scholarly journals A Comparison of EIS and QCM NanoMIP-Based Sensors for Morphine

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3360
Author(s):  
Roberta D’Aurelio ◽  
Ibtisam E. Tothill ◽  
Maria Salbini ◽  
Francesca Calò ◽  
Elisabetta Mazzotta ◽  
...  
Keyword(s):  
Quartz Crystal ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Polymer Nanoparticles ◽  
Low Molecular Weight ◽  
Data Handling ◽  
Imprinted Polymer ◽  
Molecularly Imprinted ◽  
Sensing Platforms ◽  
Assay Design

In this work we have compared two different sensing platforms for the detection of morphine as an example of a low molecular weight target analyte. For this, molecularly imprinted polymer nanoparticles (NanoMIP), synthesized with an affinity towards morphine, were attached to an electrochemical impedance spectroscopy (EIS) and a quartz crystal microbalance (QCM) sensor. Assay design, sensors fabrication, analyte sensitivity and specificity were performed using similar methods. The results showed that the EIS sensor achieved a limit of detection (LOD) of 0.11 ng·mL−1, which is three orders of magnitude lower than the 0.19 µg·mL−1 achieved using the QCM sensor. Both the EIS and the QCM sensors were found to be able to specifically detect morphine in a direct assay format. However, the QCM method required conjugation of gold nanoparticles (AuNPs) to the small analyte (morphine) to amplify the signal and achieve a LOD in the µg·mL−1 range. Conversely, the EIS sensor method was labor-intensive and required extensive data handling and processing, resulting in longer analysis times (~30–40 min). In addition, whereas the QCM enables visualization of the binding events between the target molecule and the sensor in real-time, the EIS method does not allow such a feature and measurements are taken post-binding. The work also highlighted the advantages of using QCM as an automated, rapid and multiplex sensor compared to the much simpler EIS platform used in this work, though, the QCM method will require sample preparation, especially when a sensitive (ng·mL−1) detection of a small analyte is needed.

scholarly journals Electrochemical Sensor Based on Molecularly Imprinted Polymer for the Detection of Cefalexin

Biosensors ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 31 ◽  
Author(s):  
Bogdan Feier ◽  
Adrian Blidar ◽  
Alexandra Pusta ◽  
Paula Carciuc ◽  
Cecilia Cristea
Keyword(s):  
Electrochemical Sensor ◽  
Molecularly Imprinted Polymer ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Imprinted Polymer ◽  
Boron Doped Diamond ◽  
Molecularly Imprinted ◽  
Diamond Electrode ◽  
The Difference ◽  
Mip Sensor

In this study, a new electrochemical sensor was developed for the detection of cefalexin (CFX), based on the use of a molecularly imprinted polymer (MIP) obtained by electro‒polymerization in an aqueous medium of indole-3-acetic acid (I3AA) on a glassy carbon electrode (GCE) and on boron-doped diamond electrode (BDDE). The two different electrodes were used in order to assess how their structural differences and the difference in the potential applied during electrogeneration of the MIP translate to the performances of the MIP sensor. The quantification of CFX was performed by using the electrochemical signal of a redox probe before and after the rebinding of the template. The modified electrode was characterized using atomic force microscopy (AFM), scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The influence of different parameters on the fabrication of the sensor was tested, and the optimized method presented high selectivity and sensitivity. The MIP-based electrode presented a linear response for CFX concentration range of 10 to 1000 nM, and a limit of detection of 3.2 nM and 4.9 nM was obtained for the BDDE and the GCE, respectively. The activity of the sensor was successfully tested in the presence of some other cephalosporins and of other pharmaceutical compounds. The developed method was successfully applied to the detection of cefalexin from real environmental and pharmaceutical samples.

scholarly journals 3,4-Methylenedioxypyrovalerone (MDPV) Sensing Based on Electropolymerized Molecularly Imprinted Polymers on Silver Nanoparticles and Carboxylated Multi-Walled Carbon Nanotubes

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 353
Author(s):  
Rosa A. S. Couto ◽  
Constantino Coelho ◽  
Bassim Mounssef ◽  
Sara F. de A. Morais ◽  
Camila D. Lima ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Silver Nanoparticles ◽  
Density Functional ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Imprinted Polymer ◽  
Dft Methods ◽  
Molecularly Imprinted ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

3,4-methylenedioxypyrovalerone (MDPV) is a harmful and controlled synthetic cathinone used as a psychostimulant drug and as sport-enhancing substance. A sensor was developed for the direct analysis of MDPV by transducing its oxidation signal by means of an electropolymerized molecularly imprinted polymer (e-MIP) built in-situ on the screen-printed carbon electrode’s (SPCE) surface previously covered with multi-walled carbon nanotubes (MWCNTs) and silver nanoparticles (AgNPs). Benzene-1,2-diamine was used as the functional monomer while the analyte was used as the template monomer. Each step of the sensor’s development was studied by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in a solution containing ferricyanide, however no redox probe was required for the actual MDPV measurements. The interaction between the poly(o-phenylenediamine) imprinted polymer and MDPV was studied by density-functional theory (DFT) methods. The SPCE-MWCNT-AgNP-MIP sensor responded adequately to the variation of MDPV concentration. It was shown that AgNPs enhanced the electrochemical signal by around a 3-fold factor. Making use of square-wave voltammetry (SWV) the developed sensor provided a limit of detection (LOD) of 1.8 μmol L–1. The analytical performance of the proposed sensor paves the way to the development of a portable device for MDPV on-site sensing to be applied in forensic and doping analysis.

