Stir Bar Sorptive Extraction Research Articles

Development and Application of a Robust Imine-Based Covalent Organic Framework for Stir Bar Sorptive Extraction of Estrogens in Environmental Water

A covalent organic framework (COF) based on imine was synthesized using 2,5-dihexoxyterephthalaldehyde (DHT) and 1,3,5-tris(4-aminophenyl) benzene (TAPB) as starting materials. The TAPB-DHT-COF exhibited satisfactory chemical stability, making it a promising adsorbing material for stir bar sorptive extraction (SBSE) of four estrogens, including estrone (E1), β-estradiol (E2), hexestrol (HES), and mestranol (MeEE2), in ambient water samples. The extracted analytes were subsequently analyzed using a high-performance liquid chromatography-diode array detector (HPLC-DAD). A series of parameters affecting the SBSE process, such as solution pH, ionic strength, extraction time, and desorption solvent, were investigated by the controlled variable method. Under optimal conditions, the limit of detection (LODs) for the four targeted estrogens ranged from 0.06 to 0.15 µg/L, with a linear range from 0.2 to 100 µg/L. The observed enrichment factor (EF) ranged from 39 to 49, while the theoretical EF was estimated to be 50-fold. This methodology can be applied to the identification of estrogens in three environmental water samples.

Comparison of Removal Characteristics of Organophosphorus Flame Retardants Using Ozone and UV-Based Advanced Oxidation Processes in the Downstream of Nakdong River

Objectives : This study aimed to evaluate the removal efficiency of trace organic contaminants (TrOCs) in UVbased advanced oxidation processes (AOPs) as an alternative to the post-ozonation process in a drinking water treatment plant (DWTP) in the downstream of Nakdong River. The results are expected to be utilized as basic data for modernizing aging water treatment facilities.Methods : Eight organophosphorus flame retardants (OPFRs), known for their persistence and resistance to degradation, were selected as the target TrOCs for evaluating the efficiency of ozonation and UV-based AOPs. Experiments were conducted using sand-filtered water from a DWTP in the downstream of Nakdong River, with the OPFRs spiked into the sample matrix. Lab-scale experiments of ozonation and UV-based AOPs (UV, UV/H<sub>2</sub>O<sub>2</sub>, and UV/Cl<sub>2</sub>) were performed, and the concentrations of the OPFRs were analyzed using stir bar sorptive extraction (SBSE) system, followed by GC-MS/MS.Results and Discussion : The second-order rate constants (<i>k</i><sub>OH</sub>) for the reaction of OPFRs with OH radicals were estimated using the group contribution method and ranged from 1.4(±0.6)×10<sup>9</sup> to 1.8(±0.1)×10<sup>10</sup> M<sup>⁻1</sup> s<sup>⁻1</sup>, depending on their structural characteristics. In the ozonation process, the removal of Cl-containing aliphatic OPFRs was not effective, likely due to the electron-withdrawing effects of the -Cl groups, which inhibited their reactivity with both ozone and OH radicals. However, for non-Cl-containing aliphatic and aromatic OPFRs, more than 90% removal efficiency was achieved at a specific ozone dose of 1.5 mgO<sub>3</sub>/mgDOC. In the UV-based AOPs, the aliphatic OPFRs showed poor removal efficiency of 5~35% at a UV fluence of 1,000 mJ/cm<sup>2</sup> under direct UV photolysis. However, in the presence of oxidants (H<sub>2</sub>O<sub>2</sub> or free available chlorine), the UV/H<sub>2</sub>O<sub>2</sub> process showed up to an 89% increase in removal efficiency, and the UV/Cl<sub>2</sub> process exhibited up to a 49% increase. The difference in removal patterns between the UV/H<sub>2</sub>O<sub>2</sub> and UV/Cl<sub>2</sub> processes is likely attributed to the difference in reactivity between reactive chlorine species and aliphatic OPFRs. For aromatic OPFRs, direct UV photolysis achieved high enough removal efficiencies of 90~98% at a UV fluence of 1,000 mJ/cm<sup>2</sup>. These results demonstrate the potential of UV/H2O2 and UV/Cl<sub>2</sub> processes for the effective removal of OPFRs, particularly for Cl-containing aliphatic OPFRs, which exhibited low removal efficiency in the ozonation process.Conclusion : The comparative evaluation of removal efficiencies of OPFRs in ozone and UV-based AOPs confirmed the potential of UV processes for efficient removal of OPFRs. The UV/H<sub>2</sub>O<sub>2</sub> and UV/Cl<sub>2</sub> processes showed promise as alternative treatments to ozonation for the removal of OPFRs during drinking water treatment.

