Hypercrosslinked strong anion-exchange resin for extraction of acidic pharmaceuticals from environmental water

Preparation of amine-modified amphiphilic resins for the extraction of trace pharmaceuticals and personal care products in environmental waters

Herein, four amine-modified amphiphilic resins were synthesized and utilized as solid-phase extraction (SPE) materials to enrich pharmaceuticals and personal care products (PPCPs) from environmental water. The obtained materials (Strong anion-exchange amphiphilic materials, SAAMs; Weak anion-exchange amphiphilic materials, WAAMs) possessed large specific surface area (473-626 m²/g), high ion exchange capacity (0.89-1.97 mmol/g), and small contact angle (74.41-79.74°), indicating good hydrophilicity. The main factors affecting the efficiency of the extraction process were studied, including column volume, column flow rate, sample salinity and sample pH. Notably, the trend observed in absolute recovery was significantly correlated with the Zeta potential of the employed adsorbents. Furthermore, based on the obtained materials, a method of SPE coupled with ultra-performance liquid chromatography and tandem mass spectrometry (SPE/LC-MS/MS) was developed, and then utilized to determine PPCPs in the samples collected from the Yangtze River Delta. The Method detection limit (MDL) and Method quantification limit (MQL) ranged from 0.05 to 0.60 ng/L and 0.17 to 2.00 ng/L, respectively, with a relative standard deviation (RSD) below 6.3%, demonstrating good accuracy and sensitivity. As evidenced by comparison with previous literature, the developed method exhibited satisfactory performance, showing great potential for further commercial application in the extraction of trace PPCPs from environmental water samples.

Weak anion-exchange mixed-mode materials to selectively extract acidic compounds by stir bar sorptive extraction from environmental waters

In this study, the first example of a polytetrafluoroethylene (PTFE)-based magnet coated with weak anion exchange (WAX) monolith as novel support for stir bar sorptive extraction (SBSE) is presented. Firstly, the PTFE magnets were properly modified and vinylized in order to immobilize polymer monoliths onto its surface. Then, a glycidyl methacrylate monolith was prepared and modified with ethylenediamine (EDA) to create weak anion exchanger via ring opening reaction of epoxy groups. The prepared covalently immobilized EDA-modified monoliths onto PTFE magnet exhibited good stability and reusability. Application of resulting material as stir bar for SBSE was investigated for a series of acidic compounds that includes acesulfame, saccharin, diclofenac or ibuprofen, among others as target compounds. Firstly, the SBSE conditions were optimized to promote the WAX interactions with the target compounds achieving recoveries from 37 to 75% and enable the selective extraction of these compounds as it provided values of% matrix effect from 17 to -13% when they were determined by SBSE followed by liquid chromatography - tandem mass spectrometry. The analytical methodology, was then validated and applied for the determination of the target solutes in environmental water samples, which were found at concentration up to 2500 ng L^-1 in river waters.

Hypercrosslinked polymer microspheres decorated with anion- and cation-exchange groups for the simultaneous solid-phase extraction of acidic and basic analytes from environmental waters

Mixed-mode ion-exchange sorbents were introduced to improve the selectivity and retention of solid-phase extraction (SPE) sorbents. Mixed-mode ion-exchange sorbents integrate reversed-phase chemistry with ion-exchange groups to promote favourable interactions with ionic species. Nevertheless, a need to extract analytes with acidic and basic properties simultaneously within the same SPE cartridge led to the introduction of novel amphoteric/zwitterionic sorbents, which incorporate cation- and anion-exchange moieties within the same functional group attached to the polymeric network. In the present study, the development, preparation and SPE evaluation of two novel hypercrosslinked zwitterionic polymeric sorbents, functionalised with either strong anion-exchange (SAX) and weak cation-exchange (WCX) or weak anion-exchange (WAX) and strong cation-exchange (SCX) groups (namely HXLPP-SAX/WCX and the HXLPP-WAX/SCX), is presented for the simultaneous retention of acidic and basic compounds. The sorbents were prepared by a precipitation polymerisation route which yielded poly(divinylbenzene-co-vinylbenzylchloride) as a precursor polymer; subsequently, the precursor polymer was hypercrosslinked, to increase the specific surface areas and capacities of the sorbents, and then functionalised to impart the zwitterionic character. The HXLPP-SAX/WCX sorbent was decorated with quaternised sarcosine groups and the HXLPP-WAX/SCX sorbent was decorated with taurine moieties. The SPE parameters were optimised to exploit the ionic interactions between compounds and the functional groups. The optimal conditions involve a washing step to remove the compounds retained by hydrophobic interactions, thus increasing the selectivity. The optimised SPE protocol used the quaternised sarcosine-based sorbent followed by liquid chromatography and tandem mass spectrometry, and was applied to determine compounds with acidic and basic properties from environmental samples, such as river water and effluent wastewater samples, with excellent selectivity and matrix effect values below -30% and apparent recovery results ranging from 52% to 105% for most of the compounds. The analytical method was validated for environmental water samples and used in the analysis of samples in which some of the target compounds were found at ng L^-1 concentration levels.

