electrode is to electrode.At first with MWNTs at dense HNO
3Reflux is 8 hours in the solution, then the gained black suspension is filtered, and fully washs with deionized water, at last the dry carboxylic carbon nano-tube that gets under infrared lamp.Accurately take by weighing 50 mg carboxylic carbon nano-tubes, join 5.00 mL thionyl chlorides, nitrogen protection with tetrahydrofuran washing and vacuum drying, obtains the CNT of chloride at 45 ℃ of following reflux 24 h.40 mg chloride CNTs and 3 ml ethylenediamines are blended in 60 ℃ of reflux 24 h; With the remaining ethylenediamine of methanol wash; Obtain aminated CNT after the drying, last aminated CNT and iodomethane reaction obtain positively charged quaternized CNT.Get the quaternized CNT of 10 mg to 10 ml deionized water for ultrasonic ripples, 20 min that vibrate; Make it be dispersed into dark solution; Get 5 these solution of μ L and be instilled on the glass-carbon electrode and launch naturally to pave, drying promptly obtains the carbon nano tube modified glass-carbon electrode of modifying under infrared lamp.
Fig. 1 is for adopting cyclic voltammetry; Use naked glass-carbon electrode and prepared carbon nano tube modified electrode as working electrode respectively; Ag/AgCl (saturated KCl solution) is a contrast electrode; Platinum electrode is to electrode, and (wherein methotrexate (MTX) concentration is 10 mgL to the catalytic oxidation cyclic voltammetric comparison diagram of methotrexate (MTX) in the phosphate buffer solution of pH=5.0
-1), can find out that by comparison diagram carbon nano tube modified electrode has fabulous catalytic oxidation effect to ascorbic acid.
Fig. 2 is for adopting cyclic voltammetry; Use naked glass-carbon electrode and prepared carbon nano tube modified electrode as working electrode respectively; Ag/AgCl (saturated KCl solution) is a contrast electrode; Platinum electrode is to electrode, and (wherein folic acid concentration is 10 mgL to the catalytic oxidation cyclic voltammetric comparison diagram of folic acid in the phosphate buffer solution of pH=5.0
-1), can find out that by comparison diagram carbon nano tube modified electrode has fabulous catalytic oxidation effect to folic acid, and under the same terms methotrexate (MTX) and folic acid oxidizing potential close.
Ion chromatograph Dionex ICS-1500 with U.S. Dai An company (Dionex); Ionpac AG11 (the guard column of 50mm * 4mm); Ionpac AS11 (the separating column of 50mm * 4mm); Adding 15% acetonitrile (v/v) with the pH=5.0 phosphate buffer solution is moving phase, and flow rate of mobile phase is 1.0 mL/min, and sample size is 25 μ L.ED40 electrochemical detector dc amps detects, and is working electrode with carbon nano tube modified electrode or naked glass-carbon electrode (contrast), and Ag/AgCl (saturated KCl solution) is a contrast electrode, and platinum electrode is to electrode, and detecting current potential is 0.9 V.Under this experiment condition, with chromatography of ions of the present invention-carbon nano tube modified electrode Electrochemical Detection analytic system, can be to folic acid, the quick separation detection of methotrexate (MTX).Fig. 3 for adopt this system respectively with naked glass-carbon electrode and carbon nano tube modified electrode as working electrode to methotrexate (MTX) and folic acid standard model (2 mgL
-1) the contrast colors spectrogram, Fig. 4 and Fig. 5 are respectively the mark-on sample chromatogram figure of blood and urine.The detectability of this method methotrexate (MTX) and folic acid is respectively 1.109 μ gL
-1, 2.805 μ gL
-1
Claims (2)
1. chromatography of ions-carbon nano tube modified electrode Electrochemical Detection analytic system is characterized in that, CNT is positively charged through covalent modification; Be adsorbed on naked glass-carbon electrode surface; Form novel carbon nano-tube film modified electrode, as working electrode, more be prone to methotrexate (MTX) and the folic acid that absorption is the negative ion attitude with this modified electrode; Naked relatively glass-carbon electrode greatly promotes the catalytic oxidation of methotrexate (MTX) and folic acid.
2. chromatography of ions according to claim 1-carbon nano tube modified electrode Electrochemical Detection analytic system; It is characterized in that this system may be used on can realizing separating fast of methotrexate (MTX) and folic acid with the chromatography of ions coupling in the electrochemical detector and detecting, detect when being fit in the complicated substrate biological species sample low concentration methotrexate (MTX) and folic acid.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103196983A (en) * | 2013-02-26 | 2013-07-10 | 浙江大学 | Method for simultaneous determination of methotrexate and calcium folinate |
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| US5403451A (en) * | 1993-03-05 | 1995-04-04 | Riviello; John M. | Method and apparatus for pulsed electrochemical detection using polymer electroactive electrodes |
| CN102288688A (en) * | 2010-12-02 | 2011-12-21 | 南京林业大学 | Method for determining xylooligosaccharide through high-efficiency liquid-phase ion exchange chromatography |
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| PANAGIOTIS KOUFOPANTELIS ET AL: "Direct injection liquid chromatography/positive ion electrospray ionization mass spectrometric quantification of methotrexate, folinic acid, folic acid and ondansetron in human serum", 《JOURNAL OF CHROMATOGRAPHY B》 * |
| 瞿万云 等: "甲氨呤在多壁碳纳米管膜修饰电极上的电化学行为及其测定", 《药物分析杂志》 * |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103196983A (en) * | 2013-02-26 | 2013-07-10 | 浙江大学 | Method for simultaneous determination of methotrexate and calcium folinate |
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Application publication date: 20121017 |