Mixed-mode ion-exchange polymeric sorbents in environmental analysis

ExpoNano: A Strategy Based on Hyper-Cross-Linked Polymers Achieves Urinary Exposome Assessment for Biomonitoring

Urinary analysis of exogenous and endogenous molecules constitutes an efficient, noninvasive approach to evaluate human health status. However, the exposome characterization of urinary molecules remains extremely challenging with current techniques. Herein, we develop an ExpoNano strategy based on hyper-cross-linked polymers (HCPs) to achieve ultrahigh-throughput measurement of exo/endogenous molecules in urine. The strategy includes a simple trapping-detrapping procedure (15 min) with HCPs in enzymatically treated urine, followed by mass spectrometer determination. Molecules that can be determined by ExpoNano have a wide range of molecular weight (75-837 Da) and Log Kow (octanol-water partition coefficient; -9.86 to 10.56). The HCPs can be repeatedly used five times without decreasing the trapping efficiency. Application of ExpoNano in a biomonitoring study revealed a total of 63 environmental chemicals detected in >50% of the urine pools collected from Chinese adults living in 13 cities, with a median concentration of 0.026-47 ng/mL, while nontargeted analysis detected an additional 243 exogenous molecules. Targeted and nontargeted analysis also detected 926 endogenous molecules in pooled urine. Collectively, the ExpoNano strategy demonstrates unique advantages over traditional urine analysis approaches, including a wide range of analytes, satisfactory trapping efficiency, high simplicity and reusability, and extremely reduced time demand and financial cost.

Preparation of mixed-mode weak cation exchange magnetic solid-phase extraction sorbent and its application in the extraction of 21 illicit drugs from wastewater

The detection of illicit drugs in wastewater can effectively monitor and evaluate the trend of illicit drug abuse. A novel mixed-mode cation exchange magnetic sorbent Fe3O4 @poly(ST/DVB/MA-COOH) was prepared and firstly applied as magnetically dispersed solid phase extraction material to efficiently, rapidly, and selectively extract 21 illicit drugs from wastewater. The selectivity of the sorbent was mainly attributed to the electrostatic interaction. The effects of Fe3O4 @poly(ST/DVB/MA-COOH) preparation and extraction conditions on the adsorption performance were thoroughly discussed. Among the 21 illicit drugs, the absolute extraction recovery values for 19 illicit drugs were greater than 80 % and the entire adsorption process could be achieved in one minute. Subsequently, the Fe3O4 @poly(ST/DVB/MA-COOH) sorbent combined with UHPLC-MS/MS was used to establish a quantitative method for the effectively extracted 19 illicit drugs in wastewater. The method had a good determination coefficient in the range of 0.2-200 ng/L and the limits of detection of the method were 0.03-0.67 ng/L. The spiked recovery values were in the range of 87.0-119.6 %. Finally, the method was successfully applied to the detection of 19 illicit drugs in wastewater samples and also compared with the commonly used SPE method. The obtained results indicate that Fe3O4 @poly(ST/DVB/MA-COOH) has great advantages in the detection of illicit drugs in wastewater.

Preparation of amino-functionalized triazine-based hyper-crosslinked polymer for efficient adsorption of endocrine disruptors

Herein, two novel amino-functionalized triazine-based hyper-crosslinked porous polymer (NH2-HCPs) (named as DPT-BB, DPT-DX) were designed and synthesized by direct crosslinking of 2,4-diamino-6-phenyl-1,3,5-triazine (DPT) with 4,4'-bis(chloromethyl)-1,1'-biphenyl (BB) or α, α'-dichloro-p-xylene (DX). Thanks to the amino functional group and hyper-crosslinked porous structure, NH2-HCPs displayed remarkable adsorption ability for phenolic EDCs. The adsorption mechanism mainly involved hydrogen bond, π-π interaction, hydrophobic interaction and pore filling. Thus DPT-BB was applied as solid phase extraction sorbent to extract phenolic EDCs from water and orange juice samples prior to quantitative analysis by high performance liquid chromatography. Under the optimal conditions, detection limit as low as 0.07-0.2 ng mL-1 for water and 0.1-0.27 ng mL-1 for orange juice was achieved. Good recoveries spanned the range of 83.5%-114% were obtained for spiked samples, with relative standard deviations below 8.9%. The results demonstrated that the developed method displayed excellent practicability for sensitive analysis of EDCs.

