Solid-phase Microextraction Method Research Articles

Development of Magnetic Solid Phase Micro-Extraction (MSPE) Method for the Extraction and Preconcentration of the Selected β-Blockers in the Environmental Wastewaters

AbstractEmerging organic pollutants s have always been the greatest environmental concern due to their ubiquity and distinguished adverse effects. These are mostly water-bone pollutants flagged as endocrine disruptors and can greatly inconvenience the ecosystem. Among others, β-blockers have also been detected in the environment at various concentrations that threaten the well-being of humans and animals. In this work, NH2-MIL-101(Cr) doped magnetic nanoparticles nanocomposite was successfully synthesised and characterised using analytical techniques such as X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) and transmission electron microscopy (TEM). The Fe3O4@NH2-MIL-101(Cr) was then used as an adsorbent to extract the selected β-blockers in the environmental wastewater. The selected β-blockers were quantified using a high-performance liquid chromatography-diode array detector (HPLC-DAD). Parameters affecting the extraction were screened and optimised using fractional factorial design (FFD) and central composite design (CCD), respectively. Under optimum conditions, the LODs were 0.057 and 0.065 µg L− 1, and LOQs were 0.19 and 0.22 µg L− 1 for acebutolol (ACE) and metoprolol (MET), respectively. The calibration curve exhibited the linearity range of 0.2–1200 µg L− 1 with correlation coefficients of 0.9987 and 0.9968 for ACE and MET, respectively. Repeatability studies demonstrated the %RSD of 0.63 and 0.74% for MET and ACE. At the same time, reproducibility studies displayed the %RSD of 1.057 and 1.178% for MET and ACE, respectively. Spike recovery experiments were carried out to assess the performance of MSPE in real samples, and over 88% of both analytes were recovered. This indicated that the MSPE method could enrich various organic pollutants from different environmental matrices.

In vivo profiling of phytocannabinoids in Cannabis spp. varieties via SPME-LC-MS analysis

BackgroundIn vivo solid-phase microextraction (SPME) is a minimally invasive, non-exhaustive sample-preparation technique that facilitates the direct isolation of low molecular weight compounds from biological matrices in living systems. This technique is especially useful for the analysis of phytocannabinoids (PCs) in plant material, both for forensic purposes and for monitoring the PC content in growing Cannabis spp. plants. In contrast to traditional extraction techniques, in vivo SPME enables continuous tracking of the changes in the level of PCs during plant growth without the need for plant material collection. In this study, in vivo SPME utilizing biocompatible C18 probes and liquid-chromatography coupled to quadrupole time-of flight mass spectrometry (LC-Q-TOF-MS) is proposed as a novel strategy for the extraction and analysis of the acidic forms of five PCs in growing medicinal cannabis plants. ResultsThe SPME method was optimized by testing various parameters, including the extraction phase (coating), extraction and desorption times, and the extraction temperature. The proposed method was validated with satisfactory analytical performance regarding linearity (10–3000 ng/mL), limits of quantification, and precision (relative standard deviations below 5.5 %). The proposed method was then successfully applied for the isolation of five acidic forms of PCs, which are main components of growing medicinal cannabis plants. As a proof-of-concept, SPME probes were statically inserted into the inflorescences of two varieties of Cannabis spp. plants (i.e., CBD-dominant and Δ9-THC-dominant) cultivated under controlled conditions for 30 min extraction of tetrahydrocannabinolic acid (Δ9-THCA), cannabidiolic acid (CBDA), cannabigerolic acid (CBGA), cannabiviarinic acid (CBVA), and tetrahydrocannabivarinic acid (THCVA). Significance and noveltyThe results confirmed that the developed SPME-LC-Q-TOF-MS method is a precise and efficient tool that enables direct and rapid isolation and analysis of PCs under in vivo conditions. The proposed methodology is highly appealing option for monitoring the metabolic pathways and compositions of multiple PCs in medicinal cannabis at different stages of plant growth.

