[en] A gas chromatography/ion trap mass spectrometry method was developed for the analysis of simazine, atrazine, cyanazine, as well as the degradation products of atrazine, such as deethylatrazine and deisopropylatrazine in environmental water samples. Isotope dilution technique was applied for the quantitative analysis of atrazine in water at low ng/l levels. One liter of water sample spiked with stable isotope internal standard atrazine-d₅ was extracted with a C₁₈ solid-phase extraction cartridge. The analysis was performed on an ion trap mass spectrometer operated in MS/MS method. The extraction recoveries were in the range of 83-94% for the triazine herbicides in water at the concentrations of 24, 200, and 1000 ng/l, while poor recoveries were obtained for the degradation products of atrazine. The relative standard deviation (R.S.D.) were within the range of 3.2-16.1%. The detection limits of the method were between 0.75 and 12 ng/l when 1 l of water was analyzed. The method was successfully applied to analyze environmental water samples collected from a reservoir and a river in Hong Kong for atrazine detected at concentrations between 3.4 and 26 ng/l

[en] Highlights: • Mass spectrometry fragmentation behaviors of steroid hormones were studied and interpreted. • Diagnostic product ions were summarized for characterization of steroid hormones. • A total of 80 and 107 steroidal hormones were characterized or tentatively identified in male and female, respectively. -- Abstract: Steroid hormones, structural derivatives of cyclopentanoperhydrophenanthrene, play important roles in modulation of many physiological processes. Comprehensive characterization of steroid hormones is valuable for understanding the process of human life activities and even disease diagnosis. Hitherto systematical characterization of steroid hormones has been rarely investigated. Here, we presented an integrated method for human urine analysis based on ultra-high performance liquid chromatography-high resolution mass spectrometry in data-dependent acquisition mode with the following parallel reaction monitoring mode. To process the data acquired by two scan modes, a comparative study of standards’ fragmentation behaviors and diagnostic product ions (DPIs) were firstly conducted to facilitate the characterization of steroid hormones. The fragmentation behaviors, DPIs, elemental composition and double-bond equivalent were then simultaneously utilized for systematical characterization of steroid hormones in human urine. Consequently, fragmentation pathways and DPIs for all types of steroid hormones were comprehensively interpreted. It is interesting to find that dehydration is not restricted in the form of hydroxyl groups loss, elimination of the carbonyl oxygen could also generate dehydrated ions. Ultimately, a total of 80 and 107 steroidal hormones were characterized or tentatively identified in human urine of male and female, respectively. The proposed method is expected to provide valuable insights for chemical characterization in complex matrixes.

[en] Using MIL-101(Fe) as the source of carbon and Fe, a magnetic porous carbon (MPC) material with Fe₃C nanoparticles encapsulated in porous carbon was prepared through one-pot pyrolysis under N₂ atmosphere. With MPC as adsorption material, a stir bar sorptive-dispersive microextraction (SBSDME) method was proposed to extract and preconcentrate sulfonamides (SAs) prior to HPLC-DAD determination. To investigate their extraction ability, different MPC materials were prepared under different carbonization temperatures (600, 700, 800, 900, and 1000 °C). The material prepared under 900 °C (MPC-900) exhibited the highest extraction ability for SAs. The as-prepared MPC materials were also characterized by Raman spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, zeta potential, and other techniques. The main parameters that affect extraction were systematically studied. Under optimal conditions, favorable linearity (R² ≥ 0.9938) and detection limits (0.02–0.04 ng mL⁻¹) of sulfonamides were obtained. The average recoveries for spiked milk and lake water samples ranged from 76.9 to 109% and from 75.4 to 118% with RSDs of 3.10–9.63% and 1.71–11.3%, respectively. Sulfameter and sulfisoxazole were detected in milk sample. Sulfisoxazole was detected in the lake water sample. The MPC-900 material demonstrated excellent reusability. It can be reused 24 times with peak areas having no obvious decline. The method can be applied to extract ultra-trace compounds in complex sample matrices. Graphical abstract:

[en] Mesoporous graphitic carbon nitride (MCN) is shown to be a viable sorbent for the enrichment of sulfonamides (SAs). To overcome the difficulty of separating the sorbent from the matrix, a novel type kind of column-assisted dispersive solid-phase extraction (CA-dSPE) method was designed. The MCN was characterized by scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, fourier transform infrared spectroscopy and nitrogen adsorption-desorption measurements. The amount of sorbent, the pH value of the sample, the adsorption time, type and volume of the eluent and desorption time were optimized. The SAs were eluted from the sorbent with elution solvent of methanol containing 10% (v/v) ammonia and then submitted to HPLC analysis. Under the optimized conditions, the limits of detection for the SAs investigated (sulfadiazine, sulfameter, sulfachloropyridazine, sulfabenzamide and sulfadimethoxine) range from 20 to 5 pg·mL⁻¹. Satisfactory recoveries were obtained for spiked environmental water (90.1–110.5%) and milk samples (82.3–102.7%), with relative standard deviations of 0.5–3.8% and 1.1–4.4%, respectively. The method is simple, time saving and sensitive.