Recent Progress and Applications of Advanced Nanomaterials in Solid-Phase Extraction.

Sample preparation maintains a key bottleneck in the whole analytical procedure. Solid-phase sorbents (SPSs) have garnered increasing attention in sample preparation research due to their crucial roles in achieving high clean-up and enrichment efficiency in the analysis of trace targets present in complex matrices. Novel nanoscale materials with improved characteristics have garnered considerable interest across different scientific disciplines due to the limited capabilities of traditional bulk-scale materials. The purpose of this review is to offer a thorough summary of the latest developments and uses of SPSs in preparing samples for chromatographic analysis, focusing on the years 2020-2024. The techniques for preparing SPSs are examined, such as metal-organic frameworks (MOFs), covalent organic frameworks (COFs), carbon nanoparticles (CNPs), molecularly imprinted polymers (MIPs), and metallic nanomaterials (MNs). Examining the pros and cons of different extraction methods, including solid-phase extraction (SPE), magnetic SPE (MSPE), flow-based SPE (FBA-SPE), solid-phase microextraction (SPME), stir-bar sorptive extraction (SBSE), and dispersive SPE (DSPE), is the main focus. Furthermore, this article presents the utilization of SPE technology for isolating common contaminants in various environmental, biological, and food specimens. We highlight the persistent challenges in SPSs and anticipate future advancements and applications of novel SPSs.

Comparison of Different Solid-Phase Microextraction Formats Dedicated to the Analysis of Volatile Compounds-A Comprehensive Study.

The coupling of Solid-Phase Microextraction (SPME) technology with gas chromatography (GC) has a well-established and successful history. Traditionally, SPME fibers have been the most popular form thanks to their versatility and the ease with which they can be fully automated. However, alternative geometries for SPME have been developed over the years, beginning with Stir Bar Sorptive Extraction (SBSE) and later evolving into Thin-Film SPME (TF-SPME) devices. Each of these formats offers distinct advantages and disadvantages, which are explored in this study. The primary objective of this study was to comprehensively compare available forms of SPME devices, with a special focus on the advantages of TF-SPME, a novel microextraction method particularly suited for the analysis of odorants in food. The study involved analyzing a standard mixture of 11 key food odorants, representing a range of polarities, to evaluate the efficiency of TF-SPME devices in terms of the number of analytes extracted. Furthermore, four types of TF-SPME devices were compared against each other in both standard mixtures and actual food samples. The final stage of the study employed GCxGC-ToFMS analysis to showcase the potential of the most efficient HLB-TF-SPME device in the non-targeted analysis of complex samples, exemplified by unfiltered wheat beer. This analysis demonstrated the significant capability of HLB-TF-SPME in capturing and identifying a wide range of volatile compounds in complex matrices.

Trace analysis of taste and odour compounds in drinking water by stir bar sorptive extraction followed by thermal desorption - gas chromatography - mass spectrometry (SBSE-TD-GC-MS)