A zirconium metal–organic framework functionalized with a S/N containing carboxylic acid (MOF-808(Zr)-Tz) as an efficient sorbent for the ultrafast and selective dispersive solid phase micro extraction of chromium, silver, and rhodium in water samples

Metal-organic frameworks (MOFs) are good adsorbents for targeted chemicals with their adjustable properties. Herein, we prepared a zirconium based MOF (MOF-808(Zr)) and functionalized it employing 2-mercapto-4-methyl-5-thiazolacetic acid (MOF-808(Zr)-Tz). The prepared MOFs were characterized by XRD, FTIR, SEM-EDX, TGA, N2 sorption, zeta potential measurements, and elemental analysis. The surface area of MOF-808(Zr)-Tz was 1348 m2/g. Dispersive solid-phase micro-extraction (D-SPµE) method based on MOF-808(Zr)-Tz was firstly developed and applied to the extraction of chromium, silver, and rhodium in waters. The determination of the analytes was done by FAAS. The optimal pH and eluent for analytes were 7.0 and 3 mL of 2 mol L−1 HCl, respectively. The contact times were 1 min for adsorption and 3 min for elution. The LOD and PFs of the D-SPμE for analytes were 2.3 μg L−1 and 13.3 for chromium, 2.1 μg L−1 and 13.3 for silver, and 3.1 μg L−1 and 13.3 rhodium, respectively. The D-SPμE method was verified with analyses of NW-TMDA-54.6 Lake water and SPS-WW1 Batch 114 Wastewater and with spiked dam water, river water, well water, sea water, and wastewater. The recoveries of the analytes changed from 89 to 108 %. The results indicated that the method is selective, simple, effective, and rapid for extracting chromium(III), silver(I) and rhodium(III) in waters.

Development of a dispersive micro-solid phase extraction method based on using cobalamin as a green adsorbent for the extraction of Cd(II) and Pb(II) from oil samples

ABSTRACT A dispersive micro-solid phase extraction procedure using cobalamin as a green sorbent has been developed for the extraction of Cd(II) and Pb(II) ions from oil samples. At first, a desired amount of oil sample was dissolved in chloroform. Then, the specified amount of cobalamin was added and vortexed. After centrifuging, the separated solid particles were dissolved in nitric acid solution. Finally, the analytes were analysed by flame atomic absorption spectrometry. Effects of different analytical parameters such as amounts of sample and cobalamin, vortex time, complexing agent amount, type and volume of dissolving solvent, and temperature on the extraction efficiency of Pb(II) and Cd(II) ions were investigated and optimised. Under optimised conditions, calibration curves were established with the linear ranges of 1.5–150 μg Kg−1 for Cd(II) and 1–150 μg Kg−1 for Pb(II). The detection limits were found to be 0.48 and 0.34 µg Kg−1 along with extraction recoveries of 89.1% and 94.8% for Cd(II) and Pb(II) ions, respectively. The proposed method demonstrated good repeatability, with the relative standard deviation ranging from 3.8% to 4.1% (n = 6, C = 10 μg Kg−1 of each cation). Finally, the method was successfully applied to determine the concentrations of Cd(II) and Pb(II) ions in various oil samples.

Influence of the Different Maturation Conditions of Cocoa Beans on the Chemical Profile of Craft Chocolates.

Cocoa beans (Theobroma cacao L.) can be used for craft chocolate production, which arouses consumer interest due to their perceived better quality. This study aimed to evaluate the chemical profile of 80% artisanal chocolate samples produced with cocoa beans subjected to different maturation conditions. In the first maturation process, beans were matured under no-oxygen conditions, and in the second, the toasted beans were matured in oak barrels. The volatile compounds of the chocolate samples were extracted by the solid-phase microextraction method in headspace mode and analyzed by gas chromatography/mass spectrometer. The non-volatile compounds were extracted with methanol and analyzed through paper spray mass spectrometry. Overall, 35 volatile compounds belonging to different chemical classes (acids, alcohols, aldehydes, ketones, esters, and pyrazines) were identified, such as propanoic acid and butane-2,3-diol. In addition, 37 non-volatile compounds, such as procyanidin A pentoside and soyasaponin B, were listed. Tannins, flavonoids, and phenylpropanoids were the main chemical classes observed, varying between the two samples analyzed. Therefore, it was possible to verify that maturation conditions affected the metabolomic profile of the 80% artisanal chocolate samples, being able to influence the sensory characteristics and bioactive compounds profile. Given these results, the sensory evaluation of these chocolates is suggested as the next step.

