RESUMEN

Nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) are pervasive contaminants in aquatic environments. They are characterized by persistence, toxicity, bioaccumulation, and long-range transport, significantly threatening human health. The development of sensitive methods for nitro-PAH analysis in environmental samples is in great need. This study developed a novel carbonaceous SPME coating derived from metal-organic framework (MOF), namely a spherical assembly consisting of carbon nanorods with hierarchical porosity (HP-MOF-C), for the extraction and determination of nitro-PAHs in waters. The HP-MOF-C coated fiber demonstrated superior nitro-PAH extraction efficiencies, with enrichment factors 2∼70 times higher than commercial fibers. This enhancement was due to the strong hydrophobic, π-π electron coupling/stacking, and π-π electron donor-acceptor interactions between the carbonaceous framework of HP-MOF-C and the nitro-PAHs. Moreover, the unique hierarchical porous structure of HP-MOF-C accelerated the diffusion of nitro-PAHs, further facilitating their enrichment. The fiber also exhibited good thermal stability, remarkable chemical stabilities against common acid, base, and polar/non-polar solvents, and long service life (> 150 SPME cycles). The nitro-PAH determination method based on HP-MOF-C coating yielded wide linear ranges, low detection limits (0.4∼5.0 ng L-1), satisfactory repeatability and reproducibility, and good recoveries in real water samples. The proposed method was considered to be green according to the Analytical GREEnness assessment. The present study not only offers an efficient SPME coating for the enrichment of nitro-PAHs, but also provides insights into the design of porous coating materials.

RESUMEN

Because of rapid industrialization and agriculturalization, solving the pressing problems of environment pollution, especially water and food quality, requires innovative solutions. In this paper, a novel and versatile metal-organic framework (ZIF-8)-hybrid monolithic column (ZIF-HMC) was prepared for in-tube solid-phase microextraction (IT-SPME) of organic nitrogen pesticides (ONPs). The prepared monolithic columns had superior adsorption sites, high porosity, excellent permeability, and ideal specific surface area based on Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Thermal Field Emission Scanning Electron Microscopy (SEM), Energy Dispersive Spectrometry (EDS), X-ray Photoelectron Spectroscopy (XPS), and N2 adsorption-desorption. The ZIF-HMC contained a large number of nitrogen and oxygen atoms, benzene rings and ZIF-8, which could synergistically promote the adsorption efficiency of ONPs through multiple interactions, such as hydrogen bonding, π-π accumulation, hydrophobic interactions, cation-π interactions, and pore adsorption by MOFs. Under the optimal conditions, a simple, efficient, and sensitive method for the analysis of six organic pesticides in environmental water samples was developed by using the ZIF-HMC as the extraction medium coupled with high performance liquid chromatography-ultraviolet (HPLC-UV). The method had a wide linear range (0.63-1000 µg L-1), a low detection limit (0.19-1.91 µg L-1) and satisfactory recoveries (87.4 %-110.2 %), the linear correlation coefficient was (R2) 0.9972-0.9995 and the relative standard deviation (RSD) was less than 2.64 %. The study had demonstrated the potential application of the developed method for the enrichment and analysis of organic pesticides in complex matrices of environmental samples, as well as the feasibility of MOFs materials for IT-SPME sample preparation.

RESUMEN

Assessment and control of emerging organic pollutants in food have become critical for global food safety and health. The European Union has set standards for certain emerging organic pollutants, such as phthalic acid esters (PAEs) in food. Because of being endocrine disruptors, PAEs are toxic and carcinogenic to humans. Release of PAEs from packaging materials poses a potential risk to human health and causes environmental pollution. In this study, a highly sensitive analytical method for the detection of PAE contents in tea beverages was established using hydroxyl-functionalized covalent organic frameworks (COFs) as solid-phase microextraction (SPME) coating. Results indicate that functionalization with hydroxyl groups enhances the adsorption of PAEs. The proposed method exhibits a wide linear range (1-20,000 ng L-1), low limits of detection (> 0.048 ng L-1), and satisfactory recovery (72.8 %-127.3 %). To investigate the PAE contamination in beverages, contamination levels of six typical PAEs and their health impacts were surveyed across various brands/types/packaging materials of tea beverages sold in China. Results of the hazard quotient and hazard index approaches suggest no or extremely low health concerns regarding PAE levels. We observe that hydroxyl groups functionalized on COFs enhance the adsorption of PAEs. Moreover, an important outcome of this study is development of an efficient and sensitive direct detection method for PAEs in complex tea matrices, providing a reliable approach for the assessment of PAEs in other complex matrices.

