Microextraction by packed molecularly imprinted polymer followed by ultra-high performance liquid chromatography for determination of fipronil and fluazuron residues in drinking water and veterinary clinic wastewater

Magnetic solid-phase extraction based on restricted-access molecularly imprinted polymers for ultrarapid determination of ractopamine residues from food samples by capillary electrophoresis

An ultrafast, efficient, and eco-friendly method combining magnetic solid phase extraction and capillary electrophoresis with diode array detection have been developed to determine ractopamine residues in food samples. A restricted access material based on magnetic and mesoporous molecularly imprinted polymer has been properly synthesized and characterized, demonstrating excellent selectivity and high adsorbent capacity. Short-end injection capillary electrophoresis method was optimized: 75 mM triethylamine pH 7 as BGE, -20 kV, 50 mbar by hydrodynamic injection during 8 s, and capillary temperature at 25 °C; reaching ultrafast ractopamine analysis (∼0.6 min) with good peak asymmetry, and free from interfering and/or baseline noise. After sample preparation optimization, the conditions were: 1000 µL of sample at pH 6, 20 mg of adsorbent, stirring time of 120 s, 250 µL of ultrapure water as washing solvent, 1000 µL of methanol: acetic acid (7: 3, v/v) as eluent, and the adsorbent can be reused four times. In these conditions, the analytical method showed recoveries around to 100 %, linearity ranged from 9.74 to 974.0 µg kg-1, correlation coefficient (r) ≥ 0,99 in addition to adequate precision, accuracy, and robustness. After proper validation, the method was successfully applied in the analysis ractopamine residues in bovine milk and bovine and porcine muscle.

Levobunolol-imprinted polymer: a theoretical study

CONTEXT

Levobunolol is a β-blocker drug prescribed for the control and prevention of cardiovascular events, such as individuals with cardiac arrhythmia or a history of myocardial infarction. Creating a levobunolol-specific molecularly imprinted polymer (MIP) allows for enhanced selectivity, efficient sample preparation, controlled drug delivery, and improved sensing and detection capabilities. In this sense, the aim of this study was to obtain through DFT calculations the synthesis protocol of a MIP for levobunolol testing different functional monomers (FMs), solvents, and cross-linker agents (CLAs). The analysis of structural and energetic data led to the identification of the optimal MIP synthesis parameters, which involves the use of (trifluoromethyl)-arylic acid (TFMAA) as the functional monomer, toluene and chloroform as the solvents, and pentaerythritol triacrylate (PETRA) as the cross-linking agent. This rational design offers valuable insights for experimentalists seeking to efficiently synthesize a MIP for this important β-blocker drug.

METHODS

DFT calculations were conducted using the B97D functional along with the Pople's split valence 6-31G(d,p) basis set, which includes polarization functions on all atoms (B97D/6-31G(d,p)).

Atenolol-imprinted polymer: a DFT study

The purpose of this work was to investigate, via DFT calculations, the molecularly imprinted polymer (MIP) for atenolol (ATL) β-blocker evaluating distinct functional monomers (FMs), solvents, and cross-linker agents (CLAs). As the main result, we could determine from structural and thermodynamic data the best MIP synthesis protocol as being: p-vinyl benzoic acid (APV) as FM, toluene as solvent, and pentaerythritol triacrylate (PETRA) as CLA. We believe this rational design can be very useful for experimentalists in an attempt to perform an efficient synthesis of a MIP for this important β-blocker drug.

Green Extraction Techniques as Advanced Sample Preparation Approaches in Biological, Food, and Environmental Matrices: A Review

Green extraction techniques (GreETs) emerged in the last decade as greener and sustainable alternatives to classical sample preparation procedures aiming to improve the selectivity and sensitivity of analytical methods, simultaneously reducing the deleterious side effects of classical extraction techniques (CETs) for both the operator and the environment. The implementation of improved processes that overcome the main constraints of classical methods in terms of efficiency and ability to minimize or eliminate the use and generation of harmful substances will promote more efficient use of energy and resources in close association with the principles supporting the concept of green chemistry. The current review aims to update the state of the art of some cutting-edge GreETs developed and implemented in recent years focusing on the improvement of the main analytical features, practical aspects, and relevant applications in the biological, food, and environmental fields. Approaches to improve and accelerate the extraction efficiency and to lower solvent consumption, including sorbent-based techniques, such as solid-phase microextraction (SPME) and fabric-phase sorbent extraction (FPSE), and solvent-based techniques (μQuEChERS; micro quick, easy, cheap, effective, rugged, and safe), ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE), in addition to supercritical fluid extraction (SFE) and pressurized solvent extraction (PSE), are highlighted.

A Review on Molecularly Imprinted Polymers Preparation by Computational Simulation-Aided Methods

Molecularly imprinted polymers (MIPs) are obtained by initiating the polymerization of functional monomers surrounding a template molecule in the presence of crosslinkers and porogens. The best adsorption performance can be achieved by optimizing the polymerization conditions, but this process is time consuming and labor-intensive. Theoretical calculation based on calculation simulations and intermolecular forces is an effective method to solve this problem because it is convenient, versatile, environmentally friendly, and inexpensive. In this article, computational simulation modeling methods are introduced, and the theoretical optimization methods of various molecular simulation calculation software for preparing molecularly imprinted polymers are proposed. The progress in research on and application of molecularly imprinted polymers prepared by computational simulations and computational software in the past two decades are reviewed. Computer molecular simulation methods, including molecular mechanics, molecular dynamics and quantum mechanics, are universally applicable for the MIP-based materials. Furthermore, the new role of computational simulation in the future development of molecular imprinting technology is explored.