| Morphine(MOP) is the main component in opium and at the same time it is also the common ftupetacient in clinical medicine.On the one hand it brings serious damages to social and drug addicts,on the other hand it relieves pain in surgical procedures.So it has very important realistic significance to detect the morphine contents in drug addicts and patients who was injected morphine.At present,there are many methods to detect it such as:chromatography,spectroscopy,immunoanalysis, electrochemistry sensors,in which the technology of electrochemistry sensors have a great development due to its simple,rapid and suitable for field analysis.Direct electrochemical oxidation of MOP on bare electrode required high overpotential,so it is reported reducing the oxidation potential through chemical modified electrode(CME) or the technology of molecule imprinting,while the method owned tedious procedure and unsatisfied stability and sensitivity.This paper's aim is to develop simple and fast new electrochemistry sensors to determination of MOP based on the gold nanoparticles(AuNPs).The major work consists of two parts:In the first part of this paper,The detection of Morphine used AuNPs/ITO electrode by direct electrodeposition.Firstly AuNPs were modified by directly electrochemistry deposition on the surface of ITO electrode,which owned controllable particle size.The obtained electrode was characterized by UV-vis,Scanning electron microscope(SEM), X-Ray diffraction(XRD),Electrochemistry Impedance Spectroscopy(EIS) technologies.The results showed the obtained AuNPs film presented symmetric distribution and the particles was about 25-30nm.Secondly,the AuNPs/ITO electrode could effectively reduce the oxidation overpotential of MOP and there was a obvious oxidation peak at 0.5v(vs SCE) by the cyclic voltammetry(CV) method.At optimal experimental condition:60 cycles for electrodeposition AuNPs on ITO surface,pH 7.0, 0.2 M phosphate buffer solution,the MOP oxidation current was response with its concentrations ranging from 8.0×10-7 to 1.0×10-4 mol/L,the detection limit was 2.6×10-7mol/L.This proposed method possessed a high accuracy,satisfied recovery from the results of detection of morphine in simulate sample,which was compared by HPLC.It is a convenient,sensitive and rapid method,which could be a hopeful tool for morphine detection.In the second part of this paper,a novel reagentless electrochemical immunosensor was obtained for determination of morphine based on AuNPs/PMB.The film of PMB was modified on bare glass carbon electrode(GCE) by electrochemical polymerization,which was used as electron mediators and electrostatic adherence gold nanoparticles(AuNPs) to attach anti-MOP.The anti-MOP/AuNPs/PMB/GCE reagentless electrochemical immunosensor was prepared which was charactered by the cyclic voltammograms(CVs),Electrochemical impedance spectroscopy(EIS) and Scanning electron microscope(SEM).The optimal conditions of PMB and the immunoreaetion were investigated.The results showed that AuNPs had two functions:on the one hand,it accelerated the conduct of electron;on the other hand,it enhanced the amount of Anti-MOP immobilized,under the optimal conditions:pH=8.0 PBS buffer solution,the incubation time was 25min,30℃was needed for incubation temperature,the CVs of the immmunosensor showed it had a lower detection limit(ng/mL) with its concentrations ranging from 20-160ng/mL.This modified electrode owned excellent selectivity,high stability and nicer rebirth capability, which also owned many virtue such as simple facture,cheap and high sensitivity.It also laid a good foundation for other drug's determination. |
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