Search

Cyclic volatile methylsiloxane (cVMS) is extensively used in consumer products and frequently detected in various environmental media, including water and air. In this study, we developed reliable and convenient methods to sample three cVMS compounds: octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6) in water and air samples collected from different tanks within a wastewater treatment plant (WWTP). The concentrations of D4, D5, and D6 in the water samples ranged from 0.40 to 8.0 μg L -1 , 0.35 to 91 μg L -1 , and 0.54 to 17 μg L -1 , respectively. In the air samples, these concentrations varied from 0.34 to 20 μg m -3 , 0.34 to 128 μg m -3 , and 0.08 to 12 μg m -3 , respectively. It is worth noting that the air-water distribution coefficient (K aw ) for these three cVMS exhibited a strong correlation with their water solubility. Moreover, fugacity fractions indicated a net evaporation process from water to the atmosphere. Furthermore, we investigated the distribution of cVMS between the gaseous and particulate phases. The results revealed a significant fraction, exceeding 72 %, of cVMS resided in the gas phase. D4 and D5 predominate in the gaseous phase, while D5 and D6 are the principal constituents within the particulate phase. The distribution coefficient characterizing the partitioning of cVMS compounds between the gaseous and particulate (K p ) exhibited a strong correlation with their corresponding octanol-air partitioning coefficients (K oa ). These findings contribute to a better understanding of the distribution of cVMS in diverse environmental media and the underlying mechanism governing their dispersion., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

In recent years, bile acids (BAs), the important component of bile, were found closely related to the occurrence and development of diseases, therefore, determination of BAs in bile samples is of great significance. However, biological matrix complexity and low concentrations of BAs were still challenging for BA detection in small amount of bile samples. In this work, a core-shell NH 2 -MIL101@mSiO 2 was designed to improve the capture ability of BAs in biological samples, as well as possess good biocompatibility. Subsequently, solid-phase microextraction (SPME) probe of the NH 2 -MIL101@mSiO 2 was coupled with HPLC-MS/MS to establish the analysis method for detecting eight BAs in bile samples. The established method received extraction efficiencies of (30-2143)-fold higher than those of the commercial probes and low limit of detection (LOD ≤ 0.21 ng mL -1 ). The miniaturization of SPME sampling devices, as well as the low LOD of this work, endowed this method advantage of low consumption of bile samples (30 μL). Based on the proposed method, eight BAs in bile samples of pancreatic cancer patients and cholelithiasis patients were detected successfully. A distinct difference was found in the concentrations of four targeted BAs in bile samples from pancreatic cancer patients and cholelithiasis patients. This work provided a method for quantification of eight BAs in small volume human bile samples, and it could open up a perspective regarding the relationship between BA metabolism and the occurrence of diseases., Competing Interests: Declaration of Competing Interest There is no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Emerging contaminants (ECs), especially antibiotics, have significantly polluted the environment and threaten the living circumstance of organisms. Environmental metabolomic has emerged to investigate the sublethal effects of ECs. However, lacking noninvasive and real-time sample pretreatment techniques restricts its development in environmental toxicology. Hence, in this study, a real-time and in vivo untargeted analytical technique towards microbial endogenous metabolites was developed via a novel composite solid-phase microextraction (SPME) fiber of ZIF-67 and polystyrene to realize the high-coverage capture of living gut microbial metabolites. To reveal the exposure risks of typical antibiotic - norfloxacin (NFX) to gut bacteria, four representative bacteria were exposed to NFX at environmentally relevant levels. Using the proposed SPME fiber, 70 metabolites were identified to obtain an apparent metabolic separation feature between control and NFX-treated (10 ng/mL) microbial groups, which revealed that the low