Adsorption of Pb2+ and Cu2+ in wastewater by lignosulfonate adsorbent prepared from corn straw

The heavy metal ions contained in industrial wastewater are a great threat to human health. Exploring a adsorbent which have low-cost, green environmental friendly, high adsorption capacity, good recycle is key to solve heavy metal ions pollution. Lignin sulfonate was obtained by treating corn stover, and then modified lignin sulfonate was obtained by hydrothermal method. The porous structure makes heavy metal ions occupy more internal adsorption sites. Modified lignosulfonate adsorbent efficiency removes heavy metals in wastewater especially Cu2+ and Pb2+. The adsorption capacity of Cu2+ on modified lignosulfonate is 450.3 mg g-1, Pb2+ is 475.4 mg g-1. In addition, for 40 mg L-1 Cu2+ and Pb2+ using 0.4 g L-1, the adsorption equilibrium is only reached within 60 min. Meanwhile, the removal ratio of Pb is 83 %, Cd is 72 %, Cu is 87 %, Zn is 36 %, Mn is 25 %, Cr is 95 %, and Fe is 99 % in wastewater using 0.4 g L-1 adsorbent in 2 h. This research develops a practical adsorbent to remove heavy metals from actual wastewater.

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.

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.

Solid-phase extraction and fractionation of multiclass pollutants from wastewater followed by liquid chromatography tandem-mass spectrometry analysis

Herein, we describe a modular solid-phase extraction (SPE) setup, combining three sorbents, for the effective extraction of neutrals, acidic, and basic micropollutants from wastewater, followed by their further elution in three independent extracts. The performance of this approach was demonstrated for a suite of 64 compounds, corresponding to different chemical families, using liquid chromatography tandem-mass spectrometry (LC–MS/MS). Target compounds were effectively extracted from wastewater samples; moreover, 62 out of 64 species were isolated in just one of the three fractions (neutrals, acids, and bases) obtained from the combination of sorbents. Globally, the efficiency and the selectivity of the SPE methodology improved the features obtained using generic SPE polymers, displaying just reversed-phase interactions. The overall recoveries of the analytical method, calculated against solvent-based calibration standards, stayed between 80 and 120% for 57 and 60 compounds, in raw and treated wastewater, respectively. Procedural limits of quantification (LOQs) varied from 1 to 20 ng L⁻¹. Analysis of urban wastewater samples identified a group of 19 pollutants showing either negligible median removal efficiencies (± 20%) during wastewater treatment, or even a noticeable enhancement (case of the biodegradation product of the drug valsartan), which might be useful as markers of wastewater discharges in the aquatic environment.

Occurrence, detection and ecotoxicity studies of selected pharmaceuticals in aqueous ecosystems- a systematic appraisal

Pharmaceutical compounds (PCs) have globally emerged as a significant group of environmental contaminants due to the constant detection of their residues in the environment. The main scope of this review is to fill the void of information on the knowledge on the African occurrence of selected PCs in environmental matrices in comparison with those outside Africa and their respective toxic actions on both aquatic and non-aquatic biota through ecotoxicity bioassays. To achieve this objective, the study focused on commonly used and detected pharmaceutical drugs (residues). Based on the conducted literature survey, Africa has the highest levels of ciprofloxacin, sulfamethoxazole, lamivudine, acetaminophen, and diclofenac while Europe has the lowest of all these PC residues in her physical environments. For ecotoxicity bioassays, the few data available are mostly on individual groups of pharmaceuticals whereas there is sparsely available data on their combined forms.

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.

First evaluation of genotoxicity of strong bases and zwitterions in treated household effluents

Various genotoxic substances in household effluents have not been sufficiently studied. The purpose of this study is to evaluate them using the umu test after dividing them based on the acid-base properties of their functional groups by solid-phase extraction cartridges. The results of the samples concentrated with reverse-phase cartridges showed that the substances with acid functional groups had stronger genotoxicity as 4.1-12.1 ng-4-NQO/mL without S9 enzyme and 17.4-51.8 ng-2-AA/mL with S9 enzyme, while the basic substances also showed a certain degree of toxicity. The results of dividing the effluents by acid-base properties using ion-exchange cartridges showed that chemical substances with strong acid functional groups did not demonstrate genotoxicity. It was found that the genotoxicity of chemicals with functional groups of weak acids was half of that of the total amount. The genotoxicity of the neutral substance was not strong, and the genotoxicity of the weak basic substances was negligible. The zwitterions and substances with strong basic functional groups showed about half the total genotoxicity. This is the first report that has investigated the genotoxicity of zwitterions in effluents.