RESUMEN

MAIN CONCLUSION: New findings are presented for Chaerophyllum coloratum L. on the volatile composition of the essential oil, based on data of hydrosol and fresh plant material, light and electron microscopy of leaves, and cytotoxic and antiviral activity. The widespread Apiaceae family includes many well-known and economically important plants that are cultivated as food or spices. Many produce essential oils and are generally a source of secondary metabolites and compounds that have numerous applications in daily life. In this study, the chemical composition of volatile organic compounds (VOCs), ultrastructure and biological activity of the Mediterranean endemic species Cheaerophyllum coloratum L. are investigated, as literature data for this plant species are generally very scarce. The essential oil and hydrosol were extracted from the air-dried leaves by hydrodistillation and the chemical composition of both extracts was analysed by GC-MS in conjunction with headspace solid-phase microextraction (HS-SPME) of VOCs from the hydrosol and the fresh plant material. In the composition of the essential oil, the oxygenated sesquiterpenes spathulenol and caryophyllene oxide were the most abundant components. In the fresh plant material, non-oxygenated sesquiterpenes dominated, with ß-caryophyllene and germacrene D being the main components. The hydrosol was dominated by monoterpenes, with the oxygenated monoterpene p-cymen-8-ol being the most abundant. Light and electron micrographs of the leaf of C. coloratum show secretory structures, and we hypothesize that glandular leaf trichomes, secretory epidermal cells and secretory canals are involved in the production of volatiles and their secretion on the leaf surface. Since the biological potential of C. coloratum is poorly investigated, we tested its cytotoxic activity on cancer and healthy cell lines and its antiviral activity on plants infected with tobacco mosiac virus (TMV). Our results dealing with the composition, ultrastructure and biological activity show that C. coloratum represent a hidden valuable plant species with a potential for future research.

Asunto(s)

RESUMEN

Passive smoking from environmental tobacco smoke not only increases the risk of lung cancer and cardiovascular disease but may also be a stressor triggering neuropsychiatric and other disorders. To prevent these diseases, understanding the relationship between passive smoking and stress is vital. In this study, we developed a simple and sensitive method to simultaneously measure nicotine (Nic) and cotinine (Cot) as tobacco smoke exposure biomarkers, and cortisol (CRT), serotonin (5-HT), melatonin (MEL), dopamine (DA), and oxytocin (OXT) as stress-related biomarkers. These were extracted and concentrated from saliva by in-tube solid-phase microextraction (IT-SPME) using a Supel-Q PLOT capillary as the extraction device, then separated and detected within 6 min by liquid chromatography-tandem mass spectrometry (LC-MS/MS) using a Kinetex Biphenyl column (Phenomenex Inc., Torrance, CA, USA). Limits of detection (S/N = 3) for Nic, Cot, CRT, 5-HT, MEL, DA, and OXT were 0.22, 0.12, 0.78, 0.39, 0.45, 1.4, and 3.7 pg mL-1, respectively, with linearity of calibration curves in the range of 0.01-25 ng mL-1 using stable isotope-labeled internal standards. Intra- and inter-day reproducibilities were under 7.9% and 14.6% (n = 5) relative standard deviations, and compound recoveries in spiked saliva samples ranged from 82.1 to 106.6%. In thirty nonsmokers, Nic contents positively correlated with CRT contents (R2 = 0.5264, n = 30), while no significant correlation was found with other biomarkers. The standard deviation of intervals between normal beats as the standard measure of heart rate variability analysis negatively correlated with CRT contents (R2 = 0.5041, n = 30). After passive smoke exposure, Nic levels transiently increased, Cot and CRT levels rose over time, and 5-HT, DA, and OXT levels decreased. These results indicate tobacco smoke exposure acts as a stressor in nonsmokers.

