A melamine piezomicrogravimetric (acoustic) chemosensor using a molecularly imprinted polymer (MIP) film has been devised and tested. The MIP films were prepared by electropolymerization of the melamine complexed by the functional monomer of the bis(bithiophene) derivative bearing an 18-crown-6 substituent 4. The structure of the MIP-melamine complex was visualized by the DFT B3LYP/3-21G(*) energy optimization calculations. The sensitivity and selectivity of the MIP film was improved by cross-linking the polymer with the bithianaphthene monomer 5 and the presence of the porogenic ionic liquid in the prepolymerization solution. After electropolymerization, the melamine template was extracted from the MIP film with an aqueous strong base solution. The measurements of UV-vis spectroscopy, X-ray photoelectron spectroscopy (XPS), DPV, and EIS as well as scanning electrochemical microscopy (SECM) imaging confirmed extraction of the melamine template from the MIP film and then rebinding of the melamine analyte while the film relative roughness and porosity was determined by atomic force microscopy (AFM) and scanning electron microscopy (SEM) imaging, respectively. The analytical as well as kinetic and thermodynamic parameters of the chemosensing were assessed under flow-injection analysis (FIA) conditions with piezoelectric microgravimetry (PM) detection. The linear concentration range for melamine detection was 5 nM to at least 1 mM with a limit of detection of approximately 5 nM. The chemosensor successfully discriminated the cyanuric acid, cyromazine, and ammeline interfering agents.
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http://dx.doi.org/10.1021/ac9020352 | DOI Listing |
Carbohydr Polym
March 2025
Bioresource Processing Research Institute of Australia, Department of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, Australia. Electronic address:
Structural analysis of cellulose nanofibril (CNF) films remains challenging due to the stochastic assembly of fibres and presence of nanopores. This limits our ability to link the film structures to their properties, restricting their commercial use. While X-ray micro-computed tomography (μCT) is a powerful technique to map the structure of traditional and commercial paper, there has been limited success in its application for CNF films due to the poor contrast between pores and material, making the reconstructed images difficult to segment and analyse.
View Article and Find Full Text PDFJ Thorac Dis
December 2024
Department of Diagnostic Radiology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Chest computed tomography (CT) is the most frequently performed imaging examination worldwide. Compared with chest radiography, chest CT greatly improves the detection rate and diagnostic accuracy of chest lesions because of the absence of overlapping structures and is the best imaging technique for the observation of chest lesions. However, there are still frequently missed diagnoses during the interpretation process, especially in certain areas or "blind spots", which may possibly be overlooked by radiologists.
View Article and Find Full Text PDFMolecules
December 2024
Institute of Materials Science, Kaunas University of Technology, K. Baršausko 59, LT-51423 Kaunas, Lithuania.
This study explores the low-temperature synthesis of graphene using plasma-enhanced chemical vapor deposition (PECVD), emphasizing the optimization of process parameters to achieve controlled growth of pristine and hydrogenated graphene. Graphene films were synthesized at temperatures ranging from 700 °C to as low as 400 °C by varying methane (25-100 sccm) and hydrogen (25-100 sccm) gas flow rates under 10-20 mBar pressures. Raman spectroscopy revealed structural transitions: pristine graphene grown at 700 °C exhibited strong 2D peaks with an I(2D)/I(G) ratio > 2, while hydrogenated graphene synthesized at 500 °C showed increased defect density with an I(D)/I(G) ratio of ~1.
View Article and Find Full Text PDFAnal Methods
January 2025
School of Public Health, Hebei Medical University, Shijiazhuang, 050017, P.R. China.
In this study, a molecularly imprinted electrochemical sensor (MIECS) was constructed based on the combination of graphene quantum dots-gold nanoparticles (GQDs-AuNPs), molecular imprinting polymer (MIP), and electrochemical technology for the ultra-sensitive detection of 17β-estradiol (E). GQDs-AuNPs were synthesized and modified on the surface of glassy carbon electrodes (GCE). Safranine T was used as the functional monomer and E was the template molecule for self-assembly and electropolymerization, thus generating an MIP film on the electrode surface.
View Article and Find Full Text PDFJ Hazard Mater
December 2024
State Key Laboratory of Pollution Control and Resources Reuse (Tongji University), College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China. Electronic address:
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