Microporous polymer microspheres with amphoteric character for the solid-phase extraction of acidic and basic analytes

Extraction of selected benzothiazoles, benzotriazoles and benzenesulfonamides from environmental water samples using a home-made sol-gel silica-based mixed-mode zwitterionic sorbent modified with graphene

A novel sol-gel silica-based mixed-mode zwitterionic sorbent modified with graphene microparticles was synthesized. Thanks to the inclusion of multiple functional groups and graphene microparticles to exert a wide range of intermolecular/interionic interactions including dipole-dipole interactions, ion-exchange interactions and π-π interactions, the sorbent showed high retention in the solid-phase extraction (SPE) of benzothiazoles, benzotriazoles and benzenesulfonamides. The SPE protocol was optimized in terms of pH, sample loading volume and elution conditions using liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS). The method based on SPE followed by LC-HRMS was validated. Apparent recoveries at two levels of concentration were in the range from 48 to 85% (in most cases) in matrices such as influent wastewater, matrix effect was lower than ±30% in most cases, method detection and quantification limits being lower than 20 ng/L and repeatability and reproducibility between days were lower than 18% (n = 4). River, effluent and influent wastewaters samples were analyzed, obtaining concentrations ranging from 3 to 175 ng/L in river samples, from 12 to 499 ng/L in effluent samples and from 15 to 632 ng/L in influent samples, when the compounds were above the method quantification limits.

A novel method based on solid phase extraction and liquid chromatography-tandem mass spectrometry warrants occurrence of trace xanthates in water

Huge volumes of wastewater containing organic flotation reagents such as xanthates have been released into the environment via mining activities, greatly threatening the eco-environment safety. A simple and fast method is urgently needed for accurate analysis of various xanthates in mining and environmental water. Here, a robust method is realized for simultaneous determination of three trace xanthates (i.e., potassium ethyl xanthate, potassium butyl xanthate, and potassium isopropyl xanthate) in environmental water samples, including eutrophic water and flotation wastewater using solid phase extraction (SPE) and HPLC-MS/MS. HPLC-MS/MS parameters, SPE cartridges and eluting solvents, pH values, and SPE procedures were optimized. The new method had an excellent linearity in the range of 1-1000 μg/L (R² ≥ 0.998), low limits of detection (0.02-0.68 μg/L), and satisfactory accuracy and precision (72.9%-107.6% of average recoveries and <5% of relative standard deviations at 1, 10, 50, and 500 μg/L of xanthates). This is a first method developed for determination of trace xanthates in water samples. It was successfully applied to determine the target analytes in outdated flotation wastewater and river water samples, warranting the occurrence of trace xanthates (0.13-16.9 μg/L) in water and necessity of systematic investigation on environmental fate and risk of xanthates.

Preparation and application of nano petal-shaped covalent organic frameworks modified polystyrene-divinylbenzene- glycidylmethacrylate microspheres for the extraction of illicit drugs from wastewater

A novel nano petal-shaped covalent organic frameworks modified magnetic polystyrene-divinylbenzene-glycidylmethacrylate (NP-COF@Mag-PS/DVB/GMA) microsphere has been synthesized. It is a perfect combination of high productivity of PS/DVB/GMA microspheres and excellent enrichment efficiency of COF particles, and the excellent properties of NP-COF@Mag-PS/DVB/GMA microspheres are characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) and X-ray photoelectron spectroscopy (XPS). The sorbent can extract illicit drugs via the reverse-phase interactions provided by benzene ring on the polymer backbone and the hydrogen bonding interactions provided by functional group (-NH-) on the COF particles. Based on using NP-COF@Mag-PS/DVB/GMA as sorbents, an easiness-to-handle of magnetic dispersive solid phase extraction (Mag-dSPE) procedure is proposed for the simultaneous preconcentration of 12 illicit drugs from wastewater. The obtained results show high extraction efficiency of NP-COF@Mag-PS/DVB/GMA to illicit drugs with recoveries between 81.6 and 116%. Furthermore, a liquid chromatography-tandem quadrupole mass spectrometry (LC-MS/MS) method for the determination of 12 illicit drugs from wastewater at sub-ppt levels has been proposed and validated with the pretreatment of samples by Mag-dSPE. The limits of quantification (LOQs) for the 12 illicit drugs are between 0.40 and 4.90 ng/L. Validation results on linearity, specificity, trueness and precision, as well as on application to the analysis of 12 illicit drugs in ten real samples demonstrate the applicability to environment monitoring analysis.

Development of sol-gel silica-based mixed-mode zwitterionic sorbents for determining drugs in environmental water samples

Four novel mixed-mode zwitterionic silica-based functionalized with strong moieties sorbents were synthesized and evaluated through solid-phase extraction (SPE) to determine acidic and basic drugs in environmental water samples. All sorbents had the same functionalization: quaternary amine and sulfonic groups and C₁₈ chains so that hydrophobic and strong cationic exchange (SCX) and strong anionic exchange (SAX) interactions could be exploited, in addition, two of them had carbon microparticles embedded. All sorbents retained both acidic and basic compounds in the preliminary assays but only the basic compounds were retained selectively through ionic exchange interactions when a clean-up step was introduced. The SPE method was therefore optimized to promote the selective retention of the basic compounds, initially with the two best-performing sorbents. After optimization of the SPE protocol, these sorbents were evaluated for the analysis of environmental water samples using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method with the best-performing sorbent was then validated with 100 mL of river samples and 50 mL of effluent wastewater samples in terms of apparent recoveries (%R_app) spiking samples at 50 ng/L (river) and 200 ng/L (river and effluent), matrix effect, linear range, method quantification and detection limits, repeatability, and reproducibility. It should be highlighted that %R_app ranged from 40 to 85% and matrix effects ranged from -17 to -4% for spiked river samples. When the method was applied to river and effluent wastewater samples, most compounds were found in the range from 24 to 1233 ng/L with detection limits from 1 to 5 ng/L.

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.

Dual mixed-mode poly (vinylpyridine-co-methacrylic acid-co-ethylene glycol dimethacrylate)-based sorbent for acidic and basic drug extraction from oral fluid samples

In this study, a dual mixed-mode polymer sorbent was prepared via one-step thermally initiated polymerization of 4-vinylpyridine (VP), methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) for the solid-phase extraction (SPE) of basic and acidic drugs. The use of VP and MAA as ionizable functional monomers allowed the tailoring of ion-exchange and hydrophobic features of the polymer. The obtained polymer was characterized by Fourier-transform infrared spectroscopy and scanning electron microscopy. Next, the retention behavior of dual mixed-mode polymer towards basic and acidic drugs was investigated. Moreover, the practical capability of this novel material was tested for the extraction of relevant drugs such as cocaine, 3-methylmethcathinone, and diazepam in oral fluid samples. Recovery values (at different spiked levels in blank oral fluid samples), ranging from 69 to 99%, and limits of detection (LODs), between 0.10 and 0.25 μg L^-1, were obtained.

Application of amphoteric polymers in the process of leather post-tanning

Abstract

With the characteristics of controllable charge and environmental friendliness, amphoteric polymers can be used in post-tanning process to solve the problems that arise during leather making and are caused by the low absorption rate of single-charge chemicals, incompatibility with new tanning methods, and complex operation process. In this review, the structure, performance, and preparation of amphoteric polymers are reported. Then, the charge change of collagen during different tanning and pH treatments is introduced. Finally, the application and development of amphoteric polymers during the post-tanning process of leather making are discussed. This review has certain guiding significance to the preparation and application of amphoteric polymers for tanning system.

Graphical abstract