A novel mutation in hERG gene associated with azithromycin-induced acquired long QT syndrome.

BACKGROUND: Mutations in human ether-à-go-go-related gene (hERG) potassium channels are closely associated with long QT syndrome (LQTS). Previous studies have demonstrated that macrolide antibiotics increase the risk of cardiovascular diseases. To date, the mechanisms underlying acquired LQTS remain elusive. METHODS: A novel hERG mutation I1025N was identified in an azithromycin-treated patient with acquired long QT syndrome via Sanger sequencing. The mutant I1025N plasmid was transfected into HEK-293 cells, which were subsequently incubated with azithromycin. The effect of azithromycin and mutant I1025N on the hERG channel was evaluated via western blot, immunofluorescence, and electrophysiology techniques. RESULTS: The protein expression of the mature hERG protein was down-regulated, whereas that of the immature hERG protein was up-regulated in mutant I1025N HEK-293 cells. Azithromycin administration resulted in a negative effect on the maturation of the hERG protein. Additionally, the I1025N mutation exerted an inhibitory effect on hERG channel current. Moreover, azithromycin inhibited hERG channel current in a concentration-dependent manner. The I1025N mutation and azithromycin synergistically decreased hERG channel expression and hERG current. However, the I1025N mutation and azithromycin did not alter channel gating dynamics. CONCLUSIONS: These findings suggest that hERG gene mutations might be involved in the genetic susceptibility mechanism underlying acquired LQTS induced by azithromycin.

Strategies for using magnetic beads in enhanced deep eutectic solvent-mechanochemical extraction of natural products from orange peels.

To address the challenges of low recovery, prolonged extraction times, and environmental pollution caused by toxic solvents in traditional extraction methods, magnetic bead-enhanced deep eutectic solvent mechanochemical extraction was developed for extracting natural products from orange peels. The extraction efficiencies of deep eutectic solvents were experimentally evaluated, and theoretical methods were used to guide solvent selection. Choline chloride-ethylene glycol demonstrated the highest efficiency under the optimal extraction conditions: a molar ratio of 1:2, no water content, a solid-liquid ratio of 0.08 g/mL, and an extraction time of 60 s. The synergy between the deep eutectic solvent and magnetic bead-enhanced the mechanochemical extraction efficiencies. The study also examined the effects of different magnetic bead types and orange peel powder particle sizes on extraction efficiency, finding that a 0.11 mm particle size combined with CIP@SiO2 yielded the best results. Overall, this study holds promise as an environmentally friendly and efficient extraction method.

Eco-friendly regeneration of lignin with acidic deep eutectic solvent for adsorption of pollutant dyes for water cleanup.

In this study, a simple and eco-friendly method was used to treat alkaline lignin with an acidic deep eutectic solvent (DES) to obtain regenerated lignin for the efficient adsorption of pollutant dyes from aqueous environment. Based on the yield and adsorption capacity of the sorbent for these dyes, conditions such as the type and concentration of DES component, solid-to-liquid ratio, reaction time, and temperature were optimized. By characterizing and comparing alkali lignin with regenerated lignin, a series of reactions were demonstrated to occur during the DES treatment process. The performance and mechanism of methylene blue and rhodamine B adsorption on regenerated lignin were studied systematically, and the maximum adsorbed amounts were 348.29 and 551.05 mg/g at 323 K, respectively. This study provides a new strategy for the green preparation of functionalized lignin and its use in the water pollutant treatment.

Preparation of carbon-rich material from Dendrobium officinale polysaccharide in deep eutectic system.