Because of negative tap water quality perception, people often prefer bottled water over tap water despite the higher energy consumption and production of plastic waste. Taste and odour (T&O) deviations in tap water are an important aspect of this issue and should be avoided. However, T&O compounds typically occur at low concentrations (≤ ng.L−1) and are numerous, originating from various sources, ranging from source water to kitchen taps. Consequently, unravelling T&O events is challenging and causing compounds may remain unknown. Therefore, a multi-compound method (SBSE-TD-GC–MS) was developed, optimised and validated for the simultaneous trace analysis of 45 T&O compounds in drinking water. It covers key compounds of different odour categories with a wide range of physical-chemical properties and originating from the different steps of production and distribution. The intra- and interday precision of the method was shown by relative standard deviations (RSD) lower than 15 % and 23 %, respectively, for 75 % of the measured concentrations. For most of the compounds (>75 %), the detection capability (CCβ) was below 1/3rd of their lowest reported odour threshold concentration (OTC), while for the other 6 compounds, the CCβ was within the reported OTC range. Additionally, the CCβs were comparable to or lower than those in literature. As a proof of concept, the method was used to investigate the occurrence and concentrations of T&O compounds before (surface water) and after drinking water production. The results show a clear removal of compounds related to microbial activity (e.g. geosmin, 2-methylisoborneol, 2,4,6-tribromoanisole) after treatment and an increase of compounds related to disinfection. Although rarely investigated, 3-methylbutanal showed concentrations similar to its OTC in treated drinking water, emphasizing the necessity of a broad ultra-trace analysis to ultimately prevent the occurrence of T&O compounds and guarantee tap water quality.

Evaluation of urinary volatile organic compounds as a novel metabolomic biomarker to assess chronic kidney disease progression

BackgroundThere is a need to develop accurate and reliable non-invasive methods to evaluate chronic kidney disease (CKD) status and assess disease progression. Given it is recognized that dysregulation in metabolic pathways occur from early CKD, there is a basis in utilizing metabolomic biomarkers to monitor CKD progression. Volatile Organic Compounds (VOCs), a form of metabolomic biomarker, are gaseous products of metabolic processes in organisms which are typically released with greater abundance in disease conditions when there is dysregulation in metabolism. How urinary VOCs reflect the abnormal metabolic profile of patients with CKD status is unknown. Our study aimed to explore this.MethodsIndividuals aged 18–75 years undergoing kidney biopsy were included. Pre-biopsy urine samples were collected. All biopsy samples had an interstitial fibrosis and tubular atrophy (IFTA) grade scored by standardized assessment. Urine supernatant was extracted from residue and sampled for stir bar sorptive extraction followed by Gas chromatography–mass spectrometry (GC-MS) analysis. Post-processing of GC-MS data separated complex mixtures of VOCs based on their volatility and polarity. Mass-to-charge ratios and fragment patterns were measured for individual VOCs identification and quantification. Linear discriminant analysis (LDA) was performed to assess the ability of urinary VOCs in discriminating between IFTA 0 (‘no or minimal IFTA’ i.e. <10%, IFTA), IFTA 1 (‘mild IFTA’ i.e. 10–25% IFTA) and IFTA ≥ 2 (‘moderate or severe IFTA’ i.e. >25% IFTA). Linear regression analysis adjusting for age, sex, estimated glomerular filtration rate, diabetes mellitus (DM) status, and albuminuria was conducted to determine significantly regulated urinary VOCs amongst the groups.Results64 study participants (22 individuals IFTA 0, 15 individuals IFTA 1, 27 individuals IFTA ≥ 2) were included. There were 34 VOCs identified from GC-MS which were statistically associated with correct classification between the IFTA groups, and LDA demonstrated individuals with IFTA 0, IFTA 1 and IFTA ≥ 2 could be significantly separated by their urinary VOCs profile (p < 0.001). Multivariate linear regression analysis reported 4 VOCs significantly upregulated in the IFTA 1 compared to the IFTA 0 group, and 2 VOCs significantly upregulated in the IFTA ≥ 2 compared to the IFTA 1 group (p < 0.05). Significantly upregulated urinary VOCs belonged to one of four functional groups - aldehydes, ketones, hydrocarbons, or alcohols.ConclusionsWe report novel links between urinary VOCs and tubulointerstitial histopathology. Our findings suggest the application of urinary VOCs as a metabolomic biomarker may have a useful clinical role to non-invasively assess CKD status during disease progression.

Suspended Stir Bar Sorptive Extraction Based on Zr-MOF-Modified Cotton Thread for Enrichment and Detection of Three Trace Quinolones in Fish Tissue.

