The role of ferroptosis in acute kidney injury: mechanisms and potential therapeutic targets.

Acute kidney injury (AKI) is one of the most common and severe clinical renal syndromes with high morbidity and mortality. Ferroptosis is a form of programmed cell death (PCD), is characterized by iron overload, reactive oxygen species accumulation, and lipid peroxidation. As ferroptosis has been increasingly studied in recent years, it is closely associated with the pathophysiological process of AKI and provides a target for the treatment of AKI. This review offers a comprehensive overview of the regulatory mechanisms of ferroptosis, summarizes its role in various AKI models, and explores its interaction with other forms of cell death, it also presents research on ferroptosis in AKI progression to other diseases. Additionally, the review highlights methods for detecting and assessing AKI through the lens of ferroptosis and describes potential inhibitors of ferroptosis for AKI treatment. Finally, the review presents a perspective on the future of clinical AKI treatment, aiming to stimulate further research on ferroptosis in AKI.

Oxolinic Acid Generated Green Fluorescence Based on a Terbium-Functionalized Covalent Organic Framework.

Oxolinic acid (OXO), a classic environmental contaminant, has a terrible detrimental effect on human health. The exploration of efficient strategies to detect and detecting OXO has remarkable significance. Herein, we reported a novel terbium(III)-functionalized covalent organic framework (Bpy-DhBt-COF@Tb3+) by fixing Tb3+ on the bipyridine-connecting COF (Bpy-DhBt-COF) as a turn-on fluorescent switch toward OXO for the first time. In this platform, Tb3+ acts as the specific recognition units for OXO and the response signal, while Bpy-DhBt-COF acts as the safehaven for Tb3+. Once introducing OXO to Bpy-DhBt-COF@Tb3+, OXO can instead water molecules coordinate with Tb3+ and sensitize Tb3+ instantly, thereby producing a significant fluorescence signal. Profiting from the excellent porosity of Bpy-DhBt-COF@Tb3+, it can obtain optimal response toward OXO only within 10 s with an ultrasensitive detection limit of 12.5 nM. Furthermore, Bpy-DhBt-COF@Tb3+ displayed outstanding selectivity toward OXO than other general quinolones. Based on these, a Tb3+-based COF was explored for the first time for the turn-on fluorescence detection of an OXO with rapid response, high sensitivity, and outstanding selectivity. In this work, we not only exhibit the attractive performance of Tb3+-functionalized COF to detect OXO but also propose a prospect strategy for creating other fluorescent sensors for multiple targets.

Long noncoding RNA LINC00921 serves as a predictive biomarker for lung adenocarcinoma: An observational study.

Lung adenocarcinoma (LUAD) is usually diagnosed at advanced stages. Hence, there is an urgent need to seek an effective biomarker to predict LUAD status. Long noncoding RNAs (lncRNAs) play key roles in the development of tumors. However, the relationship between LINC00921 and LUAD remains unclear. The gene expression data of LUAD were downloaded from the Cancer Genome Atlas database to investigate the expression level of LINC00921 in LUAD. Diagnostic ability analysis, survival analysis, tumor mutational burden analysis, and immune cell infiltration analysis of LINC00921 in LUAD patients were performed simultaneously. According to the median expression value of LINC00921, patients were divided into LINC00921 high- and low-expression groups. The function of LINC00921 in LUAD was identified through difference analysis and enrichment analysis. Moreover, drugs that may be relevant to LUAD treatment were screened. Finally, blood samples were collected for real-time polymerase chain reaction. LINC00921 was significantly lower in LUAD tumor tissues. Notably, patients with low expression of LINC00921 had a shorter median survival time. Decreased immune cell infiltration in the tumor microenvironment in the low LINC00921 expression group may contribute to poorer patient outcomes. Tumor mutational burden was significantly different in survival between the LINC00921 high- and low-expression groups. In addition, LINC00921 may exert an influence on cancer development through its regulation of target genes transcription. Glyceraldehyde-3-phosphate dehydrogenase-related drugs may be more likely to be therapeutically effective in LUAD. LINC00921 was able to be used as the potential diagnostic indicator for LUAD.

Composite Foams of the Graphitic Carbon Nitride@Carbon Nanofibrils Conferred a Superamphiphilic Property and Reinforced Thermal Stability.