Development of a maleic acid-based material to selectively solid-phase extract basic compounds from environmental samples

This study presents a novel mixed-mode weak cation-exchange (WCX) material. This material was prepared by means of the functionalization of a mesoporous divinylbenzene (DVB) resin with maleic acid (maleic acid-DVB), which yielded a high carboxylic moiety content resulting in WCX interactions as well as suitable specific surface area for reversed-phase interactions. After the optimization of the solid-phase extraction (SPE) protocol to enhance the selectivity of the sorbent, this material was evaluated as a novel WCX sorbent in the SPE of a group of drugs from environmental water samples. The method is based on SPE followed by liquid chromatography (LC) coupled to high resolution mass spectrometry (HRMS) with an Orbitrap analyzer, and was validated and applied for the determination of basic drugs in river, effluent and influent wastewater samples. Maleic acid-DVB sorbent yielded suitable recovery rates (57% to 89%) and an acceptable matrix effect (<32%) thanks to the effective washing step included when these environmental waters were loaded through the novel resin. The method was applied to different environmental water samples and some basic drugs were suitably quantified in these environmental samples.

Extraction and purification of ustiloxin A from rice false smut balls by a combination of macroporous resin and high-speed countercurrent chromatography

Abstract

Rice false smut is an emerging plant disease worldwide. Ustiloxin A (UstA) is the major mycotoxin found in rice false smut balls, which are fungal colonies in rice florets. In this study, a new method consisting of macroporous resin column chromatography and high-speed countercurrent chromatography (HSCCC) was developed for UstA separation. UstA was extracted by a 3.81% HCOOH solution and adsorbed by XAD-4 resin. UstA was then eluted by a 40% methanol solution supplemented with 0.1% trifluoroacetic acid (TFA). Further purification was achieved by HSCCC using a two-phase solvent system consisting of n-butanol/TFA/H2O (1/0.05/1, v/v/v). Under the optimized conditions, 225 mg of UstA was obtained with a purity of 97.39% in a single run, with a final recovery of 65.2%. An inhibitory effect on seed germination of wheat and maize caused by UstA was observed in a preliminary phytotoxicity assay.

Graphical abstract

The synthesis and characterisation of porous and monodisperse, chemically modified hypercrosslinked poly(acrylonitrile)-based terpolymer as a sorbent for the adsorption of acidic pharmaceuticals

The synthesis and characterization of porous poly(acrylonitrile(AN)-co-divinylbenzene-80 (DVB-80)-co-vinylbenzylchloride (VBC)) polymers with high specific surface areas and weak anion-exchange character have been successfully researched. The hypercrosslinked (HXL) microspheres were chemically modified with 1,2-ethylenediamine (EDA) to enhance the adsorption selectivity of the HXL materials. The zeta potential of EDA-modified HXL poly(AN-co-DVB-80-co-VBC) revealed that the surface of the modified terpolymer was positively charged. The FT-IR spectra of the chemically modified hypercrosslinked poly(AN-co-DVB-80-co-VBC) showed that the nitrile groups derived from the AN unit were utilised by the presence of diamine groups. The BET-specific surface areas of the EDA-modified hypercrosslinked poly(AN-co-DVB-80-co-VBC) was 503 m2 g−1; meanwhile, the specific surface area of the HXL terpolymer was 983 m2 g−1. The adsorption isotherm data were well fitted by both the Langmuir and Freundlich models, whereas the adsorption kinetics followed the pseudo-second-order kinetic model. This study confirms that the EDA-modified hypercrosslinked poly(AN-co-DVB-80-co-VBC) terpolymer is a potential adsorbent for the adsorption of acidic pharmaceuticals.