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.

Skin bacteria of rainbow trout antagonistic to the fish pathogen Flavobacterium psychrophilum

Rainbow trout fry syndrome (RTFS) and bacterial coldwater disease (BCWD) is a globally distributed freshwater fish disease caused by Flavobacterium psychrophilum. In spite of its importance, an effective vaccine is not still available. Manipulation of the microbiome of skin, which is a primary infection gate for pathogens, could be a novel countermeasure. For example, increasing the abundance of specific antagonistic bacteria against pathogens in fish skin might be effective to prevent fish disease. Here, we combined cultivation with 16S rRNA gene amplicon sequencing to obtain insight into the skin microbiome of the rainbow trout (Oncorhynchus mykiss) and searched for skin bacteria antagonistic to F. psychrophilum. By using multiple culture media, we obtained 174 isolates spanning 18 genera. Among them, Bosea sp. OX14 and Flavobacterium sp. GL7 respectively inhibited the growth of F. psychrophilum KU190628-78 and NCIMB 1947^T, and produced antagonistic compounds of < 3 kDa in size. Sequences related to our isolates comprised 4.95% of skin microbial communities, and those related to strains OX14 and GL7 respectively comprised 1.60% and 0.17% of the skin microbiome. Comparisons with previously published microbiome data detected sequences related to strains OX14 and GL7 in skin of other rainbow trout and Atlantic salmon.

Facile synthesis of magnetic sulfonated covalent organic framework composites for simultaneous dispersive solid-phase extraction and determination of β-agonists and fluoroquinolones in food samples

In this work, an efficient method for the determination of β-agonists and fluoroquinolones was established, based on a mixed-mode sorbent of magnetic sulfonated covalent organic framework composites. By coupling with HPLC-MS/MS, the main factors that affect the extraction procedure were optimized. Under the optimal conditions, the proposed HPLC-MS/MS method was successfully utilized for the extraction of β-agonists and fluoroquinolones in milk and pork meat samples. The method showed good linearities (R² ≥ 0.9916), and low LOQs of 0.1-0.2 ng g^-1 for β-agonists and fluoroquinolones. The adsorption mechanism was investigated with the assistance of quantum chemistry calculation method, and it is worth noting that the sorbent relied mainly on the multiple adsorption mechanisms, including π-π stacking, hydrophobic, electrostatic attraction and hydrogen-bonding interactions. This work not only provides a simple method for the preparation of a mixed-mode sorbent, but also a routine analysis strategy for monitoring the illegal use of β-agonists and fluoroquinolones.

Enantiomeric determination of cathinones in environmental water samples by liquid chromatography-high resolution mass spectrometry

The enantiomeric determination of chiral drugs in the environment is of emerging concern since their enantiomers often exhibit stereoselectivity in environmental occurrence, fate and toxicity. In this study a method based on solid-phase extraction followed by chiral liquid chromatography and high-resolution mass spectrometry has been developed for the enantiomeric determination of a group of cathinones in river water and effluent wastewater. The enantioseparation was carried out using a Chiralpak CBH column in reversed-phase mode, and optimised by evaluating the effects of flow rate, buffer concentration and organic modifier. Under optimal conditions, good enantioseparations (R_s ≥1.2) were achieved for all the analytes. Two mixed-mode cation-exchange sorbents (Oasis WCX and Oasis MCX) in solid-phase extraction were evaluated in river water. Oasis MCX sorbent showed better performance with apparent recoveries ranging from 57 to 91% and matrix effect ranging from -10 to 15%. It is worth noting that a shifting of retention times and loss of enantioresolutions in environmental water samples was observed for all the analytes when the Oasis WCX sorbent was used. The method was validated with river water and effluent wastewater samples and its overall performance was satisfactory. The method quantification limits for all the analyte enantiomers ranged from 1.0 to 2.9 ng/L in river water, and from 2.3 to 6.0 ng/L in effluent wastewater. The repeatability and reproducibility values, expressed as% relative standard deviation (n = 5) were less than 15%. The method was then applied to the analysis of river water and effluent wastewater. The racemic methylone and methedrone (EF=0.49 and 0.46, respectively) were detected at low ng/L in some of the river water samples.