A carbon-rich material (DESysChar) was prepared from polysaccharide within a deep eutectic system (DESys) containing oxalic acid, and systematically characterized using various analytical techniques. The investigation of reaction mechanism revealed concurrent dehydration and etherification processes. This study commenced with the extraction of plant polysaccharide using the DESys-based mechanochemical extraction method from Dendrobium officinale. Subsequently, the DESys method was used to carbonize the extracted Dendrobium officinale polysaccharide and produce DESysChar. DESysChar was then used for the adsorption and determination of pollutants in water. This study represents a significant advancement in eco-friendly material synthesis, enabling the low-temperature (120 °C) carbonization of plant-derived polysaccharides, thereby reducing energy consumption and environmental impact. The effective adsorption of methylene blue by DESysChar underscores its potential in environmental remediation. This study presents a more responsible and efficient approach to polysaccharide extraction and carbonization, addressing environmental concerns. Embracing the 4S workflow (involving Sustainable raw materials converted into Sustainable degradable products, by using Sustainable technology throughout the process to create a Sustainable environment) promotes sustainability in material development, laying the foundation for future eco-friendly practices in various industries. In summary, this study propels sustainable polysaccharide development for widespread use.

[Synthesis of porous organic framework materials based on deep eutectic solvents and their application in solid-phase extraction].

This paper reviews the application of deep eutectic solvents (DESs) in the synthesis of metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) as well as their prospects in the field of solid-phase extraction (SPE). Porous organic frameworks (POFs) have unique properties such as a large specific surface area, high porosity, and easy modification. Thus, these materials are widely applied in the fields of catalysis, adsorption, drug delivery, gas storage, and separation. POFs include MOFs, COFs, conjugated microporous polymers (CMPs), porous aromatic frameworks (PAFs), and covalent triazine frameworks (CTFs). MOFs are constructed from metal ions/clusters and organic ligands through coordination bonds and can be extended in two or three dimensions by repeated coordination with potential voids. COFs are formed from two monomers containing light elements (such as carbon, hydrogen, oxygen, nitrogen, boron, and other elements) via coordination bonds and have large two- or three-dimensional structures. However, conventional POF synthesis methods generally suffer from disadvantages such as long synthesis times, high temperature and pressure requirements, and the use of toxic and hazardous reaction solvents. DES consists of a hydrogen bond acceptor (HBA) and a hydrogen bond donor (HBD) bound by hydrogen-bonding interactions. It is a promising green solvent for material synthesis owing to its low vapor pressure, high stability, and ease of preparation. DES can be used to prepare MOFs and COFs and, in specific cases, acts as a structure-directing agent, which has an important impact on the structure and properties of the resulting frameworks. Using appropriate DES formulations, researchers can modulate the crystal structures, pore sizes, and surface properties of MOFs and COFs, resulting in materials with excellent characteristics. SPE is an analytical technique in which a sample solution is added to an SPE column; the sample solution is forced through the stationary phase, and the target compounds are collected for analysis by elution with an organic solvent. Therefore, suitable stationary-phase materials are critical for SPE. Owing to their large specific surface areas and abundant active sites, MOFs and COFs exhibit outstanding adsorption capacity and selectivity in SPE and can effectively enrich target analytes from complex samples. DES-based MOFs and COFs have shown potential use in a wide range of applications, such as in environmental analysis, food testing, and biological sample analysis. Although DES-based MOFs and COFs for SPE are still in the early stages of development, their properties such as efficient enrichment and high selectivity offer good prospects for practical applications. Future research should continue to explore DES-based synthesis methods in depth to prepare other MOFs and COFs with the desired properties and investigate their potential applications in various fields. These efforts are expected to apply these novel materials in commercialized solid-phase extraction methods, bringing new development opportunities in the field of analytical chemistry.

Systolic Blood Pressure and Cardiovascular Risk in Normotensive Adults.