A three-dimensional hierarchical porous graphene aerogel as a fiber coating for headspace solid-phase microextraction: Enhancing the enrichment and detection of polychlorinated naphthalenes in fish

In this study, a novel three-dimensional hierarchical porous deep eutectic solvents-modified graphene aerogel (3D DES-GA) was synthesized for use as a solid-phase microextraction (SPME) fiber coating. The SPME fiber was characterized by its fluffy and hierarchical porous structure, uniform thickness, and rapid mass transfer capabilities. This fiber demonstrated a lifetime (≥160 uses) and excellent precision (with relative standard deviations of 2.4–6.6% for single fiber and 6.0–9.8% for fiber-to-fiber repeatability). The SPME fiber also exhibited remarkable extraction performance for polycyclic aromatic hydrocarbons and polychlorinated biphenyls, which are common persistent organic pollutants in environmental samples. When combined with gas chromatography-tandem mass spectrometry, the method allowed for high-efficiency extraction (enrichment factors ranging from 1225 to 4652 folds) and sensitive determination (limit of detection ranging from 0.010 to 0.056 pg g−1) of polychlorinated naphthalenes (PCNs) in complex samples. To validate this method, we applied it to the determination of four PCNs in five types of fish tissues. The results revealed the presence of 1-chloronaphthalene at concentrations of 7.0 ± 2.9–34.8 ± 2.1 pg g−1 and 1,4-dichloronaphthalene at concentrations of 6.0 ± 0.3–10.9 ± 1.4 pg g−1 in three fish species. Compared with reported sample pretreatment methods reported in the literature, this proposed headspace SPME method offers additional advantages, including simplicity of operation and reduced sample and organic solvent consumption.

A MWCNTs@CuAl2O4@SiO2 Nanocomposite for the Speciation of Cr(III), Cr(VI), and Total Chromium Prior to High-Resolution Continuum Source Flame Atomic Absorption Spectrometric Determination

A solid-phase microextraction (SPME) method had been applied to speciate chromium in natural and wastewater samples. MWCNTs@CuAl2O4@SiO2 nanocomposite was synthesized by sol–gel and calcination methods and then characterized using SEM, FTIR, and XRD techniques. MWCNTs@CuAl2O4@SiO2 was used to extract Cr(VI) as pyrrolidine dithiocarbamate chelates. Some analytical parameters involving pH, ligand (APDC) and adsorbent amounts, sample initial and final volume, and the effects of matrices were tested and optimized. For the oxidation of Cr(III) to Cr(VI), potassium permanganate was used, and after that, the presented method was applied to determine the total chromium levels. The calculations were carried out to obtain Cr(III) concentration by finding differences between total chromium and Cr(VI) concentrations. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 6.2 µg L−1 and 20.8 µg L−1, respectively. The proposed method was successfully applied for chromium speciation in wastewater samples.

Development of Dry-herb vaporizer-assisted solid-phase Microextraction for the analysis of volatile Organic compounds

Solid-phase microextraction (SPME) is a simple, efficient, and solvent-free technique. It integrates the steps of traditional liquid-liquid extraction, i.e., sampling, extraction, concentration, derivatization, in a single step. It is easy, combining capability with gas chromatography (GC), liquid chromatography (LC), and mass spectrometry (MS), which makes this method fast, reliable, and sensitive. SPME method is often associated with extraction at elevated temperature, since increasing temperature may positively affect extraction by increasing the analyte volatility, diffusion, and extraction rate. In this work, a dry-herb vaporizer (vaping pen) was used as a sample heating device for direct desorption of volatile analytes into the headspace of the device. The extraction was performed by sorbing analytes from their gas phase in the headspace of the vape onto a SPME fiber followed by desorption in the injection port for GC–MS characterization. Compounds from horseradish, cinnamon, and gasoline-spiked soil samples were analyzed. The samples were also analyzed by conventional headspace SPME-GC–MS. The results from both methods were compared. The methods produce comparable results in terms of extracted compounds and relative area percentages, however, the dry-herb vaporizer had improved sensitivity.