Asunto(s)

RESUMEN

Detection of ignitable liquid residues in a fire scene is essential for determining the origin. Although studies are focused on the detection of residues of accelerants depending on time or matrices, the time-dependent effect of the water extinguishing method in a fire has not yet been investigated. Experimental studies are needed to determine how long ignitable liquid residues can be detected in water-extinguished evidence compared to the smothering method. In this study, the effects of both extinguishing methods on gasoline residues were investigated after burning of carpet, sofa fabric, tablecloth, and towel by Solid Phase Micro Extraction- Gas Chromatography/Mass Spectrometry (SPME-GC/MS) technique. Four mandatory and 14 additional compounds were considered to prove the gasoline residue after the monitoring of possible interferences. Results showed that gasoline residues on the burned carpet and sofa fabric samples were successfully detected in both extinguishing methods up to 60 and 30 days after fire exposure, respectively due to multi-layered structures of related substrates. Additionally, the prolonged detection time of the water-extinguishing method made it particularly beneficial for single-layered products like tablecloths, where gasoline residues were found after an hour in this substrate. This is the first study investigating the effects of the extinguishing methods depending on time for textile products, which are the most used materials in houses. In addition, the fact that acrylamide-containing sofa fabric was investigated for the first time and that gasoline residues in carpet samples can be detected up to 60 days makes this study stand out.

RESUMEN

The comprehensive determination of fatty acids without derivatization, including short-chain fatty acids (SCFAs), medium-chain fatty acids (MCFAs) and long-chain fatty acids (LCFAs), is a big challenge but powerful for lipidomics in biology, food, and environment. Herein, the dual mode unity solid-phase microextraction (DMU-SPME) combined with gas chromatography-flame ionization detector (GC-FID) or mass spectrometry (MS) was proposed as a powerful method for the determination of comprehensive free fatty acids in real samples. Under the optimized DMU-SPME conditions, the proposed method has good linearity (R2 ≥ 0.994) and low limits of determination (0.01-0.14 mg/L). In the stability analysis, the intra-day relative standard deviation was 1.39-12.43 %, and the inter-day relative standard deviation was 2.84-10.79 %. The recoveries of selected 10 fatty acids in real samples ranged from 90.18 % to 110.75 %, indicating that the method has good accuracy. Fatty acids ranging from C2 to C22 were detected in real samples by the untargeted determination method of DMU-SPME combined with gas chromatography-mass spectrometry (GC-MS). The DMU-SPME method proposed in this study can be used for lipid metabolism analysis and free fatty acid determination in the fields of biology, food, and environment.

Asunto(s)

RESUMEN

A sensitive and accurate analysis of organochlorine pesticide (OCP) residues in dairy products poses a significant challenge. Herein, a novel covalent organic polymer, Azo-COP-1, was synthesized for the enhanced extraction of OCPs in dairy products. The solid phase microextraction fiber coated with Azo-COP-1 demonstrated excellent extraction performance for the OCPs via hydrogen bonding, halogen bonding, π-π stacking, and electrostatic interactions. Coupled with gas chromatography-electron capture detection, we developed a facile and reliable method for detecting OCPs in six types of dairy products with low limits of detection (2.0-400 pg g-1) and high method recoveries (82.6-113%). Azo-COP-1 coatings exhibited good stability and durability. The results verified the feasibility of using Azo-COP-1-based SPME to extract OCP residues in dairy product samples, highlighting its potential for routine monitoring of pesticide residues and food safety assessments.

Asunto(s)

RESUMEN

A simple and quick fiber-in-tube solid-phase microextraction (FIT-SPME) was introduced for the extraction and determination of nine polycyclic aromatic hydrocarbons followed by a high-performance liquid chromatography-ultraviolet detector in refinery water samples. For this purpose, a water-resistant metal-organic framework with a high surface area called UiO-66 has been applied in the form of an electrospun coating on stainless steel wires. After that, all the fibers were packed in the lumen of a stainless-steel tube to make the extraction phase. Both one variable at a time and experimental design methods have been used to optimize effective parameters on FIT-SPME. Under optimum conditions, the method demonstrated good linearity between 0.5 and 1000.0 µg/L with a coefficient of determination greater than 0.9906. Furthermore, the limits of detection values ranged from 0.2 to 1.5 µg/L. The intra-day and inter-day relative standard deviations were < 8.4% and < 9.7%, respectively. Lastly, the proposed method was applied to extract and determine analytes in four refinery water samples as well as surface water containing high total dissolved solids, and well waters where satisfactory results have been obtained.