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[en] Mesoporous carbon hollow spheres coated with MoS₂ (C@MoS₂) were synthesized to obtain a material with large specific surface area, fast electron transfer efficiency and good water dispersibility. The composite material was applied as a matrix for the analysis of small molecules by surface-assisted laser desorption/ionization time-of-flight mass spectrometry (SALDI-TOF MS). The use of a core-shell C@MoS₂ matrix strongly reduces matrix background interferences and increases signal intensity in the analysis of sulfonamides antibiotics (SAs), cationic dyes, emodin, as well as estrogen and amino acids. The composite material was applied to the SALDI-TOF MS analysis of selected molecules in (spiked) real samples. The ionization mechanism of the core-shell C@MoS₂ as a matrix is discussed. The method exhibits low fragmentation interference, excellent ionization efficiency, high reproducibility and satisfactory salt tolerance.

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[en] Highlights: • Combined metabolomics and biological methods were employed to investigate BDE 47 effects on adipocyte differentiation. • BDE 47 exposure in cells increased lipid accumulation and gene expression of adipogenesis-related factors. • BDE 47 upregulated purine metabolism, mitochondrial respiration, and oxidative stress to enhance adipocyte differentiation. Adipocyte differentiation is closely associated with obesity and obesity-induced metabolic disorders. Epidemiological studies have demonstrated the association of obesity with environmental pollutants, such as polybrominated diphenyl ethers (PBDEs), common flame retardants in various consumer products. However, their obesogenic effects and mechanism are underexplored. We employed non-targeted metabolomics studies based on liquid chromatography-high resolution mass spectrometry to determine how 2,2′,4,4′-tetra-brominated biphenyl ether (BDE 47), one of the main congeners of PBDEs detected in human tissue, promotes adipocyte differentiation of mouse preadipocyte 3 T3-L1 cells. The promoting effects of BDE 47 exposure (5 or 10 μM) on adipocyte differentiation were confirmed by enhancing lipid accumulation and expression levels of biomarkers of adipogenesis. For the first time, we demonstrated that BDE 47 upregulated purine metabolism and altered glutathione metabolism to promote oxidative stress and uric acid production in adipocytes. BDE 47 also elevated mitochondrial respiration and glycolysis in adipocytes to induce more ATP to combat oxidative stress. Antioxidant treatments, including the suppression of xanthine oxidase, inhibited the effects of BDE 47 on inducing oxidative stress and lipid accumulation. BDE 47 may be a potential environmental obesogen by providing a permissive oxidative environment to induce adipocyte differentiation.

[en] Highlights: • PM_2_._5 induces heart mitochondrial morphological damage of rats. • Mitochondrial fission/fusion gene expression is important regulation mechanism. • Proinflammatoy cytokine level changes are accompanied with mitochondrial damage. • Alterations in oxidative stress and calcium homeostasis are focused on. - Abstract: Epidemiological studies suggested that ambient fine particulate matter (PM_2_._5) exposure was associated with cardiovascular disease. However, the underlying mechanism, especially the mitochondrial damage mechanism, of PM_2_._5-induced heart acute injury is still unclear. In this study, the alterations of mitochondrial morphology and mitochondrial fission/fusion gene expression, oxidative stress, calcium homeostasis and inflammation in hearts of rats exposed to PM_2_._5 with different dosages (0.375, 1.5, 6.0 and 24.0 mg/kg body weight) were investigated. The results indicated that the PM_2_._5 exposure induced pathological changes and ultra-structural damage in hearts such as mitochondrial swell and cristae disorder. Furthermore, PM_2_._5 exposure significantly increased specific mitochondrial fission/fusion gene (Fis1, Mfn1, Mfn2, Drp1 and OPA1) expression in rat hearts. These changes were accompanied by decreases of activities of superoxide dismutase (SOD), Na"+K"+-ATPase and Ca"2"+-ATPase and increases of levels of malondialdehyde (MDA), inducible nitric oxide synthase (iNOS) and nitric oxide (NO) as well as levels of pro-inflammatory mediators including TNF-α, IL-6 and IL-1β in rat hearts. The results implicate that mitochondrial damage, oxidative stress, cellular homeostasis imbalance and inflammation are potentially important mechanisms for the PM_2_._5-induced heart injury, and may have relations with cardiovascular disease

[en] Core-shell magnetic metal organic nanocrystals were synthesized and used as matrix for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Four nitropolycyclic aromatic hydrocarbons (nitro-PAHs) were successfully detected by using negative-ion MALDI-TOF MS without background interference. Furthermore, the magnetic nanocomposites (MNCs) coated with zeolitic imidazolate framework-8 (ZIF-8) showed excellent adsorption and enrichment capacity, and can be isolated with a magnet and directly spotted on the stainless steel plate for MALDI measurement. It was also analyzed nitro-PAHs in PM2.5 samples using the ZIF-8-coated magnetic nanocomposite as adsorbent and matrix.