OBJECTIVE: To examine the association of systolic blood pressure (SBP) and cardiovascular risk in normotensive adults. PATIENTS AND METHODS: This study analyzed data from 7 prospective cohorts between September 29, 1948, and December 31, 2018. Complete information on history of hypertension and baseline blood pressure measurements were required for inclusion. We excluded individuals younger than 18 years old, those with a history of hypertension, and patients with baseline SBP measurements of less than 90 mm Hg or 140 mm Hg or higher. Cox proportional hazards regression and restricted cubic spline models were used to evaluate the hazards of cardiovascular outcomes. RESULTS: A total of 31,033 participants were included. The mean ± SD age was 45.3±14.8 years, 16,693 of the participants (53.8%) were female, and the mean ± SD SBP was 115.8±11.7. Over a median follow-up of 23.5 years, 7005 cardiovascular events occurred. Compared with those who had SBP levels of 90 to 99 mm Hg, participants with SBP levels of 100 to 109, 110 to 119, 120 to 129, and 130 to 139 mm Hg experienced 23% (hazard ratio [HR], 1.23; 95% CI, 1.07 to 1.42), 53% (HR, 1.53; 95% CI, 1.33 to 1.76), 87% (HR, 1.87; 95% CI, 1.62 to 2.16), and 117% (HR, 2.17; 95% CI, 1.87 to 2.52) increased risks of cardiovascular events, respectively. Compared with follow-up SBP of 90 to 99 mm Hg, the HRs for cardiovascular events were 1.25 (95% CI, 1.02 to 1.54), 1.93 (95% CI, 1.58 to 2.34), 2.55 (95% CI, 2.09 to 3.10), and 3.39 (95% CI, 2.78 to 4.14), respectively, for follow-up SBP levels of 100 to 109, 110 to 119, 120 to 129, and 130 to 139 mm Hg. CONCLUSION: In adults without hypertension, there is a stepwise increase in risk of cardiovascular events, with increasing SBP starting at levels as low as 90 mm Hg.

Administration of macrolide antibiotics increases cardiovascular risk.

Background: The increased risk of cardiovascular events in patients prescribed macrolides has been subject to debate for decades. Methods: Medline, EMBASE databases and ClinicalTrials.gov were searched from inception until August 31, 2022 for studies investigating the link between macrolides and cardiovascular risk. A meta-analysis was performed using a random-effects model. Results: A total of 80 studies involving 39,374,874 patients were included. No association was found between macrolides and all-cause death. However, compared with the non-macrolide group, macrolides were associated with a significantly increased risk of ventricular arrhythmia or sudden cardiac death (VA or SCD) (azithromycin, relative ratio [RR]: 1.53; 95% confidence interval [CI]: 1.19 to 1.97; clarithromycin, RR: 1.52; 95% CI: 1.07 to 2.16). Besides, administration of macrolides was associated with a higher risk of cardiovascular disease (CVD) death (azithromycin, RR: 1.63; 95% CI: 1.17 to 2.27) and a slightly increased risk of myocardial infarction (MI) (azithromycin, RR: 1.08; 95% CI: 1.02 to 1.15). Interestingly, no association was observed between roxithromycin and adverse cardiac outcomes. Increased risk of VA or SCD was observed for recent or current use of macrolides, MI for former use, and CVD death for current use. Conclusion: Administration of macrolide antibiotics and timing of macrolide use are associated with increased risk for SCD or VTA and cardiovascular death, but not all-cause death.

Ionic liquid as hydrogen bond acceptor in the extraction of nutritional natural products.

In-depth studies of the extraction mechanism using deep eutectic solvents (DES), especially extraction through the formation of a deep eutectic system (DESys), revealed commonalities between the DES- and ionic liquids (IL)-based extraction systems. New applications of ILs and DES for extraction of nutritional natural products were presented. In this study, the extraction behavior of choline chloride (ChCl) and 1-(2-hydroxyethyl)-3-methylimidazolium chloride ([HMIm][Cl]) in DES and IL, respectively, in mechanochemical extraction of target compounds from Moringa oleifera leaves was systematically studied. The results suggested that both extraction methods were based on the formation of a DESys, either a normal DESys or an IL DESys. Considering the DESys-based one-step extraction improves the extraction efficiency and reduces the preparation time, the same idea can be used in IL for performance improvement. By formation of a new IL deep eutectic system based on hydrogen bond interaction in extraction, similar improvement was obtained.

Influence of host-guest interactions on analytical performance of direct analysis in real-time mass spectrometry.

