Metabolomics Analysis of the Responses to Partial Hepatectomy in Hepatocellular Carcinoma Patients

In this study, liquid chromatography/quadrupole time of flight mass spectrometry (LC/QTOFMS) was employed for investigating the metabolome of the sera collected from hepatocellular carcinoma (HCC) patients before and 3 to 5 months after partial hepatectomy. To investigate the changes in metabolic phenotypes after the hepatic resection, principal components analysis (PCA) and support vector machine (SVM) were performed for the data grouping and classification. Based on the obtained SVM model, mass spectrometry spectra, database searching as well as the confirmation from authentic standards, several differentiating metabolites were tentatively identified. To improve visualization, z-score plot and heat map display were performed, which exhibited the changes in concentration of the metabolites. As a result, depletion of circulating carnitine, reduced amino acid biosynthesis and increased rate of lipid peroxidation were observed. Meanwhile, up-regulation of hypoxanthine indicated that purine metabolism might serve as the salvage pathway. Collectively, the results reflected metabolic responses to surgical operation in HCC patients, suggesting perturbation of energy metabolism may occur in 3 to 5 months after the partial hepatectomy.

基于空间组学-临床影像技术的肿瘤精准诊断

作为全球公共卫生事件,恶性肿瘤严重影响人类健康、寿命和生活质量。肿瘤的发生发展经历了极其复杂的过程,表现出高度的时空异质性,影响其转移和耐药。为探寻这种异质性,多种临床影像技术和空间组学技术得以飞速发展。其中,临床影像技术准确率高但无法提供高通量的生物分子信息。空间组学技术可以获得标本的多种生物学特征,包括基因、蛋白和代谢等,但无法提供在体信息。将临床影像和空间组学技术相结合,可以优势互补,在临床和基础科学研究中具有较大应用前景,对于精确解析肿瘤的时空异质性和鉴别肿瘤分子分型、开展肿瘤精准诊断和发展进程预测等研究具有重要的推进作用。本文对该技术方法和特征进行了评述并展望了其发展趋势。

Multi-omics analysis of attenuated variant reveals potential evaluation marker of host damaging for SARS-CoV-2 variants

SARS-CoV-2 continues to threaten human society by generating novel variants via mutation and recombination.The high number of mutations that appeared in emerging variants not only enhanced their immune-escaping ability but also made it difficult to predict the pathogenicity and virulence based on viral nucleotide sequences.Molecular markers for evaluating the pathogenicity of new variants are therefore needed.By comparing host responses to wild-type and variants with attenuated pathogenicity at proteome and metabolome levels,six key molecules on the polyamine biosynthesis pathway including putrescine,SAM,dc-SAM,ODC1,SAMS,and SAMDC were found to be differentially upregulated and associated with pathogenicity of variants.To validate our discovery,human airway organoids were subsequently used which recapitulates SARS-CoV-2 replication in the airway epithelial cells of COVID-19 patients.Using ODC1 as a proof-ofconcept,differential activation of polyamine biosynthesis was found to be modulated by the renin-angiotensin system(RAS)and positively associated with ACE2 activity.Further experiments demonstrated that ODC1 expression could be differentially activated upon a panel of SARS-CoV-2 variants of concern(VOCs)and was found to be correlated with each VOCs’pathogenic properties.Particularly,the presented study revealed the discriminative ability of key molecules on polyamine biosynthesis as a predictive marker for virulence evaluation and assessment of SARS-CoV-2 variants in cell or organoid models.Our work,therefore,presented a practical strategy that could be potentially applied as an evaluation tool for the pathogenicity of current and emerging SARS-CoV-2 variants.

MALDI coupled with laser-postionization and trapped ion mobility spectrometry contribute to the enhanced detection of lipids in cancer cell spheroids

Cancer cell spheroids(CCS) are a valuable three-dimensional cell model in cancer studies because they could replicate numerous characteristics of solid tumors. Increasing researches have used matrix-assisted laser desorption/ionization mass spectrometry imaging(MALDI-MSI) to investigate the spatial distribution of endogenous compounds(e.g., lipids) in CCS. However, only limited lipid species can be detected owing to a low ion yield by using MALDI. Besides, it is still challenging to fully characterize the structural diversity of lipids due to the existence of isomeric/isobaric species. Here, we carried out the initial application of MALDI coupled with laser-postionization(MALDI-2) and trapped ion mobility spectrometry(TIMS) imaging in HCT116 colon CCS to address these challenges. We demonstrated that MALDI-2 is capable of detecting more number and classes of lipids in HCT116 colon CCS with higher signal intensities than MALDI. TIMS could successfully separate numerous isobaric/isomeric species of lipids in CCS. Interestingly, we found that some isomeric/isobaric species have totally different spatial distributions in colon CCS. Further MS/MS imaging analysis was employed to determine the compositions of fatty acid chains for isomeric species by examining disparities in signal intensities and spatial distributions of product ions. This work stresses the robust ability of TIMS and MALDI-2 imaging in analyzing endogenous lipids in CCS, which could potentially become powerful tools for future cancer studies.

Expansion Strategy-Driven Micron-Level Resolution Mass Spectrometry Imaging of Lipids in Mouse Brain Tissue

A novel method for enhanced resolution,termed expansion mass spectrometry imaging,has been developed for lipid mass spectrometry imaging,utilizing existing commercially available mass spectrometers without necessitating modifications.This approach involves embedding tissue sections in a swellable polyelectrolyte gel,with the target biomolecules indirectly anchored to the gel network.By employing matrix-assisted laser desorption ionization mass spectrometry imaging,the method has realized an enhanced spatial resolution that surpasses the conventional resolution limits of commercial instruments by approximately 4.5 fold.This enhancement permits the detailed visualization of intricate structures within the mouse brain at a subcellular level,with a lateral resolution nearing 1μm.As a physical technique for achieving resolution beyond standard capabilities,this readily adaptable approach presents a powerful tool for high-definition imaging in biological research.

Utilization of hydralazine as a reactive matrix for enhanced detection and on-MALDI-target derivatization of saccharides

Saccharides are a sort of ubiquitous and vital molecules within the whole life.However,the application of saccharides analysis with matrix-assisted laser desorption/ionization mass spectrometry(MALDI-MS)is restricted by their low ionization efficiency and the instability of the sialic acid fraction.Derivatization strategy based on nonreductive amination provides