[en] Highlights: • BDE-47 exposure accelerated gain of body weight and induced fatty liver in obese mice. • BDE-47 disrupted lipid metabolism to induce lipotoxicity in obese mice. • BDE-47-induced liver fibrosis in obese mice was associated with oxidative stress. • Lipidomics plays as significant role in exploring the mechanism of fatty liver and toxicity of BDE-47. -- Abstract: Exposure to polybrominated diphenyl ethers (PBDEs), is closely associated with the occurrence of obesity and non-alcoholic fatty liver disease (NAFLD), yet their pathological effects and underlying mechanisms remain unclear. To examine the role of 2, 2′, 4, 4′-tetrabromodiphenyl ether (BDE-47) in the progression of NAFLD under obese condition, male C57BL/6 J mice were fed with diet interaction for 15 weeks and subcutaneously injected with BDE-47 (7 mg/kg or 70 mg/kg) or the vehicle weekly. BDE-47 exposure (70 mg/kg) significantly elevated the body weight and worsened hepatic steatosis along with increased inflammation in high fat diet (HFD) fed mice. Furthermore, integration analysis of lipidomics and gene expression revealed that BDE-47 up-regulated triglyceride synthesis but suppressed lipid exportation and β oxidation, aggravating the accumulation of hepatic lipid in HFD fed mice. In addition, the increase of liver fibrosis, serum transaminase levels, as well as lipid peroxidation have been observed in mice co-treated with BDE-47 and HFD. Moreover, BDE-47-induced fibrogenic responses in hepatocytes were suppressed by antioxidants, which confirmed that BDE-47-induced liver fibrosis was tightly associated with oxidative stress. In conclusion, these results provided new and robust evidence for revealing the hepatoxicity of BDE-47 under obese condition and illustrated the underlying mechanism of BDE-47 induced liver fibrosis.

[en] Core-shell structured magnetic covalent organic framework (Fe₃O₄@COF) nanospheres were rapidly synthesized at room temperature using the monodisperse Fe₃O₄ nanoparticles (NPs) as magnetic core and benzene-1,3,5-tricarbaldehyde (BTA) and 3,3′-dihydroxybenzidine (DHBD) as two building blocks (denoted as Fe₃O₄@BTA-DHBD), respectively. They can serve as a mass spectrometry probe for rapid and high-throughput screening of bisphenols (BPs) from pharmaceuticals and personal care products (PPCPs) by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS). The Fe₃O₄@BTA-DHBD nanospheres showed some superior features involving average pore size distribution (2.82 nm), high magnetization values (42.5 emu g⁻¹), high specific surface area (82.96 m² g⁻¹), and good chemical/thermal stability. It was used as both ideal adsorbent for enrichment of BPs and new substrate to assist ionization in SELDI-TOF-MS. The method exhibited good linearity in the range 0.05–4000 ng mL⁻¹ with correlation coefficients (r) higher than 0.9920. Low limits of detection (LODs) (500 pg mL⁻¹ for bisphenol A (BPA), 2 pg mL⁻¹ for bisphenol B (BPB), 28 pg mL⁻¹ for bisphenol C (BPC), 60 pg mL⁻¹ for bisphenol F (BPF), 33 pg mL⁻¹ for bisphenol AF (BPAF), 200 pg mL⁻¹ for bisphenol BP (BPBP), 10 pg mL⁻¹ for bisphenol S (BPS), 90 pg mL⁻¹ for tetrabromobisphenol A (BPA(Br)₄), and 380 pg mL⁻¹ for tetrabromobisphenol S (BPS(Br)₄)) and good recoveries (80.6–115%) of BPs in PPCPs were achieved. The relative standard deviations (RSDs) of spot-to-spot (n = 10) and sample-to-sample (n = 5) were in the ranges 5–11% and 5–12%, respectively. The dual-function platform was successfully applied to the quantitative determination of BPs in PPCPs. It not only expanded the scope of the application of COFs but also provided an alternative strategy for the determination of hazardous compounds in PPCPs.