Herein, we demonstrated the preparation of novel three-dimensional (3D) superamphiphilic g-C3N4@carbon nanofibers foam (g-C3N4@CNFs) via a two-step approach: liquid nitrogen treatment-freeze-drying; the foams possessed good thermal stability. In this approach, melamine acted as a nitrogen source, and nanofibrillated cellulose (NFCs) functioned as a 3D skeleton. The thermal stability of the as-prepared g-C3N4@CNFs-3 foam was much higher than that of g-C3N4@CNFs-1, as indicated by thermogravimetric data, including an increase of the onset weight loss point (Tonset) by 238.6 °C and an improvement of the maximal weight loss rate (Tmax) by 258.8 °C. The combination of g-C3N4 with CNFs conferred a reduction in the heat release rate (ca. -86%) and the total heat release (ca. -75%). Furthermore, the composition of the hydrophilically oxygenated functional groups and hydrophobic triazine domains in g-C3N4@CNFs rendered it a unique amphiphilic property (contact angle close to 0° within 1.0 s for water and 0° within 12 ms for hexane). A high storage capacity for water and various organic solvents of the superamphiphilic g-C3N4@CNFs foam was found, up to 40-50 times its original weight. The discovery of these superamphiphilic foams is of great significance for the development of superwetting materials and may find their applications in oil emulsion purification and catalyst support fields.

Analysis of future nitrogen and phosphorus loading in watershed and the risk of lake blooms under the influence of complex factors: Implications for management.

For the management of eutrophic lakes, watershed nitrogen and phosphorus control is oriented to future water quality. Assessing future nutrient dynamics and the risk of lake eutrophication is necessary. However, current assessments often lack integrated consideration of socioeconomic and climatic factors, which reduces the reference value of the results. In this study, a typical large shallow lake Chaohu, which is highly influenced by human activities, was selected as the study area, and the current and future total nitrogen (TN) and total phosphorus (TP) loading in the basin were analysed using the improved MARINA model, and the risk of water bloom were assessed. The results showed that socioeconomic factors alone varied future TN and TP loading by -24% to 32% and -40% to 34%, respectively, under different development patterns. After considering the effect of increased precipitation, the changes of TN and TP loading became -10% to 163% and -29% to 108%, respectively. The effect on loading reduction under the sustainable development pattern was weakened (58% and 28% for TN and TP loading, respectively) and the increase in loading under the brutal development pattern was significantly amplified (409% and 215% for TN and TP loading, respectively). The adoption of active environmental policies remained an effective way of loading control. However, the risk of water bloom in local lake areas might persist due to factors such as urbanization. Timely and comprehensive assessments can provide managers with more information to identify key factors that contribute to the risk of water blooms and to develop diverse water quality improvement measures. The insights from our study are applicable to other watersheds around the world with similar socio-economic background and climatic conditions.

Acupuncture for cancer pain: a scoping review of systematic reviews and meta-analyses.

Background: Due to the effectiveness and safety, acupuncture, one of the traditional therapies of Chinese medicine, has been widely used in clinical practice globally. A few systematic review or meta-analyses have proved its effectiveness and safety towards patients with cancer pain, while there are no syntheses among those evidence. The aim of this scoping review is to summarize the evidence from systematic reviews of acupuncture for the treatment of cancer pain and evaluate the breadth and methodological quality of these evidence as well. Methods: The scoping review process was guided by the methodology framework of Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews (PRISMA ScR) and "Arkseyand O'Malley six-stage framework". Electronic searches were carried out in several online databases from inception to Jan 2022. Systematic reviews and meta-analyses that involve any type of acupuncture for patients with cancer pain will be included. A pair of reviewers independently screened full texts. Moreover, review characteristics were extracted, and methodological quality was assessed using the AMSTAR 2 tool. Results: Twenty-five systematic reviews and meta-analyses were included. Manual acupuncture is the most frequently included types of test group intervention (48%), followed by acupuncture + medicine (28%), and auricular acupuncture (12%). All the reviews have declared that acupuncture is an effective method for cancer pain treatment. Eleven reviews (44%) aiming at evaluating the safety also have confirmed that acupuncture is safe for treating cancer pain. However, most included studies were conducted in China. With certain geographical limitations, the findings were not representative within the region. The results of our review may owe to the synthesis of all kinds of cancer pain, and only 2 reviews described the type of cancer pain in detail. Conclusions: This scoping review synthesizes and evaluates existing evidence of acupuncture for cancer pain. From this scoping review of systematic reviews and meta-analyses, there are clear recommendations for future studies: expanding the region of research in the world and trying to conduct the study of different types of cancer pain in details as much as possible. Evidences of acupuncture for cancer pain can inform clinical decision-making. Systematic review registration: https://inplasy.com/inplasy-2022-1-0073/, identifier INPLASY202210073.