To systematically study the influence of host-guest interactions on the analytical performance of direct analysis in real time mass spectrometry (DART-MS), the interactions between cyclodextrins (CDs) and different Sudan dyes were investigated. The results showed that the host-guest interaction between CDs and Sudan dyes did not affect qualitative analysis of the target compounds, but led to a lower signal intensity for Sudan dyes, thus affecting quantitative analysis of the target compounds. The stronger the host-guest interaction, the weaker the signal intensity of target compound on DART-MS. The results also show that both in solution and in solid-phase microextraction (SPME), the addition of organic solvents can weaken the host-guest interaction between CDs and Sudan dyes, thus improving the signal intensity in DART-MS. In SPME, adding organic solvents has a certain practical value and can improve the efficiency of Sudan dye analysis. This study suggests that appropriate sample pretreatment is needed to weaken noncovalent interactions prior to DART-MS analysis to obtain more accurate quantitative results. The data provide some insight into the effects of other noncovalent interactions on the efficiency of DART-MS as an analytical tool, as well as the potential to study intermolecular interactions with DART-MS.

Plant polysaccharide itself as hydrogen bond donor in a deep eutectic system-based mechanochemical extraction method.

A deep eutectic system (DESys) is formed when a hydrogen bond acceptor (HBA) is processed with polysaccharide (hydrogen bond donor, HBD) containing plant substance in water to dissolve, extract, and recover the polysaccharide directly, instead of using a traditional deep eutectic solvent (DES). The extraction efficiency is enhanced by the direct formation of the DESys, in a mechanochemical extraction (MCE) system. Key factors affecting the extraction efficiency were systematically studied and optimized. The effects of the DESys on the structure and physicochemical properties of polysaccharides were studied by several analytical techniques. The findings demonstrated that the direct DESys formation extraction efficiency was superior than that of traditional extraction methods while retaining physicochemical properties of polysaccharides. Moreover, the composition of polysaccharides extracted with this method is different from that obtained by conventional methods. The recovery and purification process of polysaccharides is simplified by eliminating the need for an additional HBD.

Dynamic Change of Cardiovascular Health Metrics and Long-Term Risk of Sudden Cardiac Death: The ARIC Study.

Background The change of cardiovascular health (CVH) status has been associated with risk of cardiovascular disease. However, no studies have explored the change patterns of CVH in relation to risk of sudden cardiac death (SCD). We aim to examine the link between baseline CVH and change of CVH over time with the risk of SCD. Methods and Results Analyses were conducted in the prospective cohort ARIC (Atherosclerosis Risk in Communities) study, started in 1987 to 1989. ARIC enrolled 15 792 individuals 45 to 64 years of age from 4 US communities (Forsyth County, North Carolina; Jackson, Mississippi; suburbs of Minneapolis, Minnesota; and Washington County, Maryland). Subjects with 0 to 2, 3 to 4, and 5 to 7 ideal metrics of CVH were categorized as having poor, intermediate, or ideal CVH, respectively. Change in CVH over 6 years between 1987 to 1989 and 1993 to 1995 was considered. The primary study outcome was physician adjudicated SCD. The study population consisted of 15 026 subjects, of whom 12 207 had data about CVH change. Over a median follow-up of 23.0 years, 583 cases of SCD were recorded. There was a strong inverse association between baseline CVH metrics and time varying CVH metrics with risk of SCD. Compared with subjects with consistently poor CVH, risk of SCD was lower in those changed from poor to intermediate/ideal (hazard ratio [HR], 0.67 [95% CI, 0.48-0.94]), intermediate to poor (HR, 0.73 [95% CI, 0.54-0.99]), intermediate to ideal (HR, 0.49 [95% CI, 0.24-0.99]), ideal to poor/intermediate CVH (HR, 0.23 [95% CI, 0.10-0.52]), or those with consistently intermediate (HR, 0.49 [95% CI, 0.36-0.66]) or consistently ideal CVH (HR, 0.31 [95% CI, 0.13-0.76]). Similar results were also observed for non-SCD. Conclusions Compared with consistently poor CVH, other patterns of change in CVH were associated with lower risk of SCD. These findings highlight the importance of promotion of ideal CVH in the primordial prevention of SCD.

