| Electrochemical sensor has been proved to be an attractive means due to its fast analysis speed,high sensitivity,simple preparation,low-cost apparatus and easy to integrate and miniaturize.As a novel detection method,it has been widely applied in various fields,such as clinical medicine monitoring,food safety,and environmental,etc.Porous metal materials due to their large specific surface area and interconnected structure play an important role in enhancing the sensitivity of the sensor.Molecularly imprinted polymers enable selective identification and quantitative detection of the target analytes in complex samples.As a modification material for sensing platform,it can improve the selective response,and the detection result is more accurate and reliable.In this paper,we developed two novel electrochemical sensor based on porous metal materials and molecularly imprinted polymer for the determination of histamine and resveratrol.The main content consists of the following two parts:?1?Bubble assisted deposition of a three-dimensional porous nickel film for the electrocatalytic oxidation of histamineThe author described an electrochemical sensor for ultrasensitive voltammetric of histamine?HA?by using a gold electrode?GE?that was modified with a film consisting of three-dimensional activated microporous nickel?3D-AMPNi/GE?.The porous nickel film was deposited on the electrode by bubble assisted electrodeposition.The sensor was characterized via scanning electron microscopy?SEM?,energy dispersive spectrometry?EDS?,X-ray photoelectron spectroscopy?XPS?and cyclic voltammetry?CV?in order to evaluate its morphology,composition and electrochemical properties.The pore size and wall thickness of the nickel skeleton were tailored by optimizing the concentration of the plating solution,operating temperature,and deposition time.Under the optimum conditions and in 0.1 M NaOH solution at a typical potential of 0.63 V?vs.Ag/AgCl?at a scan rate of 100 mV s-1,the sensor gave an analytical response over the 1.0×10-88 to 8.0×10-55 M HA concentration range,with a 4.2×10-99 M detection limit?S/N=3?and a 2.38?A?M-11 cm-22 sensitivity.The method is sensitive,repeatable,and the sensor is stable.It should be noted that one disadvantage of this method is the need for working in alkaline media,and further experiments are in progress to tackle this problem.?2?Molecularly imprinted polymers modified Au@Ag bimetallic hollow nanoshells for ultrasensitive determination of resveratrolIn this work,indium tin oxide electrodes?ITO?were used as the substrate of working electrode.First,Ag nanoparticles were deposited on ITO electrode surface by cyclic voltammetry?CV?.Next,Au@Ag bimetallic hollow nanoshells were prepared by a simple replacement reaction method between Ag nanoparticles and HAuCl4.A layer of molecularly imprinted polymer?MIP?was then fabricated in situ on the Au@Ag surface by electro-polymerization,with resveratrol?Res?acting as the template molecule and o-phenylenediamine as the functional monomer.Influencing factors during electro-polymerization process including pH value and molar ratio of template to monomer were optimized.Under the optimum conditions,the morphology of different modified electrodes was observed by scanning electron microscopy?SEM?.Energy dispersive spectrometry?EDS?was used to characterize the elemental composition of Ag/ITO and Au@Ag/ITO.Hexacyanoferrate was used as electrochemical probe,and electrochemical behavior of Res-MIP/Au@Ag/ITO was explored by CV and electrochemical impedance spectroscopy?EIS?.A linear range from 2×10-1111 to 8×10-99 M for measuring Res was obtained,with a low detection limit of 6.7×10-1212 M?S/N=3?.Besides,the developed sensor was successfully applied for monitoring Res in grape seed extract,and the results were in good accordance with those from HPLC in the same samples. |
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