Radical radiotherapy for cervical cancer and meningioma with a history of Guillain-Barré syndrome: A case report.

RATIONALE: Guillain-Barré syndrome (GBS) is a rare autoimmune disease. Patients with cervical malignancies and intracranial meningiomas after the course of GBS are even rarer. There are no relevant reports at present. PATIENT CONCERNS: We report a patient who developed cervical cancer (CC) and intracranial meningioma simultaneously after the course of GBS. DIAGNOSES: The history, pelvic enhanced magnetic resonance imaging (MRI) and pathology confirmed cervical squamous cell carcinoma, and the head enhanced MRI confirmed meningioma. INTERVENTION: After multi-disciplinary team, the patient received head stereotactic radiosurgery for meningioma and radical radiotherapy for CC. OUTCOMES: The follow up for 1 year after treatment revealed a complete remission of the cervical tumor, stable disease of the meningioma, and no signs of GBS recurrence. Up to now, the general condition of the patient is acceptable and the curative effect is satisfactory. LESSONS: This case report aims to improve the oncologists' understanding of malignant tumors with rare autoimmune diseases and provide treatment reference for similar diseases in the future.

Design of terbium (III)-functionalized covalent organic framework as a selective and sensitive turn-on fluorescent switch for ochratoxin A monitoring.

For the first time, we develop a terbium (III)-functionalized covalent organic framework named Dpy-NhBt-COF@Tb3+, through anchoring Tb3+ onto a two-dimensional imine COF (Dpy-NhBt-COF), as the selective and sensitive turn-on fluorescent switch for ochratoxin A (OTA) monitoring. Of particular significance, Tb3+ actually plays two roles during sensing process: the specific response signal, and exclusive recognition sites for OTA, while Dpy-NhBt-COF acts as the protector for Tb3+. The sensing process involves the replacement of coordinated water molecules from Tb3+ by OTA and the energy transfer from OTA to Tb3+ centers, resulting in remarkable fluorescence emergence of Tb3+. The stabilization of Tb3+ via coordination with bipyridine of Dpy-NhBt-COF not only reduces the nonselective binding of naturally occurring ligands, but also avoids the non-radiative quenching caused by solvents molecules. As a sensing platform, Dpy-NhBt-COF@Tb3+ possesses noticeable selectivity and high sensitivity toward OTA with an ultralow detection limit of 13.5 nM and rapid response of 10 s. Taken together, our work not only demonstrates great prospect of Tb3+-functionalized COF for OTA detection, but also provides a potential way to explore other functionalized materials as promising sensors for other targets.

Click reaction triggered turn-on fluorescence strategy for highly sensitive and selective determination of steroid hormones in food samples.

The copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) click reaction has becoming noticeable in the field of analytical chemistry. Mild reaction conditions, simple operation, high efficiency, and good regioselectivity make this classical click reaction a perfect strategy for chemical derivatization. Herein, we proposed a promising click fluorescent labeling method with high selectivity for the determination of five steroid hormones in food samples. The labeling strategy depends on the reaction between 3-Azido-7-hydroxycoumarin and the alkynyl group of steroid hormones, which shows a turn-on fluorescence response in the presence of copper (I). The formed fluorescent products were detected by HPLC-FLD. Under the optimized conditions, the proposed method presented excellent performance with good linearity (R2 ≥ 0.9998) and low detection limit (1.8-7.3 µg L-1). Further, satisfactory recoveries were obtained to be 82-107% in spiked meats with relative standard deviations (RSDs) ≤ 5.7%. Finally, the established method was successfully applied for the determination of steroid hormones in meat, indicating the potential prospect of the click reaction in chemical derivatization.

Risk of dietary intake of organochlorine pesticides among the childbearing-age women: A multiple follow-up study in North China.