In this study, an efficient and practical method was established to enrich and detect three trace quinolones in fish tissue. Low-cost and environment-friendly cotton threads were coated with PCN-224 using a simple one-pot hydrothermal method. The PCN-224-modified cotton threads (PCN-224@CTs) were characterized to ensure that the crystal was successfully fabricated on the surface of cotton threads. The prepared PCN-224@CTs were wrapped around steel needles to form suspended bars. Key factors of extraction and desorption were optimized, and analytical performance was tested. Suspended bar sorptive extraction coupled with ultra-performance liquid chromatography (UPLC) with a photodiode array detector was used to analyze the quinolones in fish tissue. The detection limits of quinolones were 0.26-1.15ng/mL, and the recoveries were achieved in the range of 81.31%-115.81%, indicating a simple method with high sensitivity and satisfactory practicability of enriching, separating, and detecting trace quinolones was successfully established.

Detection and Validation of Organic Metabolites in Urine for Clear Cell Renal Cell Carcinoma Diagnosis.

Clear cell renal cell carcinoma (ccRCC) comprises the majority, approximately 70-80%, of renal cancer cases and often remains asymptomatic until incidentally detected during unrelated abdominal imaging or at advanced stages. Currently, standardized screening tests for renal cancer are lacking, which presents challenges in disease management and improving patient outcomes. This study aimed to identify ccRCC-specific volatile organic compounds (VOCs) in the urine of ccRCC-positive patients and develop a urinary VOC-based diagnostic model. This study involved 233 pretreatment ccRCC patients and 43 healthy individuals. VOC analysis utilized stir-bar sorptive extraction coupled with thermal desorption gas chromatography/mass spectrometry (SBSE-TD-GC/MS). A ccRCC diagnostic model was established via logistic regression, trained on 163 ccRCC cases versus 31 controls, and validated with 70 ccRCC cases versus 12 controls, resulting in a ccRCC diagnostic model involving 24 VOC markers. The findings demonstrated promising diagnostic efficacy, with an Area Under the Curve (AUC) of 0.94, 86% sensitivity, and 92% specificity. This study highlights the feasibility of using urine as a reliable biospecimen for identifying VOC biomarkers in ccRCC. While further validation in larger cohorts is necessary, this study's capability to differentiate between ccRCC and control groups, despite sample size limitations, holds significant promise.

Mapping soil VOCs using three green sample extraction techniques and GC–MS

Sample preparation is a very crucial step prior to sample analysis. Three green adsorptive sample preparation micro-extraction techniques were investigated (smart solid-phase microextraction (SPME), high-capacity sorptive extraction (HiSorb), and stir bar sorptive extraction (SBSE)) for the determination of volatile organic compounds (VOCs) emitted from vineyard soil samples after method optimization. More specifically, the 95 μm Carbon Wide Range/Polydimethylsiloxane (CWR/PDMS) smart SPME fiber, CWR/PDMS HiSorb, and PDMS Twister micro-extraction tools were compared for their extraction capabilities. The headspace (HS)-SPME-gas chromatography-mass spectrometry (GC–MS) method was proved better for the extraction of VOCs from the vineyard soils due to shorter exposure time (45 min), its automation (use of a fully automated system compared to the other two), and the high sample throughput analysis. The validation of the HS-SPME-GC–MS method showed good linearity (R2 ≥ 0.9951) and limit of detection (LOD), whereas the limit of quantitation (LOQ) ranged from 0.04-3.65 μg/kg. Also, the repeatability and reproducibility of the results showed a relative standard deviation (RSD) lower than 4.73 %. A total number of 47 soil-derived VOCs were identified through the validated HS-SPME-GC–MS method, and 9 targeted VOCs were quantified with total average concentrations ranging from 0.14-28.07 µg/kg. Smart SPME fiber proved beneficial over the two other tools, highlighting the aspects of green chemistry.