environmental relevant concentration of NFX would affect normal metabolism of gut bacteria. Additionally, NFX exhibited species-specific toxic effects on microbial growth, especially Escherichia coli displaying a distinct dose-dependent trend. Antioxidative enzymatic activities results demonstrated that beneficial bacteria maintained the state of oxidative stress while symbiotic bacteria suffered from oxidative stress injury under NFX contamination, further corroborating its impact on human intestinal health. This study highlights the suitability of in vivo SPME in the field of metabolite extraction and simultaneously possesses a brilliant application foreground in the environmental metabolomics., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

High detection frequency of illicit drugs in water samples urges the development of rapid detection method for wastewater-based epidemiology (WBE) study. Here, we first developed a fast, convenient, and cost-effective method by combining thin-film microextraction (TFME) with gas chromatography-mass spectrometry (GC-MS) for sensing illicit drugs in wastewater sample. A divinylbenzene particle-loaded membrane was prepared by dip coating on a copper mesh. The sampling conditions of three illicit drugs were optimized and the performance of the proposed method was evaluated. The limit of detection was 5.5 2.0, and 1.1 ng L -1 for methamphetamine (MAMP), ketamine (KET), and methaqualone (MEQA), respectively, with acceptable precision (< 6.1 % for membrane to membrane reproducibility) and recovery from influent water (95 % - 111 %). Then, the proposed method was applied to study the occurrence and distribution of the target compounds in a wastewater treatment plant. The presence of methamphetamine, ketamine, and methaqualone was confirmed and their concentrations in the influent sample were 57 ± 8, 40 ± 4, and 75 ± 2 ng L -1 , respectively. The speciation of the target compounds in different ponds was also investigated. Results showed that the content of organic matter and the pH of the sample significantly affected the binding state of the compounds. This work provides an efficient and accurate analytical protocol for WBE investigation of illicit drugs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Objectives: To determine the sex-specific associations of handgrip strength (HGS) and asymmetry with incident multimorbidity and examine whether these relationships differ by sex., Design: Prospective cohort study., Setting and Participants: Secondary analyses of data from the English Longitudinal Study of Ageing (ELSA, waves 2-8). The analytic sample included 3977 participants (51.4% female) aged ≥50 years who had data for HGS on both hands and were living without multimorbidity at baseline., Measures: HGS was assessed with a handheld dynamometer. Individuals in the lowest tertile of sex-specific age-adjusted HGS were defined as having low HGS. The largest HGS readings from the nondominant and dominant hand were used to calculate HGS ratio [nondominant HGS (kg)/dominant HGS (kg)]. Those with HGS ratio <0.90 or >1.10 had any HGS asymmetry. Further, those with HGS ratio <0.90 had dominant HGS asymmetry, whereas those with HGS ratio >1.10 had nondominant HGS asymmetry. Multimorbidity was defined as the coexistence of ≥2 chronic diseases. Cox proportional hazards regression models were conducted for analyses., Results: Low HGS was associated with multimorbidity among older men [hazard ratio (HR) 1.20, 95% confidence interval (CI) 1.03-1.40] and women (HR 1.19, 95% CI 1.03-1.38). No significant effect modification by sex was observed (P-interaction = .71). HGS asymmetry increased the risk of multimorbidity in women only (HR 1.23, 95% CI 1.07-1.41). The relationship between HGS asymmetry and multimorbidity risk differed by sex (P-interaction = .01). Similarly, both dominant HGS asymmetry (HR 1.21, 95% CI 1.05-1.40) and nondominant HGS asymmetry (HR 1.32, 95% CI 1.03-1.68) were related to incident multimorbidity in women only. There was a significant interaction between dominant HGS asymmetry and sex (P-interaction = .02)., Conclusions and Implications: Examining HGS asymmetry in HGS test protocols can provide novel insights for the predictive power of HGS in the accumulation of diseases, particularly in women., (Copyright © 2021 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.)