A functionalized glass fiber as the adsorbent for efficient analysis of endocrine disruptors in aqueous environments

Estrogens and bisphenols are typical endocrine disruptors (EDs) that pose a potential hazard to the human body due to their widespread presence in aqueous environments. In this study, a β-cyclodextrin porous crosslinked polymer (β-CD-PCP) was prepared in-situ on a glass fiber surface by a nucleophilic substitution reaction. An effective and sensitive solid phase microextraction method using functionalized glass fiber with β-CD-PCP coating as the adsorbent was established for the detection of 11 EDs in a water environment. The β-CD-PCP was in-situ prepared on a glass fiber surface by a nucleophilic substitution reaction. The β-CD-PCP successfully separated five estrogens (ESTs) and six bisphenols (BPs) through hydrophobic and π-π interactions. The conditions affecting extraction were optimized. Under the optimized conditions, the ESTs obtained a high enrichment effect (1795–2328), low limits of detection (0.047 µg L−1) and a good linearity range (0.2–15.0 µg L−1). Furthermore, the spiked recoveries of analyte ESTs in aqueous environments were between 82.9–115.7 %. The results indicated that the prepared functionalized glass fibers exhibited good adsorption properties, and the established analytical method was reliable for monitoring trace ESTs and BPs in aqueous environments.

Determination of chromium in foodstuffs by using novel adsorbent in vortex assisted-dispersive solid phase micro-extraction method: An application of multivariate techniques

A new graft copolymer composed of polystyrene and polylinoleic acid (PLinas) with the sodium salt of iminodiacetate (Ida) was synthesized and used as an adsorbent. The vortex-assisted dispersive solid-phase micro-extraction (VA-dSPµE) method was used for the extraction and pre-concentration of chromium. Multivariate methodologies, such as factorial design and 3D surface plots, were applied for screening and optimizing effective extraction parameters. The influence of diverse analytical parameters, such as pH, sample volume, and interfering ions, on the extraction of chromium was studied. The calibration standard curve exhibited a linear range from 0.01 to 0.50 μg L−1. The relative standard deviation and limit of detection were found to be 1.65 % and 0.003 μg L−1, respectively. Extraction recoveries were found in the range of 96 to 99 % by using certified reference materials (CRMs). The adsorbent capacity of PLinas-Ida was found to be 112 mg g−1. The VA-dSPµE method demonstrated its effectiveness in the pre-concentration and determination of chromium within samples of foodstuffs by graphite furnace-atomic absorption spectrometry (GF-AAS).

Solid phase microextraction of rhodamine B in cosmetic samples using ZnS@GO@WMCNTs Nanocomposite with Spectrophotometric Detection

Rhodamine B dye (RhB) has carcinogenicity, genotoxicity, neurotoxicity and toxicity on living cells and therefore its use is prohibited. but it is still secretly used in cosmetics and foods. For this reason, it is important to develop analytical methods for accurate and sensitive analysis of trace levels of RhB dye in cosmetic and food samples. In this study, a new solid phase microextraction method (SPME) was developed for quick and cheap analysis of RhB in cosmetic samples. A new nanohybrid material including graphene oxide (GO), multi-walled carbon nanotubes (MWCNTs) and zinc sulfide nanopartices (ZnS) was synthesized by hydrothermal synthesis method and the new ZnS@GO@WMCNTs nanohybrid material was used as sorbent in simultaneous separation and preconcentration of RhB from cosmetic products by SPME. ZnS@GO@WMCNTs material was characterized by Raman spectroscopy, scanning electron microscopy (SEM), SEM-Mapping and energy dispersive X-Ray fluorescence (EDX) techniques. The effects of experimental parameters such as amount of sorbent, pH of sample solution, sample volume, effects of matrix, eluent solutions on the recoveries of RhB were investigated. RhB dye adsorbed on ZnS@GO@WMCNTs was eluted with acetic acid–ethanol mixture (2:1) and determined by using UV–Visible spectrophotometer at 550 nm. The fact that RhB adsorbed quantitatively on the adsorbent at all pH values shows that strong Van der Waals interactions between the ZnS@GO@WMCNTs and RhB molecules are effective in adsorption. In optimal experimental conditions, the limit of detection (LOD) and preconcentration factor (PF) of the proposed MSPE-UV/Vis spectroscopy procedure were 4.74 and 44, respectively. The MSPE-UV/Vis procedure was successfully applied to the microextraction and determination of RhB in nail polishs ve lipstick samples with recoveries in the range 95–101 %.