Optimization of l-arginine purification from Corynebacterium crenatum fermentation broth

l-Arginine has many special physiological and biochemical functions, with wide applications in the food and pharmaceutical industry. Few studies on the purification of l-arginine from fermentation broth have been conducted; however, none of them were systematic enough for industrial scale-up. Therefore, it is necessary to develop a highly efficient and systematic process for the purification of l-arginine from fermentation broth. In this study, we screened out a cation exchange resin, D155, having high exchange capacity, high selectivity, and easy elution capacity, and analyzed its adsorption isotherm, thermodynamics, and kinetics using different models. Further, the process parameters of fixed-bed ion exchange adsorption and elution were optimized, and the penetration curve during the operation was modeled. Based on the fixed-bed ion-exchange parameters, a 30-column continuous ion-exchange system was designed, and the flow velocity in each zone was optimized. Finally, to obtain a high purity of l-arginine, the purification tests were conducted using anion exchange resin 711, and an l-arginine yield of 99.1% and purity of 98.5% was obtained. This effective and economical method also provides a promising strategy for separation of other amino acids from the fermentation broth, which is of great significance to the l-arginine fermentation industry.

Dispersible microporous diblock copolymer nanoparticles via polymerisation-induced self-assembly

Dispersible microporous polymer nanoparticles formed via the RAFT-PISA polymerisation of divinylbenzene and fumaronitrile using a PEG macro-CTA.

Hypercrosslinked porous polymer materials: design, synthesis, and applications

Hypercrosslinked polymers (HCPs) are a series of permanent microporous polymer materials initially reported by Davankov, and have received an increasing level of research interest. In recent years, HCPs have experienced rapid growth due to their remarkable advantages such as diverse synthetic methods, easy functionalization, high surface area, low cost reagents and mild operating conditions. Judicious selection of monomers, appropriate length crosslinkers and optimized reaction conditions yielded a well-developed polymer framework with an adjusted porous topology. Post fabrication of the as developed network facilitates the incorporation of various chemical functionalities that may lead to interesting properties and enhance the selection toward a specific application. To date, numerous HCPs have been prepared by post-crosslinking polystyrene-based precursors, one-step self-polycondensation or external crosslinking strategies. The advent of these methodologies has prompted researchers to construct well-defined porous polymer networks with customized micromorphology and functionalities. In this review, we describe not only the basic synthetic principles and strategies of HCPs, but also the advancements in the structural and morphological study as well as the frontiers of potential applications in energy and environmental fields such as gas storage, carbon capture, removal of pollutants, molecular separation, catalysis, drug delivery, sensing etc.

Rapid magnetic solid-phase extraction of Congo Red and Basic Red 2 from aqueous solution by ZIF-8@CoFe2 O4 hybrid composites

Core-shell metal-organic framework materials have attracted considerable attention mainly due to their enhanced or new physicochemical properties compared with their single-component counterparts. In this work, a core-shell heterostructure of CoFe2 O4 -Zeolitic Imidazolate Framework-8 (ZIF-8@CoFe2 O4 ) is successfully fabricated and used as an solid-phase extraction adsorbent to efficiently extract Congo Red and Basic Red 2 dyes from contaminated aqueous solution. Vibrating sample magnetometry indicates that the saturated magnetization of ZIF-8@CoFe2 O4 is 3.3 emu/g, which is large enough for magnetic separation. The obtained hybrid magnetic metal-organic framework based material ZIF-8@CoFe2 O4 can remove the investigated dyes very fast within 1 min of the contact time. The adsorbent ZIF-8@CoFe2 O4 also shows a good reusability. After regeneration, the adsorbent can still exhibit high removal efficiency (∼97%) toward Congo Red for five cycles of desorption-adsorption. This work reveals the great potential of core-shell ZIF-8@CoFe2 O4 sorbents for the fast separation and preconcentration of organic pollutants in aqueous solution before high-performance liquid chromatography analysis.

The effect of molecular weight on the porosity of hypercrosslinked polystyrene

Microporous polymers can be prepared by crosslinking polystyrenes, with the surface areas being dependent on the degree of polymerisation.

Hypercrosslinked materials: preparation, characterisation and applications

Hypercrosslinked materials have experienced a great expansion in both the synthetic approach and the field of applications.