Exposure to organochlorine pesticides (OCPs) can cause adverse health effects in the female population. We investigated the dietary OCP intake of childbearing-age women living in large agricultural areas of Northern China, as well as their associated health risks. Ten childbearing-age women were recruited during 2015-2016. Their weekly dietary intake diaries and food samples were collected over the course of five visits. The OCP residues of 322 food samples from seven categories (i.e., cereal, vegetable, fruit, fish, meat, egg, and milk) were analyzed by gas chromatography-mass spectrometry. The average concentrations of the total hexachlorocyclohexanes (ΣHCH), dichlorodiphenyltrichloroethanes and their metabolites (ΣDDX), endosulfans (ΣES), and dieldrin and endrin (ΣDrin) in all food categories were, overall, much lower than the maximum residue limits. Relative high mean residues of ΣDrin and ΣES were found in fruits (ΣDrin: 0.687 ng g-1 wet weight (w.w.), ΣES: 2.24 ng g-1 w.w.) and vegetables (ΣDrin: 0.690 ng g-1 w.w., ΣES: 2.11 ng g-1 w.w.). The estimated daily dietary intake (EDI) of these compounds was calculated, with mean levels of 10.6 (ΣES) > 4.37 (ΣDrin) > 1.51 (ΣHCH) > 0.850 (ΣDDX) ng kg-1 day-1. Women during the heating period (from January to March) tended to ingest more ΣHCH, ΣDDX, ΣDrin, and ΣES. Overall, women had no obvious non-carcinogenic and carcinogenic risks due to intake of OCPs, but 83.9% of them has potential carcinogenic risk, with estimated life carcinogenic risk (LCR) exceeding 10-6. Furthermore, women had a higher potential carcinogenic risk during the heating period (mean LCR: 1.33 × 10-5) than during the non-heating period (mean LCR: 8.50 × 10-6). ΣDrin was the dominant OCP responsible for health risks, followed by ΣHCH. We concluded that women in North China still have some dietary OCP intake, especially during the heating period.

Associations of Dietary Exposure to Organochlorine Pesticides from Plant-Origin Foods with Lipid Metabolism and Inflammation in Women: A Multiple Follow-up Study in North China.

This study explored effects of dietary OCP intake from plant-origin foods (cereals, fruits, and vegetables) consumption on lipid metabolism and inflammation of women using a multiple follow-up study. The results showed that dietary intake of p,p'-dichlorodiphenyltrichloroethane (DDT) [ß = - 10.11, 95% confidence interval (95%CI): - 17.32, - 2.905] and o,p'-dichlorodiphenyldichloroethylene (DDE) (ß = - 6.077, 95%CI: - 9.954, - 2.200) were overall negatively associated with serum high-density lipoprotein cholesterol (HDL), whereas other OCPs were not. Serum interleukin (IL)-8 was positively associated with intake of dieldrin (ß = 0.390, 95%CI: 0.105, 0.674), endosulfan-ß (ß = 0.361, 95%CI: 0.198, 0.523), total endosulfan (ß = 0.136, 95%CI: 0.037, 0.234), and total OCPs (ß = 0.084, 95%CI: 0.016, 0.153), and negatively correlated with intake of p,p'-DDE (ß = - 2.692, 95%CI: - 5.185, - 0.198). We concluded that dietary intake of some individual DDT-, DDE- dieldrin-, and endosulfan-class chemicals from plant-origin foods may interfere with lipid metabolism and inflammation responses.

Distribution of mercury in serum and blood cells and risk of spontaneous preterm birth: A nested case-control study in China.

The relationship between maternal mercury (Hg) intake and the risk of spontaneous preterm birth (SPB) remains unclear. We conducted a nested case-control study from a prospective cohort in Shanxi Province, China, to explore their associations. In total, 126 pregnant women with SPB (cases) and 348 controls with term delivery were included. We measured the Hg concentrations in their serum (Hgs) and blood cell (Hgc) fractions and calculated the concentration ratio of Hg in serum to Hg in blood cells (Hgs/c). We found that only the Hgs/c in the case group was slightly higher than that in control group. The OR of Hgs/c associated with SPB risk was 1.57 [95%CI: 0.99-2.46] with adjusting confounders. After stratification by sampling time, the association above was only statistically significant in the first trimester. High Hgs/c may increase the risk of SPB in the first trimester among women with relatively low Hg exposure.