RESUMEN

Organophosphorus pesticides (OPPs) present in tea infusions pose a serious threat to human health. In this study, a sensitive method for the determination of OPPs was developed based on a direct-immersion solid-phase microextraction (DI-SPME) probe. By fine adjustment of the ratio and one-step polymerization of dihydroxy-functionalized zirconium-based metal-organic framework UiO-66-(OH)2 and divinylbenzene-N-vinyl pyrrolidone (DVB-NVP) microspheres, the DVB-NVP@ UiO-66-(OH)2 (D-N@U) composite with an optimal hydrophilic-lipophilic balance (HLB) was achieved. Furthermore, D-N@U was adhesively bonded to stainless-steel wires to fabricate a DI-SPME probe. OPPs, especially those with nonpolar properties characterized by a high octanol-water partition coefficient (log KOW), were selectively and efficiently enriched on the D-N@U-coated DI-SPME probe from tea infusions. Coupled with a gas chromatography-flame photometric detector, the as-fabricated D-N@U-coated DI-SPME probe achieved good performance for OPPs analysis with a wide linear dynamic range of 0.10-500.00 µg/L and low detection limits of 1.96-6.69 ng/L. Moreover, in spiked samples, the recoveries and relative standard deviations were in the ranges of 73.12%-101.20 % and 1.03%-6.56 %, respectively. Owing to its simple operation, high extraction efficiency, and high sensitivity, this approach has great potential for the rapid determination of multiple pesticide trace-level residues in food.

RESUMEN

A method for the determination of eight benzenes (BTEXs) and twelve chlorobenzenes (CBs) in goat's milk by headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS/MS) was developed. The study investigated the impact of various factors such as extraction fiber type, salt amount, equilibrium conditions, and desorption conditions on the outcomes. Target analytes were separated on a DB-HeavyWAX column and quantified using the external standard method. The results showed that the target compounds had a good linear relationship in the range of 0.01 ∼ 50 µg/L (R2 > 0.997), the limit of detection (LOD) was 0.003 ∼ 0.150 µg/L, and the limit of quantification (LOQ) was 0.01 ∼ 0.50 µg/L. The average recoveries were 82%-116% and the relative standard deviation (RSD) was 0.8%-17.3% under the three addition levels of 1×, 2×, and 10 × LOQ. In a survey of twenty goat's milk samples, only ethylbenzene, xylenes, cumene, chlorobenzene, and 1,4-dichlorobenzene were detected at levels exceeding their respective limits of quantification. The method was evaluated using two ecological scales (Eco-Scale), GAPI and AGREEN, to verify its environmental friendliness and applicability. This method is simple, green, and efficient, which provides a certain theoretical basis for the production and quality safety evaluation of dairy products.

RESUMEN

INTRODUCTION: Waste by-products of the juice industry appear valuable for the circular economy concept, considering that the peel accounts for almost half of the total fruit weight. Therefore, the recovery of these highly valuable components from relevant biowaste has become a very interesting research topic. OBJECTIVE: The current study aims to develop an extraction process integrated with hydrophobic deep eutectic solvent (DES) based on statistical experimental design approach. MATERIAL AND METHODS: Homogenizer-assissted extraction (HAE) was used to recover the citrus extract rich in limonene (the main component of the volatile mixture) from lemon peels. Menthol-based deep eutectic mixtures were accompanied by carboxylic acids (formic, acetic, and propionic acids). Optimization continued on the combination that gave the highest efficiency (in terms of limonene content) among the solvents prepared at different molar ratios (1/1, 1/2, and 2/1). Process parameters were analyzed to optimize the process through central composite design with response surface method (RSM). D-Limonene yield was quantified with gas chromatography-mass spectrometry (GC-MS) with solid-phase microextraction (SPME) technique. The quality of the lemon peel extracts was also evaluated with respect to in vitro bioactivity assays (phenolic content and 2,2-diphenyl-1-picrylhydrazyl [DPPH] free radical scavenging activity). RESULTS: The maximum yield (3.80 mg-limonene per g fresh sample) was achieved by 2 mg solid/30 mL DES, ~53 sec, and ~8500 rpm. Statistically most effective variable was identified as solid mass, followed by second powers of mixing speed and extraction time at p < 0.0001.

