Polymer monolithic methacrylate base modified with tosylated-polyethylene glycol monomethyl ether as a stationary phase for capillary liquid chromatography

Effect of polyethylene glycol on polysaccharides: From molecular modification, composite matrixes, synergetic properties to embeddable application in food fields

Polyethylene glycol (PEG) is a flexible, water-soluble, non-immunogenic, as well as biocompatible polymer, and it could synergize with polysaccharides for food applications. The molecular modification strategies, including covalent bond interactions (amino groups, carboxyl groups, aldehyde groups, tosylate groups, etc.), and non-covalent bond interactions (hydrogen bonding, electrostatic interactions, etc.) on PEG molecular chains are discussed. Its versatile structure, group modifiability, and amphiphilic block buildability could improve the functions of polysaccharides (e.g., chitosan, cellulose, starch, alginate, etc.) and adjust the properties of combined PEG/polysaccharides with outstanding chain tunability and matrix processability owing to plasticizing effects, compatibilizing effects, steric stabilizing effects and excluded volume effects by PEG, for achieving the diverse performance targets. The synergetic properties of PEG/polysaccharides with remarkable architecture were summarized, including mechanical properties, antibacterial activity, antioxidant performance, self-healing properties, carrier and delivery characteristics. The PEG/polysaccharides with excellent combined properties and embeddable merits illustrate potential applications including food packaging, food intelligent indication/detection, food 3D printing and nutraceutical food absorption. Additionally, prospects (like food innovation and preferable nutrient utilization) and key challenges (like structure-effectiveness-applicability relationship) for PEG/polysaccharides are proposed and addressed for food fields.

A polyethyleneimine-functionalized polymer substrate polar stationary phase

A polyethyleneimine (PEI)-functionalized polymer substrate polar stationary phase was prepared for hydrophilic interaction chromatography (HILIC) by grafting PEI onto poly(styrene-divinylbenzene) (PS-DVB) microspheres. The phase shows a U-shape retention profile and it exhibits typical hydrophilic characteristic when the organic solvent fraction in the mobile phase is > 60%. Hydrogen bonding, anion exchange, and hydrophobic interaction are involved in the retention mechanism. Good separation and unique selectivity for acidic, basic and neutral polar analytes were achieved. It showed extremely low column bleed (comparable to that of blank) under gradient elution mode (even to 50% fraction of water) and wide pH tollerance range (at least 1-13).

Poly(ethylene glycol) Methyl Ether Methacrylate-bonded Stationary Phase in Ion Chromatography and Its Application to Seawater Samples

A fast and simple ion chromatographic method for the determination of iodide in seawater is reported using poly(ethylene glycol) methyl ether methacrylate-bonded stationary phase. Poly(ethylene glycol) methyl ether methacrylate was reacted with primary amino groups of aminopropylsilica in N,N-dimethylformamide at 80°C. The prepared stationary phases were evaluated by analyzing several inorganic anions and the retention behavior was observed. Various chromatographic parameters were optimized for the separation of these anions. Although there were no ion-exchange sites on the resulted stationary phases, the results obtained suggested that an ion-exchange mechanism was involved in the retention of analyte anions. With 0.15 μL injection, the limit of quantitation of iodide was 26 μg L^-1 when 200 mM NaCl was selected as the eluent. This stationary phase was applied to the analysis of direct and fast determination of iodide in real seawater samples successfully with the recovery rates of 98.1 and 104.9%.

Separation of Inorganic Anions Using an 18-Crown-6-ether-modified Organic Polymer Monolithic Stationary Phase in Capillary Ion Chromatography

In this study, a monolithic organic polymer stationary phase was modified using 18-crown-6-ether for use in capillary ion chromatography. Its use in the separation of inorganic anions was investigated. The monolithic stationary phase was obtained by chemically bonding 2-aminomethyl-18-crown-6-ether to a polymer skeleton comprising glycidyl methacrylate and ethylene glycol dimethacrylate. The optimum level of the loading of 2-aminomethyl-18-crown-6-ether onto the stationary phase was investigated. The resulting stationary phase was used to investigate the influence of the eluent cation, the concentration of the eluent, and the pH of the eluent on the separation of inorganic anions.

Silica Nanoparticles

Silica consists of one silicon atom and two oxygen atoms (SiO₂) and is commonly used in various aspects of daily life. For example, it has been used as glass, insulator, and so on. Nowadays, silica is used as core reagents for fabricating and encapsulating nanoparticles (NPs). In this chapter, the usage of silica in nanotechnology is described. Synthesis and surface modification of silica nanoparticles (SiNPs), including via the Stöber method, reverse microemulsion method, and modified sol-gel method, are illustrated. Then, various NPs with silica encapsulation are explained. At last, the biological applications of those mentioned NPs are described.

A novel photoluminescence sensing system sensitive for and selective to bromate anions based on carbon dots

A simple, highly sensitive and selective PL sensing method for bromate anions has been developed.