This paper mainly focuses on the feasibility of rapidly identifying Fritillariae cirrhosae varieties, distinguishing its authenticity and detecting its components by using a portable near infrared (NIR) spectrometer. Five different varieties of Fritillariae cirrhosae, five common counterfeits and two main components (ethanol-soluble extractives and total alkaloids) were studied. The reference values of ethanol-soluble extractives were determined by hot dip method and the reference value of total alkaloid was determined by ultraviolet-visible spectrophotometry (UV-Vis). Linear discriminant analysis (LDA) algorithm was used to identify the sources of different varieties of Fritillariae cirrhosae and the common counterfeits of Fritillariae cirrhosae, respectively. As a result, the best models seemed to be effective, with accuracy of the two models' prediction sets reaches 83.33% and 90.91%, respectively. The partial least squares regression (PLSR) algorithm was used to relate the sample spectra with the reference values of ethanol-soluble extractives and total alkaloid content. Coefficient of determination of prediction (R 2 p) and root mean square errors of prediction (RMSEP) obtained were 0.8562 and 0.3911; 0.6917 and 0.0117, for ethanol-soluble extractives and total alkaloid content, respectively. The results showed that the portable NIR spectrometer could evaluate the quality of Fritillariae cirrhosae with high efficiency and practicability., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Although both dynapenia and abdominal obesity have negative impact on physical function and health, few prospective studies evaluate the association of dynapenic abdominal obesity (D/AO) with gait speed and falls. Our aim was to examine the combined effect of low muscle strength and abdominal obesity on long-term gait speed and falls in older adults., Methods: We used longitudinal data from the English Longitudinal Study of Ageing (ELSA), including 4987 individuals aged 60 years and over. Grip strength and waist circumference were measured at baseline. Gait speed and fall events (falls, recurrent falls, and fall-related injury) were evaluated during a 14-year follow-up. The study population were divided into nondynapenic nonabdominal obesity (ND/NAO), nondynapenic abdominal obesity (ND/AO), dynapenic nonabdominal obesity (D/NAO), and D/AO, according to the sex-specific grip strength (<16 kg for women and <26 kg for men) and waist circumference (>88 cm for women and >102 cm for men). We used generalized estimating equation (GEE) model with gait speed as the outcome and cox proportional hazards models with fall events as the outcome., Results: GEE model showed that gait speed decreased during the 14-year follow-up in all groups (all P time  < 0.001). Participants with ND/AO, D/NAO, and D/AO at baseline exhibited a worse gait speed than those with ND/NAO (all P group  < 0.001). No significant difference in the rate of gait speed decline between four groups was found (P group×time  = 0.062). Cox regression analysis showed that D/NAO and D/AO highly predicted falls, and the hazard ratio (HR) was 1.181 (95% CI: 1.002, 1.392) for D/NAO and 1.195 (95% CI: 1.006, 1.421) for D/AO. D/AO was the unique condition associated with recurrent falls and fall-related injury, and the HRs were 1.276 (95% CI: 1.018, 1.599) and 1.348 (95% CI: 1.066, 1.704), respectively., Conclusion: Dynapenia abdominal obesity, determined by low grip strength and high waist circumference, exhibits worse gait speed and increases the risk of fall events in older adults. Effort to maintain the mobility should focus on improving muscle strength and reducing excess body fat., (Copyright © 2021 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.)

Microplastics (MPs) can adsorb toxic chemicals in biological or environmental matrixes and thus influence their behavior and availability. In order to investigate how the combined pollution of MPs and toxic organic chemical influence microbial growth and metabolism, Escherichia coli (E. coli) was grown in a complex, well-defined media and treated with polystyrene microplastics (PS MPs) and dichloro-diphenyl-tricgloroethane (DDT) at human relevant concentration levels. In vivo metabolites captured by a novel solid phase microextraction (SPME) probe, were used to reflect the metabolic dysregulation of E. coli under different pollution stresses. Results showed that the toxic effect of DDT displayed a distinct dose-dependent phenomenon while the existence of PS decreased the growth and metabolic interference effect of DDT on E. coli. Adsorption results revealed a mechanism that PS weakened the adverse impact of DDT by decreasing its free concentration in the treated culture media. Tricarboxylic acid (TCA) cycle related enzymes activities and antioxidant defense related substances of E. coli also proved the mechanism. The current study is believed to broaden our understanding of the ecotoxicity of MPs with toxic organic chemicals on microorganism., (Copyright © 2020 Elsevier B.V. All rights reserved.)

