Application Of Electrochemical Sensor Based On Carbon Material In The Detection Of Drug And Disease Marker

Electrochemical sensors are the combination of electrochemical analysis and sensor technology,which have wide application prospects.The advantages of electrochemical sensors are simple operation,fast analysis,low cost,good stability,good selectivity,high accuracy and high sensitivity.Researchers have paid more attention to electrochemical sensors,owing to these advantages of electrochemical sensors.Electrochemical sensors have been applied in many research fields such as pharmaceutical analysis,environmental monitoring,clinical monitoring and other research fields.With the efforts of many researchers,some excellent nanomaterials have been successfully applied to electrochemical sensor,such as graphene,carbon nanotubes,metallic nanomaterials and other nanomaterials.These excellent nanocomposites are modified to the surface of electrode,which can accelerate the electron transfer,enhance the electrocatalytic effect,improve the stability and selectivity of the sensor,and can be used in the detection of practical samples.In this study,several electrochemical sensors modified with different nanomaterials were prepared and applied to the detection of drugs and disease markers.The main contents of this paper can be summarized into the following four aspects:（1）Electrochemical sensor modified by CoPP-MnO₂-CB for simultaneous determination of enalapril maleate and hydrochlorothiazideGreen soluble starch as reducing agent,cyclodextrin as surfactant,MnO₂ was prepared by a simple water bath method.Based on the MnO₂,composite of Meso-tetraphenylporphyrin cobalt（Copp）and carbon black（CB）,CoPP-MnO₂-CB nanomaterials were prepared.A novel CoPP-MnO₂-CB/GCE electrochemical sensor was prepared on a glassy carbon electrode（GCE）modified with a new composite nanomaterial for simultaneous detection of two antihypertensive drugs,enalapril maleate（EM）and hydrochlorothiazide（HCT）.Under the optimal detection conditions,the linear ranges of EM and HCT are 0.50¹0.00μM and0.08⁴.00μM,respectively,the detection limits are 185.0 nM and 26.0nM,respectively.An electrochemical sensor for simultaneous determination of enalapril maleate and hydrochlorothiazide was established for the first time.（2）A non-enzymatic electrochemical sensor for detection of sialic acid based on indicator displacement assayBased on the indicator displacement assay（IDA）of dopamine,a non-enzymatic electrochemical sensor was developed for the detection of sialic acid（SA）.The electrode was fabricated by composite modification of Tetra（4-carboxyphenyl）porphine-graphene oxide,dopamine and2-fluorophenyl-boronic acid on glassy carbon electrode,respectively.The UV-vis absorption spectra of FPBA-DA/TCPP-GO/GCE and the electrochemical behavior of FPBA-DA/TCPP-GO/GCE were investigated.The reaction time of FPBA and DA/TCPP-GO/GCE,the pH of phosphate buffer solution and the proportion of TCPP and GO in the experiment were investigated.The influence of common interferences on the determination of SA were studied.Dopamine peak current response was linear with the SA concentration in the range of 0.1⁷.5 mM with a detection limit of 28.5μM.The recoveries of the experiment were98.0%¹04.0%.The new composite TCPP-GO significantly improved the sensitivity of electrochemical sensors.The non-enzymatic method was firstly used to analyze the content of sialic acid in biological samples.The advantages of this method are simple operation,good selectivity,low reagent toxicity and low-cost.（3）A sarcosine electrochemical sensor based on biomimetic recognitionA nonenzymatic electrochemical sensor is described for the detection of prostate cancer biomarker sarcosine（Sar）.Riboflavin was employed to mimic the active center of the enzyme sarcosine oxidase for constructing the biomimetic sensor.The use of riboflavon（Rf）avoids the disadvantages of an enzymatic sensor,such as high cost and poor stability.A glassy carbon electrode（GCE）was modified with a graphene-chitosan（GR）composite and further modified with gold-platinum bimetallic nanoparticles in a polypyrrole（PPy）matrix in order to enhance the catalytic activity of the enzyme mimic.Finally,Rf was electrodeposited on the surface of the AuPt-PPy/GR-modified GCE.Under optimized conditions,the GCE provided high sensitivity and selectivity for Sar at around 0.61 V.Response covers the 2.50⁶00.00μM concentration range,and the detection limit is 0.68μM.The method was successfully applied to the determination of Sar in spiked urine with 98.0%¹03.2%recoveries.（4）Preparation and application of enzyme-free electrochemical sensor modified by FeS₂-CNT-APBA for sialic acid dectectionBased on the principle of boric acid-based specific recognition of sialic acid,an enzyme-free electrochemical sensor for detection of sialic acid（SA）was prepared.Ferrous disulfide-carbon nanotubes-aminophenylboric acid nanomaterial（FeS₂-CNT-APBA）was synthesized by the combination of carboxylated carbon nanotubes and amino groups of 3-aminophenylboronic acid（APBA）,and the FeS₂-CNT-APBA/GCE was prepared successfully.FeS₂ and carbon nanotubes can enhance the conductivity of the electrode.Sialic acid can be quantitatively detected by the change of peak current after recognition between aminophenylboric acid and sialic acid.Under the optimal conditions,the linear range is 0.1¹.0 mM and the detection limit is 38.0μM.The sensor has good repeatability and stability and had been successfully applied to the detection of practical samples.