| Molecular imprinting technique is to prepare to identify a target molecule specific recognition of the molecularly imprinted polymer (molecularly imprinted polymers, MIPs) technology. Since the molecularly imprinted polymer can adapt to the complex environment, the molecularly imprinted electrochemical sensor as identification of materials have increasingly attached considerable attention by the researchers.Meanwhile, MIPs has the characters such as predetermination, specific recognition and practicability, which has been widely applied in many fields such as the chemical, biological and medical. It has been reported that the MIPs film is almost small molecular to cause the MIPs film unevenness and also affected the stability of the electrochemical signal, poor regeneration and reversible, or poor adhesion to the electrode, which can limit the MIP application of the sensor. This paper using ethylene glycol maleic rosinate acrylate (EGMRA) as cross-linker, graphene doping metal nanoparticles materials signal amplification materials for preparation of the MIP sensor, we successfully fabricated the molecularly imprinted electrochemical sensor for carbamate pesticide residue detection of molecularly imprinted electrochemical sensor, applied for determination of carbamate pesticide residue in vegetable samples.The main contents are listed below:1. A new molecularly imprinted electrochemical sensor has been developed for detection of metolcarb (MTMC) by combination of graphene and gold nanoparticles. The molecularly imprinted polymer (MIP) was synthesized on graphene and gold nanoparticles modified glassy carbon electrode surface by using MTMC as template molecular, methyl acrylic acid as functional monomer, and ethylene glycol maleic rosinate acrylate (EGMRA) as cross-linker. The morphology of the MIP membrane was characterized by scanning electron microscope (SEM). The performance of the sensor was investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). A linear relationship between oxidation peak current and concentration of MTMC was obtained over a range from 1.0 ×10-7 to 1.0×10-4 mol/L(Linear regression coefficient= 0.9936) with a detection limit (S/N=3) of 2.9×10-8 mol/L. The imprinted sensor was successfully used to determine MTMC in vegetable samples with recovery ranging from 93.4% to 106.4% by using standard addition method.2. A novel molecularly imprinted electrochemical sensor was fabricated based on glassy carbon electrode decorated by reduced graphene oxide and gold nanoparticles (rGO@Au) for the detection of carbofuran (CBF).The molecularly imprinted polymers (MIPs) were prepared on the electrode surface with CBF as the template molecule, methyl acrylic acid as the functional monomer, and ethylene glycol maleic rosinate acrylate (EGMRA) as a cross-linker. The sensor was studied with respect to its response to hexacyanoferrate (Ⅲ) as a probe and characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under the optimum conditions, the peak current of the sensor and CBF concentration showed a good linear relationship over the range from 5.0×10-8 to 2.0×10-5 mol/L,with the detection limit 2.0×10-8 mol/L (S/N=3). The sensor exhibited high adsorption capacity and good selectivity for CBF and it was successfully applied to the detection of CBF in real vegetable samples with recoveries 97.7%～110.6%.3. A novel molecularly imprinted electrochemical sensor has been developed for detection of 3,5-Xylyl methylcarbamate (XMC) by combination of graphene and gold nanoparticles. The molecularly imprinted polymers (MIP) was synthesized on grapheme and gold nanoparticles modified glassy carbon electrode surface by using XMC as template molecular, methyl acrylic acid as functional monomer, and ethylene glycol maleic rosinate acrylate (EGMRA) as cross-linker. The morphology of the sensing membrane was characterized by scanning electron microscope (SEM). The performance of the sensor was investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). A linear relationship between oxidation peak current and concentration of XMC was obtained over a range from 1.O×10-7 to 2.0×10-5 mol·L-1 (Linear regression coefficient= 0.9979) with a detection limit(S/N=3) of 1.5×10-8mol·L-1. From the selectivity experiments, the imprinting factor β of XMC imprinted film was 2.94 and the selectivity factors a of XMC compared to interference were all larger than 1. Although a minor interference was generated by XMC for its structure similar to Metolcarb, the selectivity factor also reached 2.39. The results indicated that the imprinted polymer films exhibited excellent selectivity for XMC. The kinetics of recognition suggested that a process of the imprinted polymer films adsorbing XMC is langmuir model and its kinetic rate constant is 73.05 s. The imprinted sensor was successfully used to determine XMC in vegetable samples with recovery ranging from 95.4% to 108.0% by using standard addition method.4. A sensitive electrochemical sensor for carbaryl (CBR) was prepared based on molecular imprinting strategy by thermal polymerization. The molecularly imprinted polymers (MIP) was synthesized on graphene and gold nanoparticles modified glassy carbon electrode surface by using CBR as template molecular, methyl acrylic acid as functional monomer, and ethylene glycol maleic rosinate acrylate (EGMRA) as cross-linker. The morphology of the sensing membrane was characterized by scanning electron microscope (SEM). The sensor was studied with respect to its response to hexacyanoferrate (III) as a probe and by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). The linear response range to CBR is from 1.O×10-8 to 1.0×10-6 mol·L-1(Linear regression coefficient= 0.9956) with a detection limit (S/N=3) of 2.5×10-9 mol·L-1. The sensor exhibited high adsorption capacity and good selectivity for CBR and it was successfully applied to the detection of CBR in real vegetable samples. |
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