Construction Of Molecularly Imprinted Electrochemiluminescence Sensor And Detection Of Small Organic Molecules

The Electroluminescence（ECL）method has many advantages because of its low background interference,free of extra light source,high sensitivity,so as to have promising application potential in the chemical detection field.Nevertheless,the ECL is susceptible to same kinds of substances and with a poor selectivity.The introduction of Molecular imprinted polymer（MIP）,which can recognize the target molecules accurately,will improve the selectivity of ECL method.Furthermore,a stable material with strong luminescence signal is required.Among various kinds of ECL luminescent materials,graphite-like carbon nitride nanosheets（g-C₃N₄NSs）has the advantages of straightforward synthesis,strong luminescent activity,convenient functionalization so that has been widely adopted by scientists and researchers.In this paper,a ECL-MIP sensor was developed for the purpose of detecting organophosphorus pesticide chlorpyrifos,Phenolic hydroxyl drug molecules folic acid and salicylic acid.The g-C₃N₄NSs synthesized by our lab were utilized as luminescent materials.The paper is arranged as follows:1.The establishment and application of MIP-ECL sensor detecting Chlorpyrifos.g-C₃N₄NSs was fixed to the surface of electrode as g-C₃N₄NSs/GCE.MIP was introduced to g-C₃N₄NSs/GCE by radical thermal polymerization,obtaining MIP/g-C₃N₄NSs/GCE.After the CPF was eluted,a MIP-ECL sensor for specific and sensitive CPF detection was developed,with linear response range 1.0×10^-8～1.0×10^-4mol·L^-1and the limit of detection（LOD）5 n mol·L^-1.2.Au doping g-C₃N₄NSs system detecting folic acidThe ECL intensity of g-C₃N₄NSs increase with potential.However,the intensity becomes instable when the potential is larger then-1.0V.The introduction of Au NPs would alleviate this problem.Its excellent electron reception capability can help to transfer extra high energy electron produced at high potential,which avoids passivation of electrode and improvements the stability.In the study of this paper,we have introduced Au NPs in g-C₃N₄NSs as Au-g-C₃N₄NSs complex.The synthesized Au-g-C₃N₄NSs complex was fixed on GCE obtaining Au-g-C₃N₄NSs/GCE.Then the MIP was introduced on Au-g-C₃N₄NSs/GCE using electropolymerization with template FA,monomer acrylamide.A sensitive detection of FA was achieved by the double quenching effect on the sensor.The sensor has showed a linear response in range of 1.0×10^-10～1.0×10^-3mol·L^-1,with LOD 0.07 nmol·L^-1.3.Au-g-C₃N₄NSs/N-CDs anode system detecting salicylic acid（SA）Quite a lot of researches have been done based on cathode Au-g-C₃N₄ECL.While less attention was paid to anode luminescence.The g-C₃N₄anodic coreactant is usually triethanolamine which is toxic,corrosive and volatile.For the purpose of high sensitivity detection,a high concentration(100 mmmol·L^-1)of triethanolamine is requred.The eco-friendly and low toxic N-CDs was synthesized in the work,adopted as anodic coreactant of Au-g-C₃N₄NSs.The effect of N-CDs was studied that the existence of N-CDs would strengthen the ECL signal of anode.A sensitive detection of SA was accomplished by the quenching effect of SA on ECL signal of Au-g-C₃N₄NSs anode.