Application of Covalent Organic Framework-Based Solid-Phase Microextraction for Efficient and Direct Analysis of Neurotransmitters in the Striatum of Nicotine-Addicted mice

This study developed and validated a novel solid-phase microextraction (SPME) method based on covalent organic framework (COF) for the simultaneous analysis of 10 neurotransmitters (NTs) in mice brain tissue using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The synthesized COF was utilized as SPME fiber coating, exhibited a suitable pore size and macromolecule exclusion capability, ensuring excellent thermal stability and high adsorption efficiency for NTs. This allowed direct extraction from brain homogenates, eliminating the need for protein precipitation. And the COF-based SPME fiber exhibited good reusability throughout eight successive recycling cycles. The SPME-UHPLC method demonstrated excellent linearity (correlation coefficients > 0.99), low intra- and inter-day precision (RSDs ≤ 9.5 % and ≤ 10.6 %, respectively), and acceptable matrix effects (ranging 84.3 % to 117.3 %). The developed method was then applied to analyze NTs in the striatum of nicotine-addicted mice, and the statistical analysis revealed significant shifts in the concentrations of dopaminergic, serotonergic, glutamatergic, addiction and deepened the understanding of addiction's neurobiology. This method offers a sensitive and efficient approach for extracting polar NT analytes in complex matrices, profiling NT alterations linked to addiction, and holds potential for early detection and treatment of addiction disorders. It could contribute significantly to addiction neurobiology and neurological disease research.

Solid phase microextraction arrow-ion mobility spectrometry for determination of selected pesticides in water

Ion mobility spectrometry with corona discharge ion source was used for the measurements of selected pesticides cybutryne, terbutryn, dichlorvos, and quinoxyfen in water. The analyses were carried out by (i) direct injection of the aqueous solution of the pesticides and (ii) extraction using solid phase microextraction by commercial SPME arrows. The instrumental and the experimental extraction parameters including the drift tube temperature, injection port temperature, and the SPME fiber type were studied and optimized to achieve the maximum signal intensity. The limit of detections obtained by the direct injection were about 0.1–1.0 mg L−1. Using the SPME arrow-ion mobility spectrometry method, the detection limits were improved 7–50 times and obtained as 0.01, 0.015, 0.05, and 0.1 mg L−1 for terbutryn, dichlorvos, cybutryne, and quinoxyfen, respectively. The recovery rate for analysis in surface water (real samples) was approximately 90–110% for both the direct injection and solid phase microextraction method. The capability of ion mobility spectrometry for the simultaneous detection of a mixture of the studied pesticides was assessed, and it was found that terbutryn, dichlorvos, and quinoxyfen can be detected simultaneously without peak overlapping.

Synthesis and characterization of MoS2–COOH/gly/Mn nanocomposite as an efficient adsorbent for Ultra-trace determination of trifluralin herbicide

The world is confronting a severe water crisis. To clean up water from heavy metals, microorganisms, chemicals, and other types of pollutants, nanocomposites have been receiving great attention specifically due to the high surface area affording to work effectually even at low concentrations. In this research, we synthesized a new amino acid-modified MoS2 nanocomposite by chemically immobilizing Mn (II). The synthesized absorbent MoS2–COOH/gly/Mn was identified by thermogravimetric analysis (TGA), nitrogen adsorption measurement, X-ray diffraction (XRD), analysis of energy dispersive X-ray mapping (EDAX and MAP), field emission scanning electron microscopy (FE-SEM), and Fourier Transform Infrared spectrometry (FT-IR). The nanocomposite was employed as an adsorbent through the solid phase microextraction (SPME) method while trifluralin herbicide was chosen as a model compound. For the monitoring of trifluralin molecules, we employed an ion mobility spectrometry apparatus featuring a corona discharge ionization source. The SPME method's effectiveness was examined by investigating the stirring rate and extraction time as two crucial parameters, aiming to achieve trace analysis of trifluralin. Under the optimized condition of the trifluralin extraction, the coefficient (R2) and linear dynamic range (LDR) correlation were obtained at 0.9961 and 0.5–10 μg L−1, respectively. Relative recovery values the described approach were obtained in the span of 96–97% for agricultural wastewater samples. The quantification (LOQ) and limit of detection (LOD) were calculated at 0.5 and 0.15 μg L−1, respectively. The proposed nanocomposite absorbent has the capability to be applied as an efficient material for the extraction of trifluralin herbicide from different solutions.

