High Internal Phase Emulsion Polymeric Monolith Extraction Coupling with High-Performance Liquid Chromatography for the Determination of Para Red and Sudan Dyes in Chilli Samples

Magnetic solid phase extraction and determination of polychlorinated biphenyls in beverages utilizing C60 modified magnetic polyamido-amine dendrimers in combination with gas chromatography-tandem mass spectrometry

Polychlorinated biphenyls (PCBs) are persistent organic pollutants which are widely present in environment and harmful to human health. In this study, an efficient and convenient magnetic solid phase extraction method with C₆₀ modified magnetic polyamido-amine (PAMAM) dendrimers as sorbents was established for enriching trace amounts of PCBs in beverage samples. Gas chromatography-tandem mass spectrometry (GC-MS/MS) was utilized for analysis of PCBs. Parameters affecting extraction efficiency were optimized. Under optimal parameters, good linearity can be achieved in concentration range of 0.001-20 μg L^-1 and 0.002-20 μg L^-1 for nine selected PCBs. The limits of detection for PCBs were in the range of 0.1-0.2 ng L^-1. The spiked recoveries were in the range of 87.0 %-115.1 % (n = 3). The results proved that this established method was reliable for monitoring trace PCBs in beverage samples.

Magnetic solid phase extraction of heterocyclic aromatic hydrocarbons from environmental water samples with multiwalled carbon nanotube modified magnetic polyamido-amine dendrimers prior to gas chromatography-triple quadrupole mass spectrometer

Present study described a sensitive and efficient method for determination of heterocyclic aromatic hydrocarbons using multiwalled carbon nanotubes modified magnetic polyamido-amine dendrimers (MNPs@PAMAM-Gn@MWCNTs) as adsorbent for magnetic solid-phase extraction (MSPE) coupled with gas chromatography-triple quadrupole mass spectrometer (GC-MS/MS). Some pivotal parameters including PAMAM generation, adsorbent dosage, adsorption time, elution time and volume, pH and humic acid concentration were investigated to achieve the best adsorption efficiencies. Under the optimal conditions, 7-methylquinoline, dibenzothiophene and carbazole had good linearity in the concentration range of 0.005-20 μg L ^- 1, 9-methylcarbazole, 4-methyldibenzothiophene and 4,6-dimethyl dibenzothiophene had good linearity in the concentration range of 0.001-20 μg L ^- 1. All the correlation coefficients were higher than 0.996. The detection limits of the targets were in the range of 2.2 × 10^-4-1.8 × 10^-3 μg L ^- 1 with precisions less than 8.28% (n = 6). The enrichment factors were in the range of 141-147. The spiked recoveries were in the range of 87.0%-115.1% (n = 3). These results indicated that the method could be a reliable alternative tool for monitoring trace heterocyclic aromatic hydrocarbons in environmental water samples.

Recent advances in separation applications of polymerized high internal phase emulsions

Polymerized high internal phase emulsions as highly porous adsorption materials have received increasing attention and wide applications in separation science in recent years due to their remarkable merits such as highly interconnected porosity, high permeability, good thermal and chemical stability, and tailorable chemistry. In this review, we attempt to introduce some strategies to utilize polymerized high internal phase emulsions for separation science, and highlight the recent advances made in the applications of polymerized high internal phase emulsions for diverse separation of small organic molecules, carbon dioxide, metal ions, proteins, and other interesting targets. Potential challenges and future perspectives for polymerized high internal phase emulsion research in the field of separation science are also speculated at the end of this review.

Functional macroporous amphoteric polyelectrolyte monoliths with tunable structures and properties through emulsion-templated synthesis

HYPOTHESIS

Macroporous polyampholyte hydrogels, simultaneously bearing both the anionic and cationic groups, demonstrate immense promise over the one-sign charged polyelectrolytes, owing to a unique phenomenon known as the ˝anti-polyelectrolyte˝ effect. Thus, they are extremely promising materials, since they remain solvated and functional even in harsh conditions. Furthermore, macroporous morphology significantly enhances polyampholyte response to external stimuli, since it accelerates the solvent transport through the hydrogel.

EXPERIMENTS

A new templated-synthesis through "HIPE mixtures" is reported, where the two pre-formed high internal phase emulsions (HIPE) containing the oppositely charged monomers (2-acrylamido-2-methyl-1-propanesulfonic acid and (3-acrylamidopropyl)trimethylammonium chloride) were combined in the same mould, which after polymerization result in the formation of macroporous monoliths of different structures. The resulting frameworks were either copolymer or dual homopolymers in the form of bilayered or mixed porous structures.

FINDINGS

The co- and mixed-amphoteric polyelectrolytes exhibit 'anti-polyelectrolyte' behaviour typical of polyampholytes, while the bilayered-structure behaves like a typical polyelectrolyte. Complete and simultaneous removal of both dyes from a dye mixture was observed for the bilayered- and mixed-amphoteric polyelectrolyte, while copoly-ampholyte showed only partial dye adsorption. These results clearly reveal the benefits of a mutual combination of the HIPE-templated structure and the oppositely charged amphoteric nature in one-piece material as a promising avenue toward advanced materials.

Challenges and Advances in the Fabrication of Monolithic Bioseparation Materials and their Applications in Proteomics Research

High-performance liquid chromatography integrated with tandem mass spectrometry (HPLC-MS/MS) has become a powerful technique for proteomics research. Its performance heavily depends on the separation efficiency of HPLC, which in turn depends on the chromatographic material. As the "heart" of the HPLC system, the chromatographic material is required to achieve excellent column efficiency and fast analysis. Monolithic materials, fabricated as continuous supports with interconnected skeletal structure and flow-through pores, are regarded as an alternative to particle-packed columns. Such materials are featured with easy preparation, fast mass transfer, high porosity, low back pressure, and miniaturization, and are next-generation separation materials for high-throughput proteins and peptides analysis. Herein, the recent progress regarding the fabrication of various monolithic materials is reviewed. Special emphasis is placed on studies of the fabrication of monolithic capillary columns and their applications in separation of biomolecules by capillary liquid chromatography (cLC). The applications of monolithic materials in the digestion, enrichment, and separation of phosphopeptides and glycopeptides from biological samples are also considered. Finally, advances in comprehensive 2D HPLC separations using monolithic columns are also shown.