Development of a chemiluminescence sensor based on molecular imprinting technology for the determination of trace monocrotophos in vegetables

2017 ◽  
Vol 37 (5) ◽  
pp. 1401-1409 ◽  
Author(s):  
Shoumin Wang ◽  
Peng Zhao ◽  
Ningyang Li ◽  
Xuguang Qiao ◽  
Zhixiang Xu
Luminescence ◽  
2011 ◽  
Vol 27 (4) ◽  
pp. 297-301 ◽  
Author(s):  
Zhenbo Liu ◽  
Fengyan Jia ◽  
Wenwen Wang ◽  
Cuixia Wang ◽  
Yongming Liu

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Navid Assi ◽  
Lukas Nejdl ◽  
Kristyna Zemankova ◽  
Kristyna Pavelicova ◽  
Jaroslava Bezdekova ◽  
...  

AbstractIn this work, we explored a new approach to a simple and sensitive fluorescence detection of thiols. The approach takes advantage of an in-situ formation of UV light-induced fluorescent nanoparticles (ZnCd/S quantum dots), while utilizing the thiol group of the analyte as a capping agent. The selectivity is ensured by the selective isolation of the thiol analyte by a polydopamine molecularly imprinted polymeric (MIP) layer. Based on this approach, a method for determination of thiols was designed. Key experimental parameters were optimized, including those of molecular imprinting and of effective model thiol molecule (l-cysteine) isolation. The relationship between the fluorescence intensity of ZnCd/S quantum dots and the concentration of l-cysteine in the range of 12–150 µg/mL was linear with a detection limit of 3.6 µg/mL. The molecularly imprinted polymer showed high absorption mass capacity (1.73 mg/g) and an excellent selectivity factor for l-cysteine compared to N-acetyl-l-cysteine and l-homocysteine of 63.56 and 87.48, respectively. The proposed method was applied for l-cysteine determination in human urine with satisfactory results. Due to a high variability of molecular imprinting technology and versatility of in-situ probe formation, methods based on this approach can be easily adopted for analysis of any thiol of interest.


2019 ◽  
Vol 15 (6) ◽  
pp. 628-634
Author(s):  
Rong Liu ◽  
Jie Li ◽  
Tongsheng Zhong ◽  
Liping Long

Background: The unnatural levels of dopamine (DA) result in serious neurological disorders such as Parkinson’s disease. Electrochemical methods which have the obvious advantages of simple operation and low-cost instrumentation were widely used for determination of DA. In order to improve the measurement performance of the electrochemical sensor, molecular imprinting technique and graphene have always been employed to increase the selectivity and sensitivity. Methods: An electrochemical sensor which has specific selectivity to (DA) was proposed based on the combination of a molecular imprinting polymer (MIP) with a graphene (GR) modified gold electrode. The performance and effect of MIP film were investigated by differential pulse voltammetry (DPV) and cyclic voltammetry (CV) in the solution of 5.0 ×10-3 mol/L K3[Fe(CN)6] and K4[Fe(CN)6] with 0.2 mol/L KCl at room temperature. Results: This fabricated sensor has well repeatability and stability, and was used to determine the dopamine of urine. Under the optimized experiment conditions, the current response of the imprinted sensor was linear to the concentration of dopamine in the range of 1.0×10-7 ~ 1.0×10-5 mol/L, the linear equation was I (µA) = 7.9824+2.7210lgc (mol/L) with the detection limit of 3.3×10-8 mol/L. Conclusion: In this work, a highly efficient sensor for determination of DA was prepared with good sensitivity by GR and great selectivity of high special recognization ability by molecular imprinting membrane. This proposed sensor was used to determine the dopamine in human urine successfully.


2014 ◽  
Vol 605 ◽  
pp. 67-70 ◽  
Author(s):  
Mohsen Rahiminezhad ◽  
Seyed Jamaleddin Shahtaheri ◽  
Mohammad Reza Ganjali ◽  
Abbas Rahimi Rahimi Forushani

Molecular imprinting technology has become an interesting research area to the preparation of specific sorbent material for environmental and occupational sample preparation techniques (1). In the molecular imprinting technology, specific binding sites have been formed in polymeric matrix, which often have an affinity and selectivity similar to antibody-antigen systems (2). In molecular imprinted technology, functional monomers are arranged in a complementary configuration around a template molecule, then, cross-linker and solvent are also added and the mixture is treated to give a porous material containing nono-sized binding sites. After extraction of the template molecule by washing, vacant imprinted sites will be left in polymer, which are available for rebinding of the template or its structural analogue (3). The stability, convention of preparation and low cost of these materials make them particularly attractive (4). These synthetic materials have been used for capillary electrochromatography (5), chromatography columns (6), sensors (7), and catalyze system (8). Depending on the molecular imprinting approach, different experimental variables such as the type and amounts of functional monomers, porogenic solvent, initiator, monomer to cross-linker ratio, temperature, and etc may alter the properties of the final polymeric materials. In this work, chemometric approach based on Central Composite Design (CCD) was used to design the experiments as well as to find the optimum conditions for preparing appropriate diazinon molecularly imprinted polymer.


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