Functionalized nanodiamonds with NiCoFe layered double hydroxides used as a novel adsorbent in dispersive solid phase microextraction for Pb(II) determination in juice samples

A new solid phase microextraction (SPME) method utilizing nanodiamonds@NiCoFe-LDH for the pretreatment and extraction of Pb(II) before sample determination through FAAS was developed. NiCoFe-LDH was synthesized by using a hydrothermal synthesis technique and then combined with functionalized nanodiamonds. For the characterization of nanodiamonds@NiCoFe-LDH composite, FT-IR, FE-SEM, and XRD were utilized. The analytical parameters (pH level, amount of sorbent, concentration of eluent, volumes of sample and eluent, desorption time), i.e., pH = 8.0, 5.0 mg, 0.5 mol/L, 50 mL, 1.5 mL, and 0.5 min, respectively, were studied to set the maximum efficiency of the developed method. Additionally, matrix effects were taken into consideration during the evaluation process using the standard addition method. The limit of detection (LOD) and the preconcentration factor (PF) were obtained as 0.62 ng mL-1 and 25, respectively. To confirm the accuracy of the newly developed method, certified reference materials (CRMs) (NIST SRM 1515 apple leaves and BCR-505 estuarine water) were employed. %RSD was calculated as 2.0–8.0. The optimized method was successfully implemented to quantify Pb(II) in commercially available fruit juices of various brands and flavors procured from local markets in Kayseri, Turkey. Compared to previously reported methods, the developed method demonstrated exceptional sensitivity, achieving a remarkably low LOD.

Facile fabrication of carbon nanotube hollow microspheres as a fiber coating for ultrasensitive solid-phase microextraction of phthalic acid esters in tea beverages.

The efficient extraction of phthalic acid esters (PAEs) is challenging due to their extremely low concentration, complicated matrices and hydrophilicity. Herein, hollow microspheres, as an ideal coating, possess significant potential for solid-phase microextraction (SPME) due to their fascinating properties. In this study, multiwalled carbon nanotube hollow microspheres (MWCNT-HMs) were utilized as a fiber coating for the SPME of PAEs from tea beverages. MWCNT-HMs were obtained by dissolving the polystyrene (PS) cores with organic solvents. Interestingly, MWCNT-HMs well maintain the morphology of the MWCNTs@PS precursors. The layer-by-layer (LBL) assembly of MWCNTs on PS microsphere templates was achieved through electrostatic interactions. Six PAEs, di-ethyl phthalate (DEP), di-iso-butyl phthalate (DIBP), di-n-butyl phthalate (DBP), benzyl butyl phthalate (BBP), di-2-ethylhexyl phthalate (DEHP) and di-n-octyl phthalate (DOP), were selected as target analytes for assessing the efficiency of the coating for SPME. The stirring rate, sample solution pH and extraction time were optimized by using the Box-Behnken design. Under optimal working conditions, the proposed MWCNT-HMs/SPME was coupled with gas chromatography-tandem mass spectrometry (GC-MS/MS) to achieve high enrichment factors (118-2137), wide linearity (0.0004-10 μg L-1), low limits of detection (0.00011-0.0026 μg L-1) and acceptable recovery (80.2-108.5%) for the detection of PAEs. Therefore, the MWCNT-HM coated fibers are promising alternatives in the SPME method for the sensitive detection of PAEs at trace levels in tea beverages.

Electrosynthesis of metal coordination cluster Zn5/polyaniline composite coating for headspace solid phase microextraction of nine volatile phenolic compounds in aqueous samples

A novel polyaniline (PANI) coating doped with Zn5(H2Ln)6(NO3)4 (Zn5, H3Ln=(1,2-bis(benzimidazole-2-yl)-ethenol) cluster on a stainless-steel wire was prepared by the electrodeposition method for the headspace solid-phase microextraction (HS-SPME) of nine volatile phenols. Scanning electron microscopy, Fourier transform infrared spectrometry, energy dispersive spectrometry and thermogravimetry were employed to characterize the morphology, composition, structure and thermal stability of the Zn5/PANI composite coating. The extraction efficiency of the Zn5/PANI composite coating for nine phenols was nearly 2 times higher than that of pure PANI coating. After the extraction conditions were optimized, an HS-SPME-gas chromatography-flame ionization detector (GC-FID) method was developed for the determination of nine phenols in water samples. The HS-SPME-GC-FID method had superior analytical performance with good linearities (0.05–50.0 μg/L) and low limits of detection (0.01–0.08 μg/L). Then, the proposed method was successfully applied for the determination of nine phenols in water samples with satisfactory recoveries (79.4–110.0%).