An easy, low-cost and efficient method for the extraction of benzoic acid and sorbic acid from orange juice and cola soft drink based on PET plastic stir bar sorptive extraction

In this research, a simple, convenient and low-cost method was used for the simultaneous extraction of benzoic acid (BA) and sorbic acid (SA) with the help of stir bar sorptive extraction (SBSE) method followed by HPLC-UV. Polyethylene terephthalate (PET) was used to cover the stir bar. The source of PET was mineral water plastic bottles, which create a porous polymer coating after dissolving in trifluoroacetic acid (TFA) and mixing with polyvinylpyrrolidone (PVP). The simple strategy of converting waste PET plastic can not only reduce environmental pollution caused by microplastics, but also create an inexpensive and efficient material for coating of stir bar. The obtained polymer was identified by Fourier-transform infrared (FT-IR), field emission-scanning electronic microscope (FE-SEM), X-ray powder diffraction (XRD) and energy dispersion spectroscopy (EDS) techniques. After optimizing the factors affecting the extraction by Box-Behnken design and response surface methodology (RSM), a linear range of 10–7000 μg/L with a coefficient of determination (R2) of more than 0.9984 was obtained for the mentioned compounds. The detection limit for BA and SA was 6 and 5 μg/L, respectively. This method was successfully applied to measure BA and SA in cola soft drink and orange juice samples. The recovery of more than 92.4 % and the error of less than 5.1 % indicate the applicability of this method.

Developments and Applications of Molecularly Imprinted Polymer-Based In-Tube Solid Phase Microextraction Technique for Efficient Sample Preparation.

Despite advancements in the sensitivity and performance of analytical instruments, sample preparation remains a bottleneck in the analytical process. Currently, solid-phase extraction is more widely used than traditional organic solvent extraction due to its ease of use and lower solvent requirements. Moreover, various microextraction techniques such as micro solid-phase extraction, dispersive micro solid-phase extraction, solid-phase microextraction, stir bar sorptive extraction, liquid-phase microextraction, and magnetic bead extraction have been developed to minimize sample size, reduce solvent usage, and enable automation. Among these, in-tube solid-phase microextraction (IT-SPME) using capillaries as extraction devices has gained attention as an advanced "green extraction technique" that combines miniaturization, on-line automation, and reduced solvent consumption. Capillary tubes in IT-SPME are categorized into configurations: inner-wall-coated, particle-packed, fiber-packed, and rod monolith, operating either in a draw/eject system or a flow-through system. Additionally, the developments of novel adsorbents such as monoliths, ionic liquids, restricted-access materials, molecularly imprinted polymers (MIPs), graphene, carbon nanotubes, inorganic nanoparticles, and organometallic frameworks have improved extraction efficiency and selectivity. MIPs, in particular, are stable, custom-made polymers with molecular recognition capabilities formed during synthesis, making them exceptional "smart adsorbents" for selective sample preparation. The MIP fabrication process involves three main stages: pre-arrangement for recognition capability, polymerization, and template removal. After forming the template-monomer complex, polymerization creates a polymer network where the template molecules are anchored, and the final step involves removing the template to produce an MIP with cavities complementary to the template molecules. This review is the first paper to focus on advanced MIP-based IT-SPME, which integrates the selectivity of MIPs into efficient IT-SPME, and summarizes its recent developments and applications.

Green and sensitive method combining ultrasonic solvent extraction, stir bar sorptive extraction and thermal desorption-gas chromatography–tandem mass spectrometry for determination of organotin compounds in sediment

A method integrating ultrasonic solvent extraction (USE) and stir bar sorptive extraction (SBSE) with thermal desorption-gas chromatography–tandem mass spectrometry (TD-GC–MS/MS) was developed and validated for determining critical organotin compounds (OTCs)—tributyltin (TBT) and triphenyltin (TPhT)—in sediment. In preparing a 0.5 g sediment sample, two 1-min cycles of US bath solvent extraction (using equal parts CH3COOH and MeOH), were followed by derivatization with NaBEt4 in the presence of a methanolic-aqueous solution of CH3COONa and SBSE for 1 h, achieving analyte recoveries of 64–94 %. Matrix-matched internal standard calibration and the use of an isotopically labelled recovery standard corrected for analyte losses and matrix effect (ME), ensuring accurate results for triorganotins. However, the method was not suitable for mono- and diorganotins due to low and anomalous recoveries caused by ME. Miniaturizing and optimizing the sample preparation reduced chemicals use and waste, contributing to the method being deemed ’an excellent green analysis’ by the Analytical Eco-Scale assessment. The method achieved a limit of quantification (LOQ) of 0.081 ng g−1 and an expanded uncertainty (U) value of 15 % for TBT, meeting the environmental quality standards (EQS) criteria of the European Union Water Framework Directive. Its applicability was demonstrated through the analysis of actual sediment samples and natural matrix certified reference materials.