Bioaccessibility dependence of dietary exposure to dichlorodiphenyltrichloroethane and its metabolites and hexachlorocyclohexane isomers and their induced health risk: A case study in Beijing City, China.

Bioaccessibility is essential for evaluating dietary intake of contaminants. However, there is insufficient information on the dependence of dietary intake and risk assessment of dichlorodiphenyltrichloroethane and its metabolites (DDXs) and hexachlorocyclohexane isomers (HCHs) on bioaccessibility. Here, we investigated the bioaccessibilities of DDXs and HCHs in various foods and their influences on assessing exposure in the residents of Beijing City, China. Forty-three major foods in five types (fruit, vegetables, cereals, aquatic food, and meat) were sampled, and the bioaccessibility of DDXs and HCHs was evaluated using a static in vitro gastrointestinal digestion model. The bioaccessibility of DDXs in different food types ranked in the order of meat > vegetables > fruit > cereals > aquatic food, with mean ± standard deviation values of 62.2 ± 22.1%, 20.5 ± 10.6%, 12.4 ± 3.66%, 11.2 ± 9.69%, and 10.7 ± 4.97%, respectively. The highest average bioaccessibility of HCHs was found in meat (83.4 ± 14.2%), followed by fruit (41.0 ± 12.5%), vegetables (37.6 ± 18.1%), aquatic foods (24.2 ± 9.22%), and cereals (8.73 ± 4.07%). The estimated daily intakes (EDI) of the sum of DDXs and the sum of HCHs based on the bioaccessible concentration were only about 17% and 55% of the total EDI based on the residual concentration, respectively. Meat was found to play a more important role in EDI after bioaccessibility correction. The proportion of the population with potential non-carcinogenic and carcinogenic risks markedly decreased when considering bioaccessibility. It was concluded that bioaccessibility should be integrated into dietary exposure evaluation.

Internal metal(loid)s are potentially involved in the association between ambient fine particulate matter and blood pressure: A repeated-measurement study in north China.

The effects of ambient fine particulate matter (PM2.5) exposure on blood pressure have been widely reported. However, there remains uncertainty regarding the underlying roles of particulate matter components. We aimed to investigate the association between ambient PM2.5 exposure and blood pressure, as well as the potential effects of trace metal(loid)s, in a repeated-measurement study that enrolled women of childbearing age. Our study included 35 participants from Hebei Province, China, each of whom was visited for five times. During each visit, we conducted questionnaire surveys, measured blood pressure, and collected blood. The daily PM2.5 exposure of participants was estimated according to their residential addresses using a spatiotemporal model that combined monitoring data with satellite measurements and chemical-transport model simulations. This model was used to calculate average PM2.5 concentrations in 1, 3, 7, 15, 30, and 60 days prior to each visit. Serum concentrations of various trace metal(loid)s were measured. A linear mixed-effects model was used to investigate associations among study variables. Overall, the mean (standard deviation) 60 days PM2.5 concentration over all five visits was 108.1(43.3) µg/m3. PM2.5 concentration was positively associated with both systolic and diastolic blood pressures. Likewise, ambient PM2.5 concentration was positively associated with serum concentrations of manganese and arsenic, and negatively associated with serum concentrations of nickel, tin, and chromium. Only the serum concentration of molybdenum was negatively associated with systolic blood pressure. We concluded that ambient PM2.5 exposure may contribute to elevated blood pressure, potentially by interfering with internal intake of various metal(loid)s in the human body.

Highly sensitive determination of endocrine disrupting chemicals in foodstuffs through magnetic solid-phase extraction followed by high-performance liquid chromatography-tandem mass spectrometry.