Association Between Temporal Changes in Early Repolarization Pattern With Long-Term Cardiovascular Outcome: A Population-Based Cohort Study.

Background The prognostic value of early repolarization pattern (ERP) remains controversial. We aim to test the hypothesis that temporal changes in ERP are associated with increased risks for sudden cardiac death (SCD) and cardiovascular death. Methods and Results A total of 14 679 middle-aged participants from the prospective, population-based cohort were included in this analysis, with ERP status recorded at baseline and during 3 follow-up visits in the ARIC (Atherosclerosis Risk in Communities) study. We related baseline ERP, time-varying ERP, and temporal changes in ERP to cardiovascular outcomes. Cox models were used to estimate the hazard ratios (HRs) adjusted for possible confounding factors. With a median follow-up of 22.5 years, there were 5033 deaths, 1239 cardiovascular deaths, and 571 SCDs. Time-varying ERP was associated with increased risks of SCD (HR, 1.59 [95% CI, 1.25-2.02]), cardiovascular death (HR, 1.70 [95% CI, 1.44-2.00]), and death from any cause (HR, 1.16 [95% CI, 1.05-1.27]). Baseline ERP was also associated with 3 outcomes. Compared with those with consistently normal ECG findings, subjects with new-onset ERP or consistent ERP experienced increased risks of developing SCD and cardiovascular death. The time-varying ERP in women, White subjects, and anterior leads and J-wave amplitudes ≥0.2 mV appeared to indicate poorer cardiovascular outcomes. Conclusions Our findings suggest that baseline ERP, time-varying ERP, new-onset ERP, and consistent ERP were independent predictors of SCD and cardiovascular death in the middle-aged biracial population. Repeated measurements of the ERP might improve its use as a risk indicator for SCD.

Longitudinal change in lung function and subsequent risks of cardiovascular events: evidence from four prospective cohort studies.

BACKGROUND: Lung function is constantly changing over the life course. Although the relation of cross-sectional lung function measure and adverse outcomes has been reported, data on longitudinal change and subsequent cardiovascular (CV) events risks are scarce. Therefore, this study is to determine the association of longitudinal change in lung function and subsequent cardiovascular risks. METHODS: This study analyzed the data from four prospective cohorts. Subjects with at least two lung function tests were included. We calculated the rate of forced respiratory volume in 1 s (FEV1) and forced vital capacity (FVC) decline for each subject and categorized them into quartiles. The primary outcome was CV events, defined as a composite of coronary heart disease (CHD), chronic heart failure (CHF), stroke, and any CV death. Cox proportional hazards regression and restricted cubic spline models were applied. RESULTS: The final sample comprised 12,899 participants (mean age 48.58 years; 43.61% male). Following an average of 14.79 (10.69) years, 3950 CV events occurred. Compared with the highest FEV1 quartile (Q4), the multivariable HRs for the lowest (Q1), 2nd (Q2), and 3rd quartiles (Q3) were 1.33 (95%CI 1.19, 1.49), 1.30 (1.16, 1.46), and 1.07 (0.95, 1.21), respectively. Likewise, compared with the reference quartile (Q4), the group that experienced a faster decline in FVC had higher HRs for CV events (1.06 [95%CI 0.94-1.20] for Q3, 1.15 [1.02-1.30] for Q2, and 1.28 [1.14-1.44] for Q1). The association remained robust across a series of sensitivity analyses and nearly all subgroups but was more evident in subjects < 60 years. CONCLUSIONS: We observed a monotonic increase in risks of CV events with a faster decline in FEV1 and FVC. These findings emphasize the value of periodic evaluation of lung function and open new opportunities for disease prevention.

Grain Growth of MAPbI3 via Diethylammonium Bromide Induced Grain Mergence.