RESUMEN

The ubiquitous presence and persistence of per- and polyfluoroalkyl substances (PFAS) in the environment have raised concerns in the scientific community. Current research efforts are prioritizing effective PFAS remediation through novel sorbents with orthogonal interaction mechanisms. Recognized sorption mechanisms between PFAS and sorbents include hydrophobic, electrostatic, and fluorine-fluorine interaction. The interplay of these mechanisms contributes significantly to improved sorption capacity and selectivity in PFAS separations. In this study, a primary/secondary amine-functionalized polystyrene-divinylbenzene (Sepra-WAX) polymer was modified to create a fluorinated WAX resin (Sepra-WAX-KelF-PEI). The synthesis intermediate (Sepra-WAX-KelF) was also tested to assess the improvement of the final product (Sepra-WAX-KelF-PEI). The adsorption capacity of Sepra-WAX, Sepra-WAX-KelF, and Sepra-WAX-KelF-PEI, and their interactions with PFAS were evaluated. The effect of pH, ionic strength, and organic solvents on PFAS sorption in aqueous solution was also investigated. The sorbents showed varied adsorption capacities for perfluorooctanoic acid, perfluoropentanoic acid, perfluoro-n-decanoic acid, and hexafluoropropylene oxide dimer acid, with the average extraction capacity of the four analytes being Sepra-WAX-KelF-PEI (523 mg/g) > Sepra-WAX (353 mg/g) > Sepra-WAX-KelF (220 mg/g). Sepra-WAX-KelF-PEI provided the highest adsorption capacity for all analytes tested, proving that the combination of electrostatic and hydrophobic/fluorophilic interactions is crucial for the effective preconcentration of PFAS and its future applications for PFAS remediation from aqueous solutions.

RESUMEN

Fungi of the genus Ceratocystis are aggressive tree pathogens that cause serious diseases in several crops around the world. Ceratocystis wilt disease caused by C. cacaofunesta has been shown to be responsible for severe reductions in cacao production. In this study, headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) was used in combination with chemometric analysis for monitoring volatile organic compounds (VOCs) released from C. cacaofunesta. Low-molecular-weight esters, alcohols, ketones, and sulphur compounds were identified in the liquid broth. Monitoring the volatile profile over five days of fungal growth revealed that the concentrations of alcohol and esters were inversely proportional. Acetate esters were responsible for the intense fruity aroma of the C. cacaofunesta culture produced within the first hours after fungal inoculation, which decreased over time, and are likely associated with the attraction of insect vectors to maintain the life cycle of the pathogen. PCA revealed that 3-methylbutyl acetate was the metabolite with the highest factor loading for the separation of the VOC samples after 4 h of fungal growth, whereas ethanol and 3-methylbutan-1-ol had the highest factor loadings after 96 and 120 h. 3-Methylbutan-1-ol is a phytotoxic compound that is likely associated with host cell death since C. cacaofunesta is a necrotrophic fungus. Fungal VOCs play important roles in natural habitats, regulating developmental processes and intra- and interkingdom interactions. This is the first report on the volatiles released by C. cacaofunesta.

RESUMEN

Therapeutic drug monitoring (TDM) of imatinib (IM) in cancer therapy offers the potential to improve treatment efficacy while minimizing toxicity. There was a significant correlation between unbound concentration and clinical response and toxicity, compared with total plasma concentrations, and the quantification of unbound IM and its metabolite, N-desmethyl imatinib (NDI) are of interest for TDM. However, traditional unbound drug separation methods have shortcomings, especially are susceptible to non-specific binding (NSB) of drugs to the polymer-constructed components of filter membranes, which are difficult to avoid at present. Hence it is necessary to developed a reliable separation method for the analysis of the unbound fraction of IM and NDI in TDM. We developed and validated an hollow fiber solid phase microextraction (HF-SPME) method coupled with high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) that to measure unbound IM and NDI concentration in human plasma. It used the NSB phenomenon and solve the NSB problem. The preparation procedure only involves a common vortex and ultrasonication without dilution of samples and modification of membrane. A total of 50 chronic myeloid leukemia (CML) patients were enrolled in our study. The relationship between the unbound and total concentrations for IM and NDI, as well as the concentration ratios of NDI to IM in 50 clinical plasma samples were investigated. The extraction recovery is high to 95.5-106 % with validation parameters for the methodological results were all excellent. There were both a poor linear relationship between the unbound and total concentrations for IM (r2=0.504) and NDI (r2=0.201) in 50 clinical plasma samples. The unbound concentration ratios of NDI to IM varied widely in CML patients. The determination of unbound IM and NDI concentration is meaningful and necessary. The developed HF-SPME method is simple, accurate and precise that could be used to measure unbound IM and NDI concentration in clinical TDM.

