The aim of this study was the preparation of polypyrrole (PPy) fibers for solid phase microextraction (SPME). PPy coatings were obtained during the electrochemical polymerization process. The utility of various metal wires (Fe, Cu, Ag, Cu/Ag, kanthal and medical stainless steel) as a support for polymers was compared. Various experimental conditions of the synthesis process such as scan rate, voltage limits and number of scans and deposition time were applied. The average polymer thickness was in the range of 7-125 microm and its weight was in the scope of 0.65-5.6 mg. Different techniques, mainly elemental analysis, Fourier transform infrared spectroscopy, microscopy, and chromatography were performed for the characterization of obtained fibers with microporous structure. The extraction efficiency of cardiovascular drugs (metoprolol, propranolol, oxprenolol, propafenone and mexiletine) by means of fibers was tested. The concentration of mentioned compounds in standard solution was in the span of 10-150 ng/mL. LC-MS was employed for determination of drugs in desorption solution. LODs varied from 0.013 to 1.51 ng/mL for metoprolol and mexiletine respectively. The repeatability of extraction was obtained with the RSD values lower than 10%.
Background:
Molecularly imprinted polymers (MIPs) are utilized in the separation of a
pure compound from complex matrices. A stable template-monomer complex generates MIPs with
the highest affinity and selectivity for the template. In this investigation, degradation of
Poly(ethylene terephthalate) PET afforded the (E)-4-(2-cyano-3-(dimethylamino) acryloyl) benzoic
acid (4) (TAM) which used TAM as template which interacts with Methacrylic Acid (MAA)
monomer, in the presence of CH3CN as progen. The TAM-MMA complex interactions are dependent
on stable hydrogen bonding interaction between the carboxylic acid group of TAM and the
hydroxyl group of MMA with minimal interference of porogen CH3CN. The DFT/B3LYP/6-31+G
model chemistry was used to optimize their structures and frequency calculations. The binding energies
between TAM with different monomers showed the most stable molar ratio of 1:4 which was
confirmed through experimental analysis.
Methods:
The present work describes the synthesis of (E)-4-(2-cyano-3-(dimethylamino) acryloyl)
benzoic acid (4) (TAM) from PET waste and formation of molecularly imprinted polymer from
TAM with the methacrylic acid monomer. The optimization of molecular imprinted was stimulated
via DFT/B3LYP/6-31G (d). The imprinted polymer film was characterized via thermal analysis, pore
size, FT-IR and scanning electron microscopy.
Results:
The most stable molecularly imprinted polymers (MIPs) showed binding energy of
TAM(MMA4)=-2063.456 KJ/mol with a small value of mesopores (10-100 Å). Also, the sorption
capability of TAM-MIPs showed 6.57 mg/g using STP-MIP-9VC. Moreover, the average pore size
ranged between 0.2-1 nm with the BET surface about 300 m2/g.
Conclusion:
The proposed TAM exhibited a high degree of selectivity for MMA in comparison with
other different monomers through hydrogen bond interaction, which was thermally stable, good reproducibility
and excellent regeneration capacity and elucidated in the computational study and analytical
analysis.
The paper reviews several methods for the preparation of chitosan-originated nitrogenrich activated carbons N_AC. The review considers the historical aspect of the synthesis development including the first scientific paper and patent application in this field. The relationship between the method for N_AC manufacturing from chitosan and their textural properties as surface area, total pore volume, and the nature of the porosity is presented. The influence of the N_AC obtaining method on the nitrogen content in the carbons is discussed, too. Identified potential applications of chitosan-originated N_ACs are described in relation to their basic physical and chemical properties.
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