For decades, researches have been involving in improving and optimizing solid-phase microextraction (SPME) technique to fit the growing environmental analysis demand. But it is more significant now to introduce meaningful information into the analysis line instead of improving every step in SPME. Herein, we design a carbon dots (CDs) based SPME platform and report its unique application in selective early screening and sensitive detection of 2-nitroaniline. The fluorescence quenching state of the CDs fiber after extraction could be used to prejudge whether an environmental sample contains 2-nitroaniline exceeding the maximum permitted level (30 μg L -1 ) regulated by the Chinese Ministry of Environmental Protection or not. Photo-induced electron transfer (PET) is believed to be the primary quenching route that leads to electron transfer from the electron-rich CDs to the electron-deficient analyte. A preliminary in vivo study on Daphnia magna and a 2-nitroaniline assay in environmental water and biofluid samples suggested the safety and the excellent qualitative ability of the proposed platform. As a result, the innovative incorporation of fluorescence sensing and SPME not only achieves the information imbedding of environmental analysis system, but also combines the advantages of two techniques including early visual-screening, reusability (≥50 times), high specificity and excellent quantitative ability (detection limit: 0.011 μg L -1 ). We believe this study can open new avenues in the field of environmental toxicant monitoring., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The Debao pony is a well-known dwarf horse breed in China. High-mobility group AT-hook 2 (HMGA2) gene is regarded as one of the important candidate genes regulating body height in horses. The aim of this study was to study the association between mutations in HMGA2 gene and withers height in Debao ponies. The polymorphisms in all exons and partial introns of the HMGA2 gene were screened with sequencing across 180 Debao ponies. And the association between the DNA variants and withers height was analyzed. Seven genetic variants were identified in HMGA2 gene, including six novel variants. Among them, six mutations were located in two closed linked blocks. The three novel variants (In1-1, E5-1, and E5-2) in the 1st intron and the fifth exon and a known mutation (In1-2) had significant association with withers height in Debao ponies. These results suggest that the four variants have the potential to be used as genetic markers for dwarf horse breeding activities., (Copyright © 2020 Elsevier Inc. All rights reserved.)

The exploitation of desired materials with specific properties for water remediation has become an irresistible trend. Generally, materials favorable to the elimination of hazardous contaminants are always beneficial to the detection of these compounds. Nevertheless, few researches combined these two procedures into a treating line. Therefore, a Prussian blue nanoparticles-doped graphene oxide (PBGO) composite was successfully synthesized and prepared as a solid-phase microextraction (SPME) coating for pollutant detection and a three-dimensional (3D) aerogel for contaminant removal in this study. Owing to its highly conjugated structure, abundant oxygen sites and periodical cyano groups, the composite achieved satisfactory enrichment capacity towards specific pollutants. The combination of elimination and determination of organic contaminants by using the PBGO composite not only possessed satisfactory performance but also avoided the separation process and secondary pollution. Finally, the PBGO SPME coating was utilized for the sensitive detection of several hazardous contaminants in environmental water samples with satisfactory recoveries. We think the combination of a PBGO composite with the green sample pretreatment technique (SPME) and pollutant elimination will not only help to facilitate the improvement in analytical fields, but also provide a secondary pollution-free way to explore the adsorption properties of adsorptive materials for environmental contaminants., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Analysis of organic pollutants is usually accomplished in centralized laboratories. However, the time-delayed and time-consuming process is insufficient and risky for precisely detection due to the contamination of vials, the losses of analytes during transportation and storage. Herein, a rapid and highly sensitive on-site detection approach was developed without using any vials by coupling an on-site pre-equilibrium solid phase microextraction (SPME) sampling method with a portable gas chromatography mass spectrometer (portable GC-MS), for the determination of three families of persistent organic pollutants (polychlorinated biphenyls, organochlorine pesticides and polycyclic aromatic hydrocarbons). Based on sampling-rate (SR) calibration method, the concentrations of target analytes in aquatic systems could be easily determined. Limits of detection (LODs) in the low parts-per-tillion levels (≤5.25 ng·L-1) were obtained for most of the investigated analytes with a total analysis time only ∼30 min. The proposed on-site detection approach was then successfully applied in the determination of persistent organic pollutants in real aquatic environment. A comparable result obtained by liquid extraction (LE) equipped with laboratorial GC-MS demonstrated the accuracy of the on-site detection method. In general, this study demonstrated a rapid and highly sensitive on-site approach, avoiding any risks of contamination during sampling and analysis, for determination of POPs as well as the potential applications for other organic pollutants in aquatic phase., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Recent works of designing excellent adsorbents emphasized on the specific surface areas and porosities of the materials. This study presents the influence of morphological modulation on extraction efficiencies of materials for the first time. Sea urchin-like nanoporous carbon (NPC), derived from metal organic framework (MOF), was synthesized and fabricated as solid phase microextraction (SPME) device. The morphological modulated structure of the NPC, with enhanced effective adsorption sites produced by the pointed and sharp edges, could improve the extraction efficiencies of the NPC. Comparing with the unmodulated one, NPC with morphological modulation possessed higher extraction efficiencies (2 flod) as well as accelerated sampling rates (5 flod) on benzene series compounds (BTEX), improving the sensitivity of the sampling method (limits of detection ranged from 0.08 ng L -1 to 0.36 ng L -1 ). Moreover, it was also the first time that the moisture sensitive MOF-derived NPC was exploited as the SPME adsorbent. In general, this study was expected to be an important advance in broadening the approaches on designing a superior SPME adsorbents not only emphasizing on the specific surface area as well as porosity but also the morphology., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Fluorescent carbon nanoparticles (FCNPs) have been deeply researched and widely applied in recent years due to their good optics performance, chemical stability and biocompatibility. Herein, a green and rapid microwave-assisted solid-phase synthesis (solvent-free) approach was proposed for the fabrication of highly FCNPs in a very short period of time, 4 min. The as-prepared FCNPs can emit a blue emission with quantum yield of up to 63.2% in water solution and show yellow fluorescence in the solid state. The FCNPs also exhibit special solvent effect that the fluorescence emission can be adjusted by controlling the solvent ratio of ethanol and water. Most importantly, the FCNPs possess a narrow-range pH response. The probe responds linearly and rapidly to minor pH fluctuations within the range of 3.47-5.10 and the correlation coefficient is above 0.99. The proposed FCNPs also exhibit high photostability and reusability. As expected, the cell imaging and intracellular pH monitoring was achieved successfully in living SMMC 7721 hepatoma cells by this probe. The FCNPs is promising as a convenient and general fluorescent pH sensor for bioimaging applications., (Copyright © 2018. Published by Elsevier B.V.)

Sensitivity and selectivity of the solid phase microextraction (SPME) in analysis are mostly determined by the coating material of the fiber used. Graphene oxide (GO) has attracted great attention because of its large specific surface area, rich oxygen functional groups, good dispersibility in aqueous solution and high reactivity. However, the low thermal stability of the functional groups limits the wide application of GO in SPME coating design. Highly cross-linked polyoxyethylene (POE) is a substrate widely used for composite material construction, which could significantly improve the thermal stability, water resistance as well as biocompatibility of the functional materials. In this study, we incorporated GO with highly cross-linked POE as a novel fiber coating material for SPME through the gluing approach. The obtained fiber possessed a wrinkled shape surface, which could increase the accessible surface area. In addition, the thermal and chemical stability of the fiber coating were also improved, rendering the fiber rigid enough for more than 100 repetitive extraction cycles. The performance of this developed SPME method for phenols was evaluated by headspace extraction of phenols in aqueous samples. Compared with three commercial fibers, the home-made fiber showed excellent extraction efficiencies towards phenols. Under the optimized conditions, it showed low detection limits (0.12-1.36 ng· L -1 ), good precision (<8.4%), good fiber-to-fiber repeatability (3.1%-8.1%), wide linear range (almost 5-1000 ng·L -1 and correlation coefficients (R 2 ) >99%), as well as good enrichment efficiencies (enrichment factors (EFs), 172-1752). Furthermore, the method was successfully applied in simultaneous analyses of five phenols for real