Asunto(s)

RESUMEN

The present work describes a quick, simple, and efficient method based on the use of layered double hydroxides (LDH) coupled to dispersive solid phase micro-extraction (DSPME) to remove α-naphthol (α-NAP) and ß-naphthol (ß-NAP) isomers from water samples. Three different LDHs (MgAl-LDH, NiAl-LDH, and CoAl-LDH) were used to study how the interlayer anion and molar ratio affected the removal performance. The critical factors in the DSPME procedure (pH, LDH amount, contact time) were optimized by the univariate method under the optimal conditions: pH, 4-8; LDH amount, 5 mg; and contact time, 2.5 min. The method can be successfully applied in real sample waters, removing NAP isomers even in ultra-trace concentrations. The large volume sample stacking (LVSS-CE) technique provides limits of detections (LODs) of 5.52 µg/L and 6.36 µg/L for α-naphthol and ß-naphthol, respectively. The methodology's precision was evaluated on intra- and inter-day repeatability, with %RSD less than 10% in all cases. The MgAl/Cl--LDH selectivity was tested in the presence of phenol and bisphenol A, with a removal rate of >92.80%. The elution tests suggest that the LDH MgAl/Cl--LDH could be suitable for pre-concentration of α-naphthol and ß-naphthol in future works.

Asunto(s)

RESUMEN

Phthalate esters (PAEs) are used as additives to enhance the pliability and malleability of plastics. These substances frequently migrate from packaging materials to vegetable oils because of the absence of covalent bonds. Over time, this migration could result in the accumulation of PAEs in the human body through ingestion, contributing to various diseases. Therefore, accurate qualitative and quantitative analyses of PAEs in vegetable oils are imperative to assess the origins of contamination and investigate their toxicity, degradation, migration, and transformation patterns. However, the concentration of PAEs in most samples is low, and the composition of vegetable oils is complex. Thus, PAEs must be enriched and purified using appropriate sample pretreatment procedures before analysis. Common methods for pretreating PAEs in oil include solid-phase extraction (SPE), dispersive SPE, and magnetic SPE. These techniques require time-consuming and labor-intensive procedures such as oil dissolution, solvent extraction, and degreasing. These approaches also require numerous solvents and containers, increasing the risk of sample cross-contamination. Solid-phase microextraction (SPME) integrates sampling, extraction, purification, concentration, and injection into a single process, significantly accelerating analytical testing and reducing the potential for sample cross-contamination. In headspace (HS) mode, the analytes achieve equilibrium on the coating and are extracted in the gas phase. The fibers are shielded from nonvolatile and high-relative molecular mass substances in the sample matrix. Thus, SPME is an ideal method for extracting volatile compounds in vegetable oils. When HS-SPME coupled with gas chromatography-mass spectrometry (GC-MS), it can achieve the rapid screening of PAEs in vegetable oil. In this study, an SPME with cyclodextrin-based hypercrosslinked polymers (BnCD-HCP) coated on stainless steel fibers was employed to extract PAEs from vegetable oil. The structure and morphology of the polymers were characterized using Fourier-transform infrared spectroscopy, nuclear magnetic spectroscopy, and scanning electron microscopy. BnCD-HCP exhibited high stability and diverse interactions, including π-π, hydrophobic, and host-guest interactions. The oil samples were incubated with methanol, and the PAEs were extracted from the headspace using the probe. The optimal extraction parameters included an extraction time of 20 min, extraction temperature of 50 ℃, desorption time of 4 min, and desorption temperature of 275 ℃. The BnCD-HCP/HS-SPME method was evaluated under optimized experimental conditions. The limits of detection (LODs) and quantification (LOQs) were determined by applying signal-to-noise ratios (S/N) of 3 and 10, respectively. Method accuracy was evaluated using relative standard deviations (RSDs). Single-needle precision was evaluated by conducting three consecutive analyses at 3 h intervals within a day. Inter-needle precision was assessed by conducting the same analyses (three replicates) with differently coated fibers. The 12 PAE compounds exhibited good linearity with correlation coefficients (R2) of at least 0.99. The LODs and LOQs ranged from 0.21 to 3.74 µg/kg and from 0.69 to 12.34 µg/kg, respectively. The RSDs were in the range of 1.8%-11.4% and 5.1%-13.9% for the single-needle and needle-to-needle methods, respectively. The proposed method was applied to soybean, peanut, and sunflower oils, and two PAEs were found in all three oils. Moreover, the method demonstrated good precision (RSD=1.17%-11.73%) and recoveries (72.49%-124.43%). Compared with other methods, the developed method was able to extract many target analytes and had a low or comparable LOD and high recovery. More importantly, this method does not require tedious operations such as solvent extraction and purification. Consequently, the developed method can be used to extract not only PAEs in oils but also other substances with a high lipid content.