Green Analytical Method for Perfluorocarboxylic Acids (PFCAs) in Water of Stir Bar Sorptive Extraction Coupled with Thermal Desorption–Gas Chromatography—Mass Spectroscopy

Perfluoroalkyl carboxylic acids (PFCAs) are a significant group of per- and polyfluoroalkyl substances (PFASs). They are persistent organic chemicals manufactured for their resistance to heat, water, and stains. PFCAs are ubiquitous in the environment, particularly in surface water and wastewater, because they are widely used in everyday consumer products. This contamination poses a risk to drinking water supplies and human health, necessitating sensitive and effective analytical methods. Traditional liquid chromatography–tandem mass spectrometry (LC-MS/MS) is commonly used but involves complex sample handling and high costs. In this study, we developed an enhanced stir bar sorptive extraction (SBSE) method coupled with thermal desorption–gas chromatography–mass spectrometry (TD-GC-MS) for the analysis of PFCAs in water. This method demonstrates linearity, with R2 values from 0.9892 to 0.9988, and low limits of detection (LOD) between 21.17 ng/L and 73.96 ng/L. Recovery rates varied from 47 to 97%, suggesting efficient extraction. Compared to traditional methods, the developed SBSE technique requires only a 1 mL sample volume and minimal amounts of solvents, enhancing eco-friendliness and reducing potential contamination and handling errors. This method also demonstrated good precision and robustness across various water matrices. Overall, the developed method offers a precise, eco-friendly, and reliable approach for analyzing PFCAs in diverse water samples.

Application of new green evaluation tools to assess the environmental impact of analytical procedures based on solid phase microextraction techniques

In this comparative study, four green evaluation tools, blue applicability grade index (BAGI), Analytical GREEnness (AGREE), Green Analytical Procedure Index (GAPI), and Analytical Eco-Scale were evaluated to assess 16 selected analytical methods including fiber-solid phase microextraction, stir bar sorptive extraction, and thin film microextraction joint to gas and liquid chromatographic as well as spectrofluorimetry techniques. The required parameters and data were extracted from the selected articles and calculations were performed based on the unique evaluation protocol of each tool. A uniform approach was applied in calculations and evaluations. A comparison of selected methods was done by determining the factors affecting greenness. High energy consumption, organic solvents, waste generation, analysis throughput, and the number of determined analytes, are among the crucial parameters that require improvement in the selected methods. The results show that using more than one evaluation tool in evaluating the greenness of analytical methods is very effective in obtaining synergistic results and increasing the understanding of the greenness of analytical methods.

Mechanism of the interaction between olfactory receptors and characteristic aroma compounds in sweet orange juice

The aroma compounds of three varieties of orange juice were extracted using solvent-assisted flavor evaporation (SAFE) and stir bar sorptive extraction (SBSE). A total of 41 aroma compounds were identified by gas chromatography-olfactometry (GC-O), among which 10 aroma compounds had an aroma intensity (AI) > 4.5. There were 53 aroma compounds identified by gas chromatography-mass spectrometry (GC-MS), 29 of which had an odor activity value (OAV) higher than 1. The findings indicated that (+)-limonene, linalool, hexanal, citral and myrcene were closely associated with the five characteristic aromas of orange juice. Furthermore, molecular docking was used to analyze the binding energies and interactions between these compounds and olfactory receptors (OR1A1, OR1D2, OR2W1, OR5AC2, OR1A2, and OR5M3). The average binding energies for these compounds at the six receptors were −6.2 kcal/mol, −6.0 kcal/mol, −5.8 kcal/mol, −5.1 kcal/mol, −6.3 kcal/mol and −4.7 kcal/mol, respectively. Hydrophobic interaction was a significant driving force in this process. Key residues such as Leu199 (OR1D2), Ala108 (OR1A2), Gly108 (OR2W1), Pro181 (OR5M3), Tyr261 (OR5AC2), and Val203 (OR1A1) played key roles in binding with characteristic aroma compounds. The formation mechanism of orange juice aroma was revealed, which provides theoretical guidance for the regulation of sweet orange aroma and flavor.