water samples with satisfactory recoveries (81-113% for the Pearl River samples)., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The introduction of functional groups into metal organic frameworks has great potential for enhancement in adsorption performance of nitrosamines using solid phase microextraction (SPME). However, pre-functionalization and post-modification generally suffer from the same limitation that the additional functional groups occupy the free volume and thereby decreasing pore volume and special surface area. Herein, we use a modulator-induced defect-formation strategy to prepare the 8-aminocaprylic acid doped UIO-66 (Am-UIO-66) with high adsorption capacity of nitrosamines. Then, the as-synthesized UIO-66 and Am-UIO-66 were fabricated as SPME fibers exhibiting good adsorption capacity towards nitrosoamines. The reason was that the 8-aminocaprylic acid creates structural defects and additional pore spaces of Am-UIO-66, thus increases the specific surface area as well as pore volume. Finally, the Am-UIO-66-coated SPME fiber was successfully applied to the determination of nitrosamines migration from latex gloves and achieved good linearity (20-2000ngL -1 ), satisfactory recoveries (85.2-112.8%) and rather low LODs (2.61-6.12ngL -1 ), by coupling with gas chromatography-mass spectrometry (GC-MS)., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Adsorption capacity is the major sensitivity-limited factor in solid-phase microextraction. Due to its light-weight properties, large specific surface area and high porosity, especially tunable pore structures, the utilization of porous organic polymers as solid-phase microextraction adsorbents has attracting researchers' attentions. However, these works mostly concentrated on the utilization of specific porous organic polymers for preparing high-performance solid-phase microextraction coatings. The relationship between pore structures and adsorption performance of the porous organic polymers still remain unclear. Herein, three porous organic polymers with similar properties but different pore distributions were prepared by condensation polymerization reaction of phloroglucinol and terephthalaldehyde, which were fabricated as solid-phase microextraction coatings subsequently. The adsorption capacity of the porous organic polymers-coated fibers were evaluated by using benzene and its derivatives (i.e.,benzene, toluene, ethylbenzene and m-xylene) and polycyclic aromatic hydrocarbons as the target analytes. The results showed that the different adsorption performance of these porous organic polymers was mainly caused by their different pore volumes instead of their surface areas or pore sizes. Finally, the proposed method by using the mesoporous organic polymer coating was successfully applied to the determination of benzene and its derivatives in environmental water samples. As for analytical performance, high pre-concentration factors (74-2984), satisfactory relative recoveries (94.5 ± 18.5-116.9 ± 12.5%), intraday precision (2.44-5.34%), inter-day precision (4.62-7.02%), low limit of detections (LODs, 0.10-0.29 ng L -1 ) and limit of quantifications (LOQs, 0.33-0.96 ng L -1 ) were achieved under the optimal conditions. This study provides an important idea in the rational design of porous organic polymers for solid-phase microextraction or other adsorption applications., (Copyright © 2017 Elsevier B.V. All rights reserved.)

This study presents the preparation and the characterizations of six tri-metal centered metal-organic frameworks (tM-MOFs) as solid-phase microextraction (SPME) adsorbents. Possessing different proportions of Al, Ga and In atoms in their frameworks, the tM-MOF-based SPME coatings exhibited different extraction performance towards the organic pollutants. Extraction results showed that the M4 (Al 0.593 Ga 0.167 In 0.240 (O 2 C 2 H 4 )(h 2 fipbb)) coating exhibited the best enrichment ability among six tM-MOFs. In addition, it showed better extraction efficiency towards the analytes than three single-metal centered MOFs coatings and a commercial polydimethylsiloxane (PDMS) coating. The adsorption process of the M4 coating was physical adsorption and it was mainly affected by the diffusion process of the compound from the sample to the material, which is the same with the adsorption processes of the single-metal centered MOFs coatings. Under optimal conditions (extraction time, 3 min; NaCl concentration, 25% (w/v); desorption temperature, 270 °C; extraction temperature, 30 °C), the M4 coating achieved low detection limits (0.13-0.88 ng L -1 ) and good linearity (5-2000 and 5-5000 ng L -1 ) for benzene series compounds. The repeatabilities (n = 5) for single fiber were between 4.3 and 8.1%, while the reproducibilities (n = 3) of fiber-to-fiber were in the range of 7.9-12.7%. Finally, a M4 coated SPME fiber was successfully applied to the analysis of environmental water samples with satisfactory recoveries (80.8%-119.5%)., (Copyright © 2017 Elsevier B.V. All rights reserved.)

