Stir bar sorptive-dispersive microextraction by a poly(methacrylic acid-co-ethylene glycol dimethacrylate)-based magnetic sorbent for the determination of tricyclic antidepressants and their main active metabolites in human urine

A poly(methacrylic acid-co-ethylene glycol dimethacrylate)-based magnetic sorbent was used for the rapid and sensitive determination of tricyclic antidepressants and their main active metabolites in human urine. This material was characterized by magnetism measurements, zeta potential, scanning electron microscopy, nitrogen adsorption–desorption isotherms, and thermogravimetric analysis. The proposed analytical method is based on stir bar sorptive-dispersive microextraction (SBSDME) followed by liquid chromatography–tandem mass spectrometry. The main parameters involved in the extraction step were optimized by using the response surface methodology as a multivariate optimization method, whereas a univariate approach was employed to study the desorption parameters. Under the optimized conditions, the proposed method was properly validated showing good linearity (at least up to 50 ng mL−1) and enrichment factors (13–22), limits of detection and quantification in the low ng L−1 range (1.4–7.0 ng L−1), and good intra- and inter-day repeatability (relative standard deviations below 15%). Matrix effects were observed for the direct analysis of urine samples, but they were negligible when a 1:1 v/v dilution with deionized water was performed. Finally, the method was successfully applied to human urine samples from three volunteers, one of them consuming a prescribed drug for depression that tested positive for clomipramine and its main active metabolite. Quantitative relative recoveries (80–113%) were obtained by external calibration. The present work expands the applicability of the SBSDME to new analytes and new types of magnetic sorbents. Graphical abstract

Noncovalently D-arabinitol Molecularly Imprinted Polymers (MIPs) to Identify Different Sugar Alcohols

Molecularly imprinted polymers (MIPs) are an effective method for separating enantiomeric compounds. The main objective of this research is to synthesize D-arabinitol MIPs, which can selectively separate D-arabinitol and its potential application to differentiate it from its enantiomer compound through a non-covalent approach. A macroporous polymer was synthesized using D-arabinitol as a template, acrylamide as a functional monomer, ethylene glycol dimethacrylate (EGDMA) being a cross-linker, dimethylsulfoxide (DMSO) being a porogen, as well as benzoyl peroxide being an initiator. After polymer synthesis, D-arabinitol was removed by a mixture of methanol and acetic acid (4:1, v/v). Fourier-Transform Infrared spectroscopy (FT-IR) and Scanning Electron Microscopy (SEM) distinguished the MIPs and NIPs. A selectivity test of MIPs against its enantiomers (L-arabinitol, xylitol, adonitol, and glucose) was carried out using the batch rebinding method. The binding site was quantitatively determined using the Langmuir equation. The results of the selectivity test showed that the MIPs produced was quite selective toward its enantiomer and could potentially be used to separate D-arabinitol from its enantiomer.

Polyhedral Oligomeric Silsesquioxane Based Silicone Ophthalmic Contact Lens Material Containing Neodymium Nanoparticles

This research was conducted to analyze the compatibility of used monomers and produce the high functional POSS-based ophthalmic polymer containing silicone monomers and neodymium nanoparticle. Synthesized silicone polymer (SiD), trimethylsilylmethacrylate (TSMA), N-vinyl-2-pyrrolidone (NVP) and neodymium nanoparticles were used as additives for the basic combination of polyhedral oligomeric silsesquioxane (POSS), and methyl methacrylate (DMA). And also, the materials were copolymerized with ethylene glycol dimethacrylate (EGDMA) as the cross-linking agent, azobisisobutyronitrile (AIBN) as the initiator. It is judged that the POSS-co-NVP polymer is optically good and thus have good compatibility. Especially copolymerization with TSMA showed high oxygen permeability, but with SID considered to be more stable judging by lens shape. Physical properties shows that the neodymium nanoparticle increases the wettability while maintaining water content. These materials are considered to make synergy effect each other, so it can be used in functional hydrogel ophthalmic lenses.

Preparation and Analysis of Functional Silicone Hydrogel Lenses Containing ZrO2 and Antimony Tin Oxide Nanoparticles

This study prepared silicone hydrogel ophthalmic lenses using 2-hydroxyethylmethacrylate (HEMA), synthesized silicone monomer (SID), dimethylarsinic acid (DMA), N-hydroxyethyl acrylamide (HEA), ethylene glycol dimethacrylate (a crosslinking agent, EGDMA), and azobisisobutyronitrile (an initiator, AIBN). Also, Zirconium oxide (ZrO2), antimony tin oxide (ATO) nanoparticles were added to the silicone hydrogel material to analyze the characteristics of the nanoparticles. The mixture was heated at 130 °C for 2 hours to produce the ophthalmic contact lens by cast mould method. As a result, the manufactured silicone hydrogel lens was prepared having high oxygen permeability and tensile strength while satisfying the basic requirements of ophthalmic hydrogel lens materials. Also, the addition of ZrO2 NPs increased tensile strength of the manufactured lens, and ATO NPs were found to improve wettability. Therefore, ZrO2 and ATO nanoparticles can be used effectively as additives for functional ophthalmic silicone hydrogel lenses.