Asunto(s)

RESUMEN

Lipidomic profiling has been reported as an effective approach for characterizing and differentiating brain tumors. However, since lipids can undergo non-specific enzymatic and nonenzymatic reactions due to tissue disruption, it is critical to consider the preanalytical phase of the diagnostic process (e.g., optimizing the sampling time and sampling conditions). Thus, this study assesses the ways in which the time point of sampling impacts the lipidome composition of brain tumors. Two histologically distinct brain tumors-namely, meningiomas and gliomas-were sampled using solid-phase microextraction (SPME) fibers at two time points: on-site directly after removal, and after 12 months of storage at -30 °C. The samples were analyzed via HILIC chromatography coupled with HRMS, which enabled the detection of a wide range of features, including phospholipids and sphingolipids, as well as changes in the profiles of these compounds. The samples obtained from the stored tissues tended to have elevated levels of analytes with lower m/z values. In addition, the samples obtained from the fresh and stored tissues were easily distinguished based on their lipidome compositions, regardless of the histological tumor type. Notably, while storage did not affect the possibility of differentiating meningiomas and gliomas, the biological interpretation of the obtained results were prone to bias.

Asunto(s)

RESUMEN

Methyltrimethoxysilane (MTMS) modified tin dioxide microspheres (MTMS/SnO2) were prepared by a facile hydrothermal method and heated reflux reaction strategy. The characterization results indicate that the modification of MTMS induced the formation of a hydrophobic network within the composites, while maintaining abundant adsorbed oxygen species. Subsequently, the MTMS/SnO2 microspheres were used as a solid-phase microextraction (SPME) coating for the efficient extraction and sensitive determination of trace polychlorinated biphenyls (PCBs) in aqueous solutions coupled to gas chromatography-mass spectrometry. MTMS/SnO2 coating exhibited superior extraction performances for PCBs compared with commercial SPME and pure SnO2 microspheres coatings, owing to the hydrophobic crosslinking and adsorbed oxygen-enhanced hydrogen bonding. The proposed analytical method presented respectable linearity in the concentration range 0.25-1000 ng L-1, with low limits of detection varying from 0.036 to 0.14 ng L-1 for seven PCBs and excellent precision, with relative standard deviations of 5.7-9.8% for a single fiber and 8.2-13.1% for five fibers. Finally, the proposed method was successfully used for determination of PCBs in real water with recoveries ranging from 75.8 to 115.6%. This study proposed a new type SPME coating of MTMS/SnO2 microspheres, which extended the potential of SnO2 in capturing and determining organic pollutants.

RESUMEN

Characterization of chemical composition in cigarette smoke is essential for establishing smoke-related exposure estimates. Currently used methods require complex sample preparation with limited capability for obtaining accurate chemical information. We have developed an in situ solid-phase microextraction (SPME) method for online processing of smoke aerosols and directly coupling the SPME probes with confined-space direct analysis in real time (cDART) ion source for high-resolution mass spectrometry (MS) analysis. In a confined space, the substances from SPME probes can be efficiently desorbed and ionized using the DART ion source, and the diffusion and evaporation of volatile species into the open air can be largely avoided. Using SPME-cDART-MS, mainstream smoke (MSS) and side-stream smoke (SSS) can be investigated and the whole analytical protocol can be accomplished in a few min. More than five hundred substances and several classes of compounds were detected and identified. The relative contents of 13 tobacco alkaloids were compared between MSS and SSS. Multivariate data analysis unveiled differences between different types of cigarette smoke and also discovered the characteristic ions. The method is reliable with good reproducibility and repeatability, and has the potential to be quantitative. This study provides a simple and high-efficiency method for smokeomics profiling of complex aerosol samples with in situ online extraction of volatile samples, and direct integration of extracted probes with a modified ambient ionization technique.