Insight into the interaction of tetrabromobisphenol A with sediment-derived dissolved organic carbon in a multiphase system by direct immersion solid phase microextraction

Tetrabromobisphenol A (TBBPA), a ubiquitously used commercial brominated flame retardant (BFR), has been widely detected in aquatic environments, and has aroused much attention due to its potential adverse effects on aquatic organisms. However, current research on the environmental fate and transport of TBBPA in the sediment–dissolved organic carbon (DOC)–water polyphase system is lacking. In this study, the sorption behavior of TBBPA in a water–DOC–sediment system was investigated using the direct-immersion solid-phase microextraction (DI-SPME) method, and the free dissolved concentration (Cw-SPME) and DOC adsorption concentration (CDOC) of TBBPA in water were measured by applying this DI-SPME approach. In addition, the effects of pH, ionic strength, and soluble organic concentration on the adsorption of TBBPA in the multiphase system were evaluated. The adsorption kinetics experimental results show that the adsorption behavior of TBBPA on sediments conforms to a linear model, suggesting that it could be mainly absorbed by sediments. The solid–water partition coefficient (Kd) of TBBPA was artificially reduced 1.54 times using the traditional liquid–liquid extraction method because the sorption behavior of the DOC was ignored, which could be accurately corrected using the DI-SPME method. The logKd and logKOC of TBBPA in the multiphase system were 4.12 ± 0.25 and 6.48 ± 0.25, respectively. Finally, the interference experiment revealed that the sorption behavior of TBBPA was affected by the pH, ionic strength (calcium ion), and humic acid concentration, apart from the lead ion concentration itself.

Volatile fingerprints of beef cooking methods using sol–gel‐based solid‐phase microextraction (SPME) and direct analysis in real‐time mass spectrometry (DART‐MS)

RationaleThe aroma profile of food is a complex mixture of volatile compounds that constitutes a major component of the overall eating experience. The food service industry and chefs therefore constantly seek ways to investigate and thereby enhance the aroma profile. Oven cooking, sous vide and pan fry are three cooking methods of beef commonly practised by chefs. Near real‐time analysis of volatile compounds from these three cooking methods will provide insight into respective volatile fingerprints and help improve cooking techniques.MethodsVolatile compounds from three beef cooking methods were captured using an in‐house sol–gel based solid phase microextraction (SPME) method and analysed using direct analysis in real‐time mass spectrometry (DART‐MS). A volatile organic compound (VOC) standard was used to demonstrate successful implementation of the sol–gel coating technique. Volatile features discriminating the three cooking methods were shortlisted and statistically assessed by univariate and multivariate analyses.ResultsThe VOC standard was successfully adsorbed by the sol–gel method and detected by DART‐MS. Hierarchical cluster analysis clearly demarcated three beef cooking methods based on their volatile fingerprints. Out of 65 significant features differentiating the cooking methods, 50 were at highest concentrations from pan‐fry cooking only, followed by 14 with highest concentrations from oven cooking followed by pan frying. Sous vide followed by pan frying showed lowest concentrations of almost all volatile features.ConclusionsThe sol–gel‐based solid‐phase microextraction technique combined with DART‐MS was successful in differentiating beef cooking methods based on their volatile fingerprints. A workflow for rapid assessment of the volatile profile from beef cooking methods was established, providing a baseline to further explore volatile profiles from other key ingredients.

Deep eutectic solvents for the determination of endocrine disrupting chemicals

The harmful effects of endocrine disrupting chemicals (EDCs) to humans and other organisms in the environment have been well established over the years, and more studies are ongoing to classify other chemicals that have the potential to alter or disrupt the regular function of the endocrine system. In addition to toxicological studies, analytical detection systems are progressively being improved to facilitate accurate determination of EDCs in biological, environmental and food samples. Recent microextraction methods have focused on the use of green chemicals that are safe for analytical applications, and present very low or no toxicity upon disposal. Deep eutectic solvents (DESs) have emerged as one of the viable alternatives to the conventional hazardous solvents, and their unique properties make them very useful in different applications. Notably, the use of renewable sources to prepare DESs leads to highly biodegradable products that mitigate negative ecological impacts. This review presents an overview of both organic and inorganic EDCs and their ramifications on human health. It also presents the fundamental principles of liquid phase and solid phase microextraction methods, and gives a comprehensive account of the use of DESs for the determination of EDCs in various samples.