Selective determination of 2-aminobenzothiazole in environmental water and organic extracts from fish and dust samples.

In the present study, a homemade mixed-mode ion-exchange sorbent based on silica with embedded graphene microparticles is applied for the selective extraction of 2-aminobenzothiazole (NHBT) followed by determination through liquid chromatography coupled to high-resolution mass spectrometry. The sorbent was evaluated for the solid-phase extraction of NHBT from environmental water samples (river, effluent wastewater, and influent wastewater), and NHBT was strongly retained through the selective cation-exchange interactions. Therefore, the inclusion of a clean-up step of 7 mL of methanol provided good selectivity for the extraction of NHBT.

Evaluation of ceramic passive samplers using a mixed-mode strong cation-exchange sorbent to monitor polar contaminants in river water.

Although most of the analytical methods developed for the monitoring of contaminants in environmental waters are based on discrete grab sampling, an alternative of increasing interest is the use of passive sampling. Methods based on passive sampling provide the sampling and pre-concentration of the analytes in-situ, which makes the sample treatment less time consuming and costly than using discrete grab sampling. In this study, ceramic passive samplers (CPSs) using mixed-mode strong cation-exchange sorbent (Oasis MCX) as retention phase were evaluated for the determination of a group of 21 therapeutic and illicit drugs and some of their metabolites in river water samples that were determined by liquid chromatography-tandem mass spectrometry.

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).

Multiresidue analytical method for high production volume chemicals in dust samples, occurrence and human exposure assessment.

A multiresidue analytical method based on pressurised liquid extraction and gas-chromatography mass spectrometry was developed to determine 22 compounds belonging to different chemical families in indoor dust.: Seven organophosphate esters, six phthalate esters, three benzotriazoles, five benzothiazoles and four benzenesulfonamides were included in the present study, all of them belonging to the category of high production volume chemicals (HPVCs). Apparent recoveries ranged between 45% and 123% and method quantification limits ranged from 0.

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.

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.

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.

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

Solid-phase extraction (SPE) is a widely-used and very well-established sample preparation technique for liquid samples. An area of on-going focus for innovation in this field concerns the development of new and improved SPE sorbents that can enhance the sensitivity and/or the selectivity of SPE processes. In this context, mixed-mode ion-exchange sorbents have been developed and commercialised, thereby allowing enhanced capacity and selectivity to be offered by one single material.

Selective monitoring of acidic and basic compounds in environmental water by capsule phase microextraction using sol-gel mixed-mode sorbents followed by liquid chromatography-mass spectrometry in tandem.

In addition to the diverse extraction techniques available, capsule phase microextraction (CPME), which uses a microextraction capsule (MEC), has recently been introduced as a sorptive-based sample preparation technique. In this study, two different MECs (MEC-C18/SAX and MEC-C18/SCX) based on mixed-mode ion-exchange technology were synthesized and evaluated for the selective extraction of a group of ionizable compounds, including acidic and basic analytes. A sulfonic acid was used as the cation-exchange group in MEC-C18/SCX, and a quaternary amine as the anion-exchange group in MEC-C18/SAX.

Overview of mixed-mode ion-exchange materials in the extraction of organic compounds.

Mixed-mode ion-exchange materials, including silica-based, polymer-based and other supports, have been applied in sample treatment with different techniques, mainly solid-phase extraction, but also other microextraction techniques such as solid-phase microextraction, stir bar sorptive extraction and microextraction by packed sorbent. These materials are widespread because they conveniently combine capacity (through the reversed-phase interactions in the material backbone) and selectivity (through the specific ion-exchange interactions). This review provides an overview of the advances and applications of mixed-mode ion-exchange materials for the extraction of organic compounds from complex matrices in environmental, food and biological samples.

Comparison of polysaccharide-based and protein-based chiral liquid chromatography columns for enantioseparation of drugs.

Two different columns-Lux Cellulose-1 and Chiralpak CBH-were evaluated for their chiral recognition abilities for eight drugs comprising three β-blockers, one antacid, and four cathinones in polar-organic elution mode and reversed-phase elution mode, respectively. The factors that affected the enantioseparation were tested and optimized to develop a suitable chiral separation method whose LC conditions are compatible with MS detection. In polar-organic elution mode with the Lux Cellulose-1 column, methanol and acetonitrile were tested as the main components of the mobile phase.

Mixed-mode ion-exchange polymeric sorbents in environmental analysis.

When determining contaminants from environmental samples, sample treatment plays an important role. Among the different extraction techniques available, solid-phase extraction (SPE) has been commonly used for liquid samples, as well as for solid samples after an extraction technique amenable for solids. The broad applicability of SPE is attributed to the availability of different sorbents.

Optimised extraction methods for the determination of trichothecenes in rat faeces followed by liquid chromatography-tandem mass spectrometry.

The mycotoxin deoxynivalenol (DON) and some of its derivatives, such as 3‑acetyl‑deoxynivalenol (3AcDON), 15‑acetyl‑deoxynivalenol (15AcDON), deoxynivalenol‑3‑glucoside (DON3G) and de-epoxy deoxynivalenol (DOM-1), are commonly found in food and/or biological samples. However, literature does not present suitable methodologies for detecting and quantifying these mycotoxins at very low levels, which would be especially useful when they are present in biological samples. The main goal of the present paper was to evaluate different extraction techniques for the determination of these mycotoxins in rat faecal samples, in order to reduce the interferences present in the matrix and be able to quantify the mycotoxins at low concentration levels.