BACKGROUND: Endocrine disrupting chemicals (EDCs), proved to be potential carcinogenic threats to human health, have received great concerns in food field. It was essential to develop effective methods to detect EDCs in food samples. The present study proposed an efficient method to determine trace EDCs including estrone (E1), 17ß-estradiol (E2), estriol (E3) and bisphenol A (BPA) based on magnetic solid-phase extraction (MSPE) coupled high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) in meat samples. RESULTS: Fe3 O4 @COF(TpBD)/TiO2 nanocomposites were synthesized via functionalization of magnetic covalent organic frameworks (COFs) with titanium dioxide (TiO2 ) nanoparticles, and used as absorbents of MSPE to enrich EDCs. The efficient EDCs enrichment relies on π-π stacking interaction, hydrogen bonding, and the interaction between titanium ions (IV, Ti4+ ) and hydroxyl groups in EDCs, which improves the selectivity and sensitivity. Under the optimized conditions, target EDCs were rapidly extracted through MSPE with 5 min. Combining Fe3 O4 @COF(TpBD)/TiO2 based MSPE and HPLC-MS/MS to determine EDCs, good linearities were observed with correlation coefficient (R2 ) ≥ 0.9989. The limits of detection (LODs) and limits of quantification (LOQs) were 0.13-0.41 µg kg-1 and 0.66-1.49 µg kg-1 , respectively. Moreover, the proposed method was successfully applied to real samples analysis. CONCLUSIONS: The established MSPE-HPLC-MS/MS method was successfully applied to determine EDCs in meat samples with rapidness, improved selectivity and sensitivity. It shows great prospects for EDCs detection in other complicated matrices. © 2020 Society of Chemical Industry.

Potential interference on the lipid metabolisms by serum copper in a women population: A repeated measurement study.

The relationship between excess copper (Cu) intake and lipid metabolic disorders is not well-studied, and most studies on this topic have a cross-sectional design. Here, we investigated the relationship between Cu exposure and blood lipid metabolism in women population, as well as potential mediation effects of oxidative stress and inflammation, using a repeated-measurement study. A total of 35 women in northern China were included, and each individual was visited for five times. Blood samples were collected, and the following serum biomarkers were analyzed: heme oxygenase-1 (HO-1), monocyte chemotactic protein-1 (MCP-1), interleukin (IL)-6, IL-8, and lipids [triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), and lipoprotein(a) (Lp(a))]. A linear mixed-effect model was used to analyze the associations between Cu and the individual biomarkers in serum. The results showed that Cu was positively associated with TG (ß = 0.0007, P = 0.01), TC (ß = 0.0006, P = 0.002), LDL (ß = 0.0004, P ≤ 0.001), and Lp(a) (ß = 0.0004, P = 0.01), but not associated with HDL (ß = 0.0001, P = 0.19). Likewise, serum Cu was positively associated with HO-1 (ß = 0.0004, P = 0.03) and negatively associated with MCP-1 (ß = -0.0006, P = 0.003) and IL-8 (ß = -0.002, P = 0.03). Among the biomarkers of oxidative stress, inflammation, and lipids in serum, only IL-8 was negatively associated with HDL (ß = -0.0004, P = 0.009). No other associations were observed. We conclude that high Cu exposure may elevate blood lipid levels as well as disturb processes related to oxidative stress and inflammation responses.

Differential analysis of FA-NNC, PCA-MLR, and PMF methods applied in source apportionment of PAHs in street dust.

Many source apportionment models have been applied to identify pollution sources, and differences often exist in the diagnostic results. The reasons causing these differences have not been fully elucidated. In this study, three receptor models, principal component analysis-multiple linear regression (PCA-MLR), positive matrix factorization (PMF), and factor analysis-nonnegative constraints (FA-NNC), were compared and applied for the analysis of 16 EPA priority polycyclic aromatic hydrocarbons (PAHs) adsorbed in street dust samples from Harbin City (China). The differences in the results were caused by different calculation approaches, including matrix decomposition, variable grouping extraction, and nonnegative constraints, especially between PCA-MLR and the other two models. PCA-MLR has no nonnegative constraints, making PCA-MLR less similar to the real world than the other two. Both PMF and FA-NNC have a nonnegative constraint process, which may be the main reason why their results were much more similar to each other than to those of PCA-MLR. PCA-MLR distinguishes variables into several groups that have the greatest variances from each other, whereas the other two methods find similarities among variables and extract them. In the case study of Harbin City, the contributions of mobile and industrial sources ranged from 47 to 69%, and the contributions of coal and other sources ranged from 30 to 52%. The recognized types of pollution sources were generally equivalent, but the proportional contributions were different. PCA-MLR performed best in calculating contributions, whereas PMF and FA-NNC were better in terms of source diagnosis.