In this contribution, it was discovered that even distribution of a metal-organic framework (MOF) [e.g. copper 1,4-benzenedicarboxylate (CBDC)] within polymeric matrixes (e.g. polyimide) resulted in a high-efficient coating material on the surface of a stainless steel wire (SSW). Consequently, a home-made solid phase microextraction (SPME) fiber was fabricated for fast determination of target analytes in real water samples. Scanning electron microscope images indicated that the coating possessed homogenously porous surface. Coupled with gas chromatography-mass spectrometry (GC-MS) and direct immersion SPME (DI-SPME) technique, the fiber was evaluated through the analysis of five polycyclic aromatic hydrocarbons (PAHs) in aqueous samples. Under optimized extraction and desorption conditions, the established method based on the home-made fiber exhibited good repeatability (4.2-12.7%, n = 6) and reproducibility (0.9-11.7%, n = 3), low limits of detection (LODs, 0.11-2.10 ng L -1 ), low limits of quantification (LOQs, 0.36-6.99 ng L -1 ) and wide linear ranges (20-5000 ng L -1 ). Eventually, the method was proven applicable in the determination of PAHs in real samples, as the recoveries were in a satisfactory range (81.7-116%)., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Graphene, a novel class of carbon nanostructures, has received great attention as sorbents due to its fascinating structures, ultrahigh specific surface area, and good extraction ability. In this paper, a new type of hierarchical graphene was synthesized through employing a mild and environment-friendly method. Such 3D interconnected graphene own a high specific surface area up to 524m(2)g(-1), which is about 2.5 fold larger than the graphene, since the synthetic material has interlayer pores between nanosheets and in-plane pores. Then a superior solid-phase microextraction fiber was fabricated by sequentially coating the stainless steel fiber with silicone sealant film and hierarchical graphene powder. Since the novel hierarchical graphene possessed large surface area and good adsorption property, the as-prepared fiber exhibited good extraction properties of the organochlorine pesticides (OCPs). As for the analytical performance, the as-prepared fiber achieved low detection limits (0.08-0.80ngL(-1)) and wide linearity (10-30,000ngL(-1)) under the optimal conditions. The repeatability (n=5) for single fiber were between 5.1% and 11%, while the reproducibility (n=3) of fiber-to-fiber were range from 6.2% to14%. Moreover, the fiber was successfully applied to the analysis of OCPs in the Pearl River water., (Copyright © 2016 Elsevier B.V. All rights reserved.)

A series of knitting aromatic polymers (KAPs) were successfully synthesized using a simple one-step Friedel-Crafts alkylation of aromatic monomers and were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Then, as-synthesized KAPs with large surface areas, unique pore structures and high thermal stability were prepared as solid-phase microextraction (SPME) coatings that exhibited good extraction abilities for a series of benzene compounds (i.e., benzene, toluene, ethylbenzene and m-xylene, which are referred to as BTEX) and polycyclic aromatic hydrocarbons (PAHs). Under the optimized conditions, the methodologies established for the determination of BTEX and PAHs using the KAPs-triPB and KAPs-B coatings, respectively, possessed wide linear ranges, low limits of detection (LODs, 0.10-1.13ngL(-1) for BTEX and 0.05-0.49ngL(-1) for PAHs) and good reproducibility. Finally, the proposed methods were successfully applied to the determination of BTEX and PAHs in environmental water samples, and satisfactory recoveries (93.6-124.2% for BTEX and 77.2-113.3% for PAHs) were achieved. This study provides a benchmark for exploiting novel microporous organic polymers (MOPs) for SPME applications., (Copyright © 2016 Elsevier B.V. All rights reserved.)