Various additives are used to improve the film morphology, crystal quality, and grain size for the sake of enhancing the performance of three-dimensional perovskite solar cells. Although significant enhancement in the performance of devices has been made due to the introduction of additives, an in-depth understanding of the additive-related crystallization kinetics and the growth mechanism is still lacking. Here, the grain growth mechanism of diethylammonium bromide (DABr)-doped MAPbI3 is investigated using in situ dynamic microscopy techniques. The results reveal that the alkyl chains of DABr restrain the growth of grains of MAPbI3 during spin-coating, and DABr-induced grain mergence during the annealing process, achieving large grains on the micrometer scale. Meanwhile, the crystallization of MAPbI3 with DABr is significantly improved and the number of defects is reduced. The solar cell with optimized DABr doping MAPbI3 as the active layer presents a higher power conversion efficiency (PCE) of 19.58% with a fill factor of 79.81%.

Impacts of carrier trapping and ion migration on charge transport of perovskite solar cells with TiO x electron transport layer.

The ion migration in perovskite materials has been extensively studied by researchers, but the charge dynamic distribution caused by ion migration and carrier trapping is partly unclear. To investigate the impacts of ion migration and defect induced carrier trapping on the carrier transport and the carrier collection, we measured the evolution of the photocurrent response in microseconds, milliseconds and seconds for the perovskite solar cells pretreated at different biases. Our results reveal that the photocurrent of the solar cells pretreated at negative bias decreases with time and achieves its minimum at several milliseconds, then rises and achieves its maximum at tens of seconds. For the device pretreated at positive bias beyond built-in potential, the time to reach maximum photocurrent is much shorter than that of the solar cell pretreated at negative bias. The transient photocurrent responses to the sequence of single-light-pulses also show that there is obvious carrier trapping in a positive bias treated device, which indicates that defect induced carrier trapping is the critical factor for the perovskite solar cells with an n-TiO x electron transport layer. In order to improve the performance of the perovskite solar cells with nano-TiO x ETL, it is very necessary to significantly reduce defects. Our results also demonstrate that cation accumulation at the interface between the perovskite active layer and ETL can enhance the device performance to a certain extent.

Sorbent and solvent co-enhanced direct analysis in real time-mass spectrometry for high-throughput determination of trace pollutants in water.

A sorbent and solvent co-enhanced direct analysis in real-time mass spectrometry (SSE-DART-MS) method was developed for high-throughput determination of trace pollutants in water. The use of sorbent for preconcentration and solvents for assisting desorption and ionization synergistically enhanced the signals from the trace pollutants detected by DART-MS. Phthalic acid esters (PAEs) were used as model analytes to validate the SSE-DART-MS method. Graphitic carbon nitride (g-C3N4)-based materials with two morphologies and six organic solvents were used to systematically evaluate the enhancement effect by the sorbent and solvent. A better analytical performance was achieved with the two-dimensional (2D) g-C3N4, compared to three-dimensional (3D) g-C3N4/C, indicating that the morphologies of sorbents played a key role in SSE-DART-MS analysis. The MS signals of all the analytes were increased by 10-100 times for the two materials in the presence of the selected solvents. With the SSE-DART-MS method, concentration limits of detection for water samples in the range 0.07-0.94 ng L-1, and recovery in the range 82.8-119% using g-C3N4, were obtained for the PAEs. This work not only provides a reliable method for the coupling of solid phase extraction technique with DART-MS, but also presents valuable information for conducting other DART-MS analyses.

Efficient Quasi-Two-Dimensional Perovskite Light-Emitting Diodes with Improved Multiple Quantum Well Structure.

Quasi-two-dimensional (quasi-2D) perovskites with a multiple quantum well structure can enhance the exciton binding energy and controllable quantum confine effect, which are attractive materials for efficient perovskite light-emitting diodes (PeLEDs). However, the multiphase mixtures contained in these materials would cause nonradiative recombination at the perovskite film surface. Here, a facile solution surface treatment is adopted to improve the multiple quantum well structure of the quasi-2D perovskite emitting layer, which can reduce the influence of defectinduced nonradiative recombination and the electric-field-induced dissociation of excitons for the PeLEDs. The improved multiple quantum well structure is verified by UV absorption spectra and temperature-dependent photoluminescence spectra measurements. The photoluminescence quantum yield of the quasi-2D perovskite film with surface treatment has been approximately increased by 200%. Meanwhile, the electroluminescence device achieves a current efficiency of 45.9 cd/A.