Monitoring and evaluation of the interaction between deoxynivalenol and gut microbiota in Wistar rats by mass spectrometry-based metabolomics and next-generation sequencing.

Published evidence has demonstrated the several toxic characteristics of mycotoxins and their considerable risk to human and animal health. One of the most common uncertainties regards whether if very low concentrations of the mycotoxin deoxynivalenol (DON), easily consumed within the Mediterranean Diet, can cause metabolic alterations; some of them produced by the interaction between DON and gut microbiota. Accordingly, faecal samples were collected from Wistar rats that had consumed the mycotoxin DON at low levels (60 and 120 μg kg body weight of DON per day), and were analysed by ultra-high performance liquid chromatography coupled with tandem mass spectrometry detection, in order to monitor the mycotoxin DON and its metabolite de-epoxy deoxynivalenol (DOM-1).

Novel capsule phase microextraction in combination with liquid chromatography-tandem mass spectrometry for determining personal care products in environmental water.

A novel sample preparation technique named capsule phase microextraction (CPME) is presented here. The technique utilizes a miniaturized microextraction capsule (MEC) as the extraction medium. The MEC consists of two conjoined porous tubular polypropylene membranes, one of which encapsulates the sorbent through sol-gel technology, while the other encapsulates a magnetic metal rod.

Hypercrosslinked particles for the extraction of sweeteners using dispersive solid-phase extraction from environmental samples.

This work presents a new extraction material, namely, Q-100, based on hypercrosslinked magnetic particles, which was tested in dispersive solid-phase extraction for a group of sweeteners from environmental samples. The hypercrosslinked Q-100 magnetic particles had the advantage of suitable pore size distribution and high surface area, and showed good retention behavior toward sweeteners. Different dispersive solid-phase extraction parameters such as amount of magnetic particles or extraction time were optimized.

Combining cationic and anionic mixed-mode sorbents in a single cartridge to extract basic and acidic pharmaceuticals simultaneously from environmental waters.

The aim of the present study is to broaden the applications of mixed-mode ion-exchange solid-phase extraction sorbents to extract both basic and acidic compounds simultaneously by combining the sorbents in a single cartridge and developing a simplified extraction procedure. Four different cartridges containing negative and positive charges in the same configuration were evaluated and compared to extract a group of basic, neutral, and acidic pharmaceuticals selected as model compounds. After a thorough optimization of the extraction conditions, the four different cartridges showed to be capable of retaining basic and acidic pharmaceuticals simultaneously through ionic interactions, allowing the introduction of a washing step with 15 mL methanol to eliminate interferences retained by hydrophobic interactions.

Determination of seven drugs of abuse and their metabolites in surface and wastewater using solid-phase extraction coupled to liquid chromatography with high-resolution mass spectrometry.

A method based on liquid chromatography with electrospray ionization high-resolution mass spectrometry (Exactive Orbitrap) combined with solid-phase extraction using a strong cationic exchange mixed-mode sorbent has been developed for the determination of seven drugs of abuse, including two synthetic cathinones, as well as some of their metabolites in environmental water samples. The method provides low detection limits and a high confirmation power thanks to the diagnostic and two fragment ions monitored for each compound in high-resolution mass spectrometry, providing six identification points for each analyte. The clean-up step based on methanol in the extraction step adequately decreased the matrix effect, mainly for river and effluent water, and provided suitable process efficiency.

Determination of mycotoxins in plant-based beverages using QuEChERS and liquid chromatography-tandem mass spectrometry.

A method was developed for the simultaneous determination of 11 mycotoxins in plant-based beverage matrices, using a QuEChERS extraction followed by ultra-high performance liquid chromatography coupled to tandem mass spectrometry detection (UHPLC-(ESI)MS/MS). This multi-mycotoxin method was applied to analyse plant-based beverages such as soy, oat and rice. QuEChERS extraction was applied obtaining suitable extraction recoveries between 80 and 91%, and good repeatability and reproducibility values.

Pressurised liquid extraction and liquid chromatography-high resolution mass spectrometry to determine high-intensity sweeteners in fish samples.

An analytical method based on pressurised liquid extraction (PLE) followed by liquid chromatography-high resolution mass spectrometry (Orbitrap) was developed for the simultaneous determination of ten high-intensity sweeteners in fish samples. As the method was developed, the different PLE parameters were optimised and different clean-up strategies were evaluated, of which in-cell clean-up using alumina and on-cell clean-up with hexane were the most effective. PLE recoveries were between 43% and 94%.

Different sample treatments for the determination of ICM-XR in fish samples followed by LC-HRMS.

Iodinated X-ray contrast media (ICM-XR) are a group of pharmaceuticals widely used in medicine. Due to their low biodegradation rate, which makes their removal at wastewater treatment plants difficult, and the high doses at which they are administered, they have been detected in aquatic environments. In the present paper, a method for the quantitative determination of a group of ICM-XR in different fish species was developed and validated for the first time.

Dynamic fabric phase sorptive extraction for a group of pharmaceuticals and personal care products from environmental waters.

This paper describes for the first time the use of a new extraction technique, based on fabric phase sorptive extraction (FPSE). This new mode proposes the extraction of the analytes in dynamic mode in order to reduce the extraction time. Dynamic fabric phase sorptive extraction (DFPSE) followed by liquid chromatography-tandem mass spectrometry was evaluated for the extraction of a group of pharmaceuticals and personal care products (PPCPs) from environmental water samples.