Facile preparation of magnetic covalent organic framework-metal organic framework composite materials as effective adsorbents for the extraction and determination of sedatives by high-performance liquid chromatography/tandem mass spectrometry in meat samples.

RATIONALE: Sedatives, which are prone to cause residues in animals, have been abused in modern animal husbandry. Long-term consumption of contaminated meat products would be unfavorable to the human nervous system. Taking into account public health and food safety, it was essential to develop an effective method for the enrichment and detection of sedatives in meat. METHODS: Fe3 O4 @TbBd@ZIF-8 composites were synthesized by using Fe3 O4 nanoparticles as a magnetic core and 1,3,5-triformylbenzene (Tb) and benzidine (Bd) as two building blocks to form Fe3 O4 @TbBd. Furthermore, the zeolitic imidazolate framework-8 (ZIF-8) was modified on the surface of the Fe3 O4 @TbBd. In addition, Fe3 O4 @TbBd@ZIF-8 was used as a magnetic solid-phase extraction (MSPE) adsorbent of typical animal sedatives in pork samples. Mass spectrometry analysis was conducted by electrospray ionization triple-quadrupole mass spectrometry in positive-ion multiple reaction monitoring mode. RESULTS: By combining the optimized MSPE approach with high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS), an accurate and sensitive method for the determination of sedatives was developed. The method exhibited good linearity in the range of 0.03-70 µg/kg with the correlation coefficient (R2 ) ranging from 0.9982 to 0.9999, high sensitivity with limits of detection (LODs) ranging from 0.04 to 0.2 µg/kg, and high precision with relative standard deviation (RSD) less than 5.5%. The adsorption behaviors of Fe3 O4 @TbBd@ZIF-8 towards sedatives were more suitably described by a pseudo-second-order kinetic and Freundlich isotherm model. CONCLUSIONS: The proposed MSPE-HPLC/MS/MS method was successfully applied to the determination of sedatives in real samples and showed excellent applicability. Several sedatives were detected in the selected meat samples. The developed method was shown to be facile, sensitive and accurate for sedative detection and also showed great prospects for determination of sedatives from other complex samples.

Thiol radical-based chemical isotope labelling for sterols quantitation through high performance liquid chromatography-tandem mass spectrometry analysis.

Enlightened by the high specificity and reactivity of thiol radical toward allyl, here, we first established a rapid thiol radical-based chemical isotope-labelling (CIL) strategy coupled with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analysis for the quantitative profiling of sterols. In this strategy, N-(4-(carbazole-9-yl)-phenyl)-N-maleimide labelled derivative of ethylenedithiol (NCPM-d0-SH) and its deuterated analogue NCPM-d2-SH were employed as a novel pair of CIL reagents to efficiently label sterols. Under lighting condition, the thiol radical obtained from NCPM-d0/d2-SH attacks one allyl hydrogen in the B-ring of sterols to produce a reactive radical intermediate which can quickly react with another thiol radical to form the last labelled derivatives. This labelling reaction can rapidly complete only within 1.5 min. Absorbingly, the NCPM-d0-SH and NCPM-d2-SH labelled derivatives of sterols can produce two specific product ions (PIs) containing different isotope tags at m/z of 431.6 and 433.6 via collision induced dissociation, which were employed to develop the multiple reaction monitoring (MRM) mode-based analysis. According to the specific mass differences with a fixed value, the peak pairs with similar retention times can be easily extracted from the two PIs spectrums and designated as the candidates for the identification of sterols. NCPM-d0-SH and NCPM-d2-SH labelled derivatives of sterols can be readily distinguished from their several ion chromatograms. Thus, sterols from two samples labelled by different isotope tags were ionized at the same conditions and measured respectively, providing excellent identification and precise quantitation by compensating the matrix effect and instrument fluctuation during MS-based analysis. The detection sensitivities of thiol-containing drugs improved by 53.5-560.3-fold due to NCPM-labelling. The limits of detection (LODs) and the limits of quantitation (LOQs) were in the range of 0.15-0.40 µg kg-1 and 0.50-1.30 µg kg-1, respectively. Using the developed method, we quantitatively profiled five sterols in vegetable oils with good applicability. As promising, the proposed thiol radical-based CIL strategy is a potential platform for the quantitation of sterols.