A combination of nitrogen-doped ordered mesoporous polymer (NOMP) and stainless steel wires led to highly sensitive, selective, and stable solid phase microextraction (SPME) fibers by in situ polymerization for the first time. The ordered structure of synthesized NOMP coating was illustrated by transmission electron microscopy (TEM) and X-ray diffraction (XRD), and microscopy analysis by scanning electron microscopy (SEM) confirmed a homogenous morphology of the NOMP-coated fiber. The NOMP-coated fiber was further applied for the extraction of organochlorine pesticides (OCPs) with direct-immersion solid-phase microextraction (DI-SPME) method followed by gas chromatography-mass spectrometry (GC-MS) quantification. Under the optimized conditions, low detection limits (0.023-0.77 ng L(-1)), a wide linear range (9-1500 ng L(-1)), good repeatability (3.5-8.1%, n=6) and excellent reproducibility (1.5-8.3%, n=3) were achieved. Moreover, the practical feasibility of the proposed method was evaluated by determining OCPs in environmental water samples with satisfactory recoveries., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Microporous organic polymers (MOPs) have emerged as a new class of functional porous materials with unique characteristics and potential uses in diverse areas. However, the field of MOPs for gas chromatographic (GC) separations has not been well explored. Herein, a MOP namely KAPs-1 was dynamic coated onto a capillary column for the first time. The fabricated column exhibited a nonpolar nature and the column efficiency for n-dodecane was up to 7769 plates m(-1). The KAPs-1 coated column showed high GC separation performance for a series of volatile organic compounds (VOCs) including the challenging ethylbenzene and xylene isomers, which could not be resolved at baseline on the commercial 5% phenyl polysiloxane stationary phase. Moreover, the relative standard deviations for five replicate determinations of the studied analytes were 0.0-0.6%, 0.9-3.2%, 1.1-5.9%, 0.8-3.7% for retention time, peak area, peak height and peak width, respectively. To investigate the interaction between some analytes and the stationary phase, thermodynamic and kinetic parameters were also evaluated. The results of this study show it is very promising to utilize MOPs as stationary phases for capillary GC., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Mesoporous TiO2 nanoparticles were synthesized with the hydrothermal method and characterized by powder X-ray diffraction (PXRD) and transmission electron microscope (TEM). Then a superior solid-phase microextraction (SPME) fiber was fabricated by sequentially coating the stainless steel fiber with silicone sealant film and mesoporous TiO2 powder. The developed fiber possessed a homogeneous surface and a long life-span up to 100 times at direct immersing (DI) extraction mode. Under the optimized conditions, the extraction efficiencies of the self-made 17 μm TiO2 fiber for six organochlorine pesticides (OCPs) were higher than those of the two commercial fibers (65 μm PDMS/DVB and 85 μm PA fibers) which were much thicker than the former. As for analytical performance, low detection limits (0.08-0.60 ng L(-1)) and wide linearity (5-5000 ng L(-1)) were achieved under the optimal conditions. The repeatabilities (n=5) for single fiber were between 2.8 and 12.3%, while the reproducibilities (n=3) of fiber-to-fiber were in the range of 3.7-15.7%. The proposed fiber was successfully applied to the sensitive analysis of OCPs in real water samples and four of the six analytes were detected from the rainwater and the lake water samples., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Metal-organic frameworks (MOFs) have received great attention as novel sorbents due to their fascinating structures and intriguing potential applications in various fields. In this work, a MIL-101(Cr)-coated solid-phase microextraction (SPME) fiber was fabricated by a simple direct coating method and applied to the determination of volatile compounds (BTEX, benzene, toluene, ethylbenzene, m-xylene and o-xylene) and semi-volatile compounds (PAHs, polycyclic aromatic hydrocarbons) from water samples. The extraction and desorption conditions of headspace SPME (HS-SPME) were optimized. Under the optimized conditions, the established methods exhibited excellent extraction performance. Good precision (<7.7%) and low detection limits (0.32-1.7 ng L(-1) and 0.12-2.1 ng L(-1) for BTEX and PAHs, respectively) were achieved. In addition, the MIL-101(Cr)-coated fiber possessed good thermal stability, and the fiber can be reused over 150 times. The fiber was successfully applied to the analysis of BTEX and PAHs in river water by coupling with gas chromatography-mass spectrometry (GC-MS). The analytes at low concentrations (1.7 and 10 ng L(-1)) were detected, and the recoveries obtained with the spiked river water samples were in the range of 80.0-113% and 84.8-106% for BTEX and PAHs, respectively, which demonstrated the applicability of the self-made fiber., (Copyright © 2014 Elsevier B.V. All rights reserved.)