Liquid Chromatography Analysis of Clozapine in Rat Brain Tissue, Using its Molecularly Imprinted Polymer after Administration of Toxic Dose of Drug and Lipid Emulsion Therapy

2019 ◽  
Vol 15 (3) ◽  
pp. 251-257
Author(s):  
Bahareh Sadat Yousefsani ◽  
Seyed Ahmad Mohajeri ◽  
Mohammad Moshiri ◽  
Hossein Hosseinzadeh
Keyword(s):  
Rat Brain ◽  
Brain Tissue ◽  
Molecularly Imprinted Polymer ◽  
Lipid Emulsion ◽  
Limit Of Detection ◽  
Imprinted Polymer ◽  
Toxic Dose ◽  
Molecularly Imprinted ◽  
The Brain ◽  
Rat Brain Tissue

Background:Molecularly imprinted polymers (MIPs) are synthetic polymers that have a selective site for a given analyte, or a group of structurally related compounds, that make them ideal polymers to be used in separation processes.Objective:An optimized molecularly imprinted polymer was selected and applied for selective extraction and analysis of clozapine in rat brain tissue.Methods:A molecularly imprinted solid-phase extraction (MISPE) method was developed for preconcentration and cleanup of clozapine in rat brain samples before HPLC-UV analysis. The extraction and analytical process was calibrated in the range of 0.025-100 ppm. Clozapine recovery in this MISPE process was calculated between 99.40 and 102.96%. The limit of detection (LOD) and the limit of quantification (LOQ) of the assay were 0.003 and 0.025 ppm, respectively. Intra-day precision values for clozapine concentrations of 0.125 and 0.025 ppm were 5.30 and 3.55%, whereas inter-day precision values of these concentrations were 9.23 and 6.15%, respectively. In this study, the effect of lipid emulsion infusion in reducing the brain concentration of drug was also evaluated.Results:The data indicated that calibrated method was successfully applied for the analysis of clozapine in the real rat brain samples after administration of a toxic dose to animal. Finally, the efficacy of lipid emulsion therapy in reducing the brain tissue concentration of clozapine after toxic administration of drug was determined.Conclusion:The proposed MISPE method could be applied in the extraction and preconcentration before HPLC-UV analysis of clozapine in rat brain tissue.

scholarly journals A Molecularly Imprinted Polymer for Selective Extraction of Phenolic Acids from Human Urine

2021 ◽  
Vol 11 (4) ◽  
pp. 1577
Author(s):  
Marco Mora-Granados ◽  
David González-Gómez ◽  
Jin Su Jeong ◽  
Alejandrina Gallego-Picó
Keyword(s):  
Phenolic Acids ◽  
Molecularly Imprinted Polymer ◽  
Human Urine ◽  
Limit Of Detection ◽  
Ph Dependence ◽  
Selective Extraction ◽  
Screening Methods ◽  
Specific Method ◽  
Imprinted Polymer ◽  
Molecularly Imprinted

Studies for monitoring the bioavailability of dietary flavonoid compounds generate great interest. Among them, low-molecular-weight phenolic acids, secondary metabolites present in colonic catabolism and urinary excretion, have been proposed as biomarkers of polyphenol intake. Using 4-hydroxyphenylacetic acid as a template, a molecularly imprinted polymer (MIP) was synthesized for selective extraction of these hydroxylated metabolites from human urine samples and posterior analysis in an HPLC-DAD-MS system. Polymers were characterized by Scanning electron microscopy (SEM), Attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), Brunauer-Emmett-Teller (BET) method, and binding experiments. MIP presents specific recognition ability for template and analogues molecules. This capacity of recognition and the pH dependence of the binding strength was also studied. The method was validated over a concentration range of 0.25–40 mg/L, r2 > 0.995. In the optimized conditions, the recovery value was 94% with RSD 1.2%. The Limit of Detection (LOD) and Limit of Quantification (LOQ) were 1.22 and 3.69 mg/L, respectively. In our knowledge, it is the first time that this methodology is applied to analyze urinary catabolites of the polyphenol compound and to provide a specific method and simple analysis alternative. The selective extraction of these metabolites improves the application and results obtained by other less sensitive analysis methods than the validation method. It also facilitates the development of new screening methods.

Identification and detection of bioactive compounds in turmeric (Curcuma longa L.) using gas sensor array based on molecularly imprinted polymer quartz crystal microbalance

2021 ◽  
Author(s):  
Fajar IAIN Hardoyono ◽  
Kikin Windhani
Keyword(s):  
Gas Sensor ◽  
Bioactive Compounds ◽  
Quartz Crystal Microbalance ◽  
Molecularly Imprinted Polymer ◽  
Quartz Crystal ◽  
Sensor Array ◽  
Curcuma Longa ◽  
Imprinted Polymer ◽  
Molecularly Imprinted ◽  
Gas Sensor Array

This study aimed to identify four bioactive compounds in turmeric (Curcuma longa L.) using gas sensor array based on molecularly imprinted polymer-quartz crystal microbalance (MIP-QCM). Four QCM sensors coated with...

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