Dispersive Magnetic Solid-Phase Extraction Coupled to Direct Analysis in Real Time Mass Spectrometry for High-Throughput Analysis of Trace Environmental Contaminants.

Coupling dispersive magnetic solid-phase extraction (DMSPE) to direct analysis in real time mass spectrometry (DART-MS) with a newly developed metal iron probe enables high-throughput, sensitive detection of herbicides such as triazine in environmental waters. Magnetic graphene oxide was used as a dispersive sorbent because it increased adsorption capacity in the DMSPE process. The planar structure and excellent thermal conductivity of graphene oxide facilitated the desorption and ionization of target analytes in DART-MS analysis. The iron probe, which is designed to fit into the moving trail of the DART interface, served as the sorbent collector as well as the support for the magnetic graphene oxide after DMSPE, and was put directly into the DART system. The ratio of magnetic core to graphene oxide in the nanoparticles and other key parameters in DMSPE and DART-MS procedures were systematically investigated and optimized. In addition, the presence of water on the sorbent proves to have a significant effect on DART-MS analysis. No organic solvents are used in this method, and the reusable iron probe is of low cost. Under the optimal conditions, limits of detection were found in the range of 1.6-152.1 ng/L for the triazines. Recovery and reproducibility were found to be in the ranges of 87.5-115.0% and 1.9-10.2%, respectively, for the six herbicides studied. The analytical performance of the DMSPE-DART-MS method indicated that applications for trace analysis of other compounds in liquid samples are also possible.

Solvent-free high-throughput analysis of herbicides in environmental water.

A high throughput, and eco-friendly method based on solid-phase microextraction (SPME) combined with direct analysis in real time mass spectrometry (DART-MS) was established for the determination of trace pollutants in water. A laboratory-made SPME device coated with a metal organic framework (MIL-100 (M)) was fabricated for the on-site enrichment of triazine herbicides in environmental water, and the device was directly subjected to DART ionization (<20 s) for high resolution MS. The interactions between the target analytes and sorbents were investigated to improve the SPME device targeting specific pollutants, as well as to improve the desorption and ionization processes with DART-MS. Other factors were also systematically studied to obtain the optimal conditions, including pH, salinity, extraction temperature, pressure at the Vapur® interface, linear rail moving speed, gas temperature, extraction time, and sample volume. The limit of detection of target compounds were 5.0-50.0 ng L-1 and the recoveries ranged from of 92.4%-125.7%.

Magnetic nanoparticles speed up mechanochemical solid phase extraction with enhanced enrichment capability for organochlorines in plants.

A mechanochemical magnetic solid phase extraction (MCMSPE) method was developed for a one-pot extraction and enrichment of organochlorine pesticides in tea leaves to demonstrate the advantage of using magnetic nanoparticles in the sample preparation process. The enriched analytes were subsequently detected by ultra-high performance liquid chromatography and gas chromatography mass spectrometry. The presence of magnetic metal-organic-framework (MMOF) (Fe3O4@MIL-100 (Fe)) nanoparticles help to rupture the cell walls in solid plant samples more thoroughly, and at the same time, act as a selective sorbent for the enrichment of target analytes. Compared to traditional methods, this approach significantly shortens the sample processing time from tens of minutes to tens of seconds. The parameters of the procedure were systematically studied and optimized to achieve good limits of detection (0.62-3.92 ng g-1, LOD S/N = 3), significantly improved recoveries (81.46-113.59%), and good reproducibility (RSD 2.63-9.87%, n = 5). The results indicated that this method can be applied for high throughput determination of organochlorine pesticides in tea leaves, and can be used for other dried plant samples.