Dual chiral selectors modified magnetic particles for enantioseparation of tryptophan and mandelic acid enantiomers in aqueous medium

A Critical Review of Analytical Applications of Chitosan as a Sustainable Chemical with Functions Galore

Biomass and biowastes stand as sustainable and cost-effective environmentally benign alternative feedstock. Chitosan is a biocompatible, bioactive, and biodegradable biopolymer derived from chitin to achieve eight aspects out of the 12 green chemistry principles. Chitosan got significant attention in several fields including chemical analysis, in addition to chemical functionally, which enabled its use as adsorbent and its structural crosslinking using various crosslinkers. The physicochemical, technological, and optical properties of chitosan have been extensively exploited in analysis. Mainly, deacetylation degree and molecular weight are controlling its properties and hence controlling its functions. This review presents a structure, properties, and functions relationships of chitosan. It also aims to provide an overview of the different functions that chitosan can serve in each analytical technique such as supporting matrix, catalyst…etc. The contribution of chitosan in improving the ecological performance is discussed in each technique.

Enantioselective chitosan-based racemic ketoprofen imprinted polymer: Chiral recognition and resolution study

This work presented a novel racemic imprinting process employing the chiral properties of chitosan monomer. The preparation of racemic ketoprofen (RS-KTP) imprinted polymer (RS-MIP) was conducted using glutaraldehyde as a crosslinker. The nature of elution solvent affected the % desorption ratio suggesting a heterogenous nature of the formed binding sites. Good imprinting was indicated by an imprinting factor of 3.50 for S-KTP. The enantioselectivity of the RS-MIP was indicated by enantioselectivity coefficient of 2.31 and % enantiomeric excess (%ee) of 28.55%. A SPE cartridge packed with RS-MIP enabled resolution of RS-KTP using gradient elution solvent system. Scatchard plot revealed two binding sites types of different affinity towards S-KTP and density observed for the RS-MIP. The binding capacity of RS-MIP showed observed dependence on the % ee of S-KTP indicating its enantioselectivity. The success of using racemic template for the preparation of enantioselective MIP brings a new possibility to achieve enantioseparation of racemic mixtures having very expensive or unavailable pure enantiomers.

Effects of four drying methods on Amomum villosum Lour. ‘Guiyan1’ volatile organic compounds analyzed via headspace solid phase microextraction and gas chromatography-mass spectrometry coupled with OPLS-DA

This paper analyzed the effects of four drying methods (heat pump drying, hot air drying, sun drying, and freeze drying) on the volatile organic compounds (VOCs) in fresh ‘Guiyan1’ Amomum villosum Lour. Via separation, component differentiation, and overall variance analysis via HS-SPME-GC/MS coupled with OPLS-DA, 133 kinds of VOCs, mainly composed of hydrocarbons, esters, and alcohols, were identified. The differences in ‘Guiyan1’ processed by freeze-drying and the other three drying methods were the most significant and easily distinguishable. The main VOCs in the dried samples were bornyl acetate and 2-bornanone, with the largest increase in 2-bornanone and the largest decrease in bicyclogermacrene. The obtained data provided guidance for optimizing the processing and storage of ‘Guiyan1’.

This paper analyzed the effects of four drying methods (heat pump drying, hot air drying, sun drying, and freeze drying) on the volatile organic compounds (VOCs) in fresh ‘Guiyan1’ Amomum villosum Lour.