The Construction Of Electrochemical Sensor Modified With Carbon Nanomaterials And Its Application In Methotrexate Detection

Objective:The electrochemical sensor based on carbon nanomaterials is constructed for the detection of drug concentration of methotrexate(MTX),and the composite modification of other carbon materials and surfactants is added on the basis of a single carbon material to further improve the sensitivity of the electrochemical sensor to MTX detection.A new method for rapid,sensitive and accurate detection of MTX in plasma based on electrochemical sensor is established to provide new technical support for the detection of MTX drug concentration.Methods:1.The homogeneous water suspension of various carbon nanomaterials was prepared by ultrasonic dispersion and the suspension was dropped to the surface of glassy carbon electrode(GCE)to prepare the working electrode.Cyclic voltammetry(CV)was selected as the experimental method of electrochemistry,with the electrochemical oxidation peak current value of MTX as the standard,and the carbon nanomaterial with the optimal catalytic effect on MTX was selected to build a novel electrochemical sensor of MTX with AB/GCE as the working electrode.After optimizing and selecting the influencing factors or parameters such as AB suspension on the electrode surface,MTX enrichment time,buffer p H and CV scanning rate,verifying the linear and detection limit test,precision test,interference test and recovery test,finally the prepared sensor was used for the detection of actual samples.2.In order to further improve the detection performance of the above prepared electrochemical sensors for MTX,on the basis of AB/GCE,high-end conductive nanomaterials-multi-walled carbon nanotube(MWCNT)and surfactant were introduced to compound and modify the electrode.CV was selected as the electrochemical detection method,using the electrochemical oxidation peak current values of MTX as the standard,to select the best carbon nanomaterials combination AB/MWCNT and the best cationic surfactant-stearyl trimethyl ammoium chloride(STAC),and the three materials were combined to prepare AB/MWCNT/STAC-PE for novel electrochemical sensor.AB/MWCNT/STAC-PE electrode was characterized by electrochemical impedance spectra(EIS)The influencing factors or parameters such as quality ratio of carbon nanomaterials affecting sensor performance,amount of carbon paste adhesive,surfactant modification,MTX enrichment time and stirring rate,and buffer p H and CV scanning rate were optimized.Finally,the linearity and detection limit,precision,accuracy and accuracy,interference test and recovery test were verified under the optimal conditions.Results:1.The novel MTX electrochemical sensor with AB/GCE as the working electrode was prepared.The electrochemical behavior of MTX on AB/GCE electrode was studied by CV,which showed that the MTX electrochemical reaction was a surface-controlled and irreversible oxidation process of transferred two electrons with single proton,and the oxidation peak current values were proportional to the MTX concentrations.The sensitive determination of MTX was completed under optimal conditions.The prepared sensor performed excellent linearly within the allowable error range and possessed two linear ranges,0.005 μM～0.2 μM and 0.2 μM～3 μM,with linear correlation coefficient of 0.9916 and 0.9970 respectively;the limit of detection(LOD)was 3.81 n M,which showed high analytical sensitivity.In addition,the sensor conducted good stability,reproducibility,anti-interference,and accuracy,which would provide a new method for the detection of MTX drug concentration in clinical samples.2.A novel MTX electrochemical sensor with AB/MWCNT/STAC-PE as the working electrode was prepared.The electrochemical behavior of MTX on the AB/MWCNT/STAC-PE electrodes was studied by CV,which showed the MTX electrochemical reaction was a surface-controlled and completely irreversible oxidation process of transferred two electrons and two protons.Under the optimal conditions,the sensor was well linearly within the allowable error range,with linear range of 0.02 μM～8μM and linear correlation coefficient of 0.99653;and possessed a lower LOD of 1.85 n M,further improving the analysis sensitivity.Method verification showed that the method had good precision and accuracy.Finally,MTX was detected in the clinical samples with the prepared sensor and the results were statistically compared with the results obtained from conventional methods,which showed good agreement.Conclusions:The study constructed two novel electrochemical sensors for MTX drug concentration detection.Compared with the existing MTX electrochemical sensors,the novel MTX electrochemical sensors prepared in this study have high sensitivity and the advantages of equipment miniaturization,quick operation and low cost.Compared with the results of the conventional MTX detection methods,the two have a good consistency,which can be complementary with the conventional detection methods.The construction of these two new electrochemical sensors provides new technical support for the detection of MTX drug concentration,and promotes the application of electrochemical detection method in the field of anti-tumor drug concentration detection,which has important clinical significance and broad application prospect.