Variation in the Aroma Composition of Jasmine Tea with Storage Duration.

This study investigated the changes in the aroma of jasmine tea during storage. Solid-phase micro-extraction (SPME)-gas chromatography (GC)-mass spectrometry (MS) and stir bar sorptive extraction (SBSE)-GC-MS were combined to detect all volatile compounds. GC-olfactometry (GC-O), odor activity value (OAV), and p-value were employed to analyze and identify the key aroma compounds in six jasmine tea samples stored for different durations. Nine key aroma compounds were discovered, namely (Z)-3-hexen-1-yl acetate, methyl anthranilate, methyl salicylate, trans-β-ionone, linalool, geraniol, (Z)-4-heptenal, benzoic acid methyl ester, and benzoic acid ethyl ester. The importance of these compounds was confirmed through the aroma addition experiment. Correlation analysis showed that (Z)-4-heptenal might be the main reason for the increase in the stale aroma of jasmine tea. Through sensory evaluation and specific experimental analysis, it can be concluded that jasmine tea had the best aroma after 3 years of storage, and too long a storage time may cause the overall aroma of the tea to weaken and produce an undesirable odor. The findings can provide a reference for the change in aroma during the storage of jasmine tea and provide the best storage time (3 years) in terms of jasmine tea aroma.

Advances and Applications of Hybrid Graphene-Based Materials as Sorbents for Solid Phase Microextraction Techniques.

The advancement of traditional sample preparation techniques has brought about miniaturization systems designed to scale down conventional methods and advocate for environmentally friendly analytical approaches. Although often referred to as green analytical strategies, the effectiveness of these methods is intricately linked to the properties of the sorbent utilized. Moreover, to fully embrace implementing these methods, it is crucial to innovate and develop new sorbent or solid phases that enhance the adaptability of miniaturized techniques across various matrices and analytes. Graphene-based materials exhibit remarkable versatility and modification potential, making them ideal sorbents for miniaturized strategies due to their high surface area and functional groups. Their notable adsorption capability and alignment with green synthesis approaches, such as bio-based graphene materials, enable the use of less sorbent and the creation of biodegradable materials, enhancing their eco-friendly aspects towards green analytical practices. Therefore, this study provides an overview of different types of hybrid graphene-based materials as well as their applications in crucial miniaturized techniques, focusing on offline methodologies such as stir bar sorptive extraction (SBSE), microextraction by packed sorbent (MEPS), pipette-tip solid-phase extraction (PT-SPE), disposable pipette extraction (DPX), dispersive micro-solid-phase extraction (d-µ-SPE), and magnetic solid-phase extraction (MSPE).

Integration of miniaturized sample preparation and molecularly imprinted polymers in food analysis

The use of innumerable chemical compounds in food production to enhance agricultural quality and yield has raised significant global concerns regarding food safety. To address these concerns, miniaturized solid sample preparation techniques have emerged as an appealing strategy for analyzing chemical residues in complex samples, notably those found in food matrices. The efficacy of these miniaturized solid extraction procedures hinges largely on the choice of the sorbent phase. Molecularly imprinted polymers (MIPs) have been introduced as highly selective and versatile sorbent phases for a wide range of miniaturized solid techniques. Their remarkable selectivity is attributed to the creation of distinct cavities during the synthesis process, which subsequently accommodate the target analyte when the sample is applied. This unique characteristic empowers MIP polymers to exhibit exceptional specificity toward the desired analyte. The use of MIPs as sorbent phases in miniaturized sample preparation methods has shown great potential to increase the analytical performance of residue evaluation in food matrices. Therefore, here we present a comprehensive overview of the current landscape of miniaturized solid sample techniques employing MIPs as sorbent phases for the assessment of residues in food samples. Moreover, this review is primarily on recent reports concerning the application of MIPs in solid-phase microextraction (SPME), in-tube SPME, microextraction by packed sorbent (MEPS), disposable pipette extraction (DPX), solid-phase extraction in pipette tip (SPE-PT) and stir bar sorptive extraction (SBSE). Lastly, we will bring some future topics concerning the use of MIPs in miniaturized sample preparation methods for food analysis in order to bring some new avenues for enhancing food products' safety and quality assessment.

Comparison and application of the extraction methods for the determination of pharmaceuticals in water and sediment samples

Due to increasing consumption and production, pharmaceuticals are omnipresent in the environment. Regardless of whether they are present in low concentrations, their detection in the environment is of great concern for human health. Due to the appearance of new pharmaceuticals on the market, there is always a need to develop new analytical methods to determine their presence in various environmental samples. So, in this paper, new LC-MS/MS method was developed for the determination of 13 pharmaceuticals (azithromycin, tiamulin, imatinib, febantel, torasemide, omeprazole, linezolid, praziquantel, etodolac, sulfamethazine, sulfafurazole, albendazole, levamisole) in water and sediments samples.Pharmaceuticals were isolated from water by solid-phase (SPE) and stir-bar sorptive extraction (SBSE), while extracts from sediment samples were obtained by matrix-solid phase dispersion (MSPD) and ultrasound-assisted extraction (UAE). After optimization of extraction conditions, the methods were validated in terms of linearity, LOQ, LOD, precision, recovery and matrix effect. The LOQ of the optimized method were 2.5 ng/L-0.5 µg/L for SPE extraction and 0.1–10 µg/L for SBSE extraction from water, and 2.5 ng/g-25 μg/g for MSPD extraction and 0.025 do 5 µg/g for UAE extraction from sediment depending on the pharmaceuticals. Recoveries were matrix dependent (20–150 %), particularly for SBSE extraction and at the lowest investigated concentration tested, so standard addition calibrations were required for quantification in real samples. The standard addition calibration lines showed high linearity (R2 > 0.97) and replicate extractions showed good reproducibility (RSD≤%).Results obtained show that SPE is much more sensitive than SBSE, while for extraction from sediments both methods are equally sensitive, whereas for some tested pharmaceuticals MSPD is better and for others UAE is better. By comparing the sample preparation methods used, attention is drawn to the fact that, despite the large number of possible methods, not all of them are always equally good with regard to the target components and the type of sample.

Volatile profiles of Murcott and Ponkan mandarins obtained by stir bar sorptive extraction technique and their contributions to the fruit aroma.

Citrus species have undergone immense diversification ever since their ancestral origin. Ponkan and Murcott are two mandarin varieties widely consumed in Brazil and their aroma producing active compounds have not yet been extensively investigated. The present study analyzed the volatile constituents of the Ponkan and Murcott varieties employing the stir bar sorptive extraction (SBSE) technique and gas chromatography-mass spectrometry (GC-MS) analysis for the first time. Extraction was performed using the two phases of Twister bar, polydimethyl siloxane (PDMS), and ethylene glycol (EG) silicone in immersion and headspace modes. Among the detected 62 compounds comprising alcohols, aldehydes, esters, terpenes, and others identified, 55 and 37 compounds in the Ponkan and Murcott variety were determined, respectively, from both immersion and headspace modes using the two phases of Twister bar. From the odor active values, the Ponkan was characterized with the domination of compounds such as hexanal, decanal, nonanal, (E)-2-hexanal, ethyl hexanoate, d-limonene, linalool, and geraniol. Similarly, the Murcott variety was characterized with predominant compounds, namely, nonanal, octanal, hexanal, (E)-2-hexanal, ethyl hexanoate, d-limonene, and linalool. The profile of volatile compounds was found to be unique in both the varieties studied, and SBSE technique with GC-MS analysis favored the characterization of their respective profile due to the high amount of phase in the Twister bars, when compared to similar techniques, like solid phase microextraction. The PDMS Twister bar showed better capacity of adsorption of volatile compounds, since it is a relatively low-polarity polymer, which discriminates less analytes with different structures and polarities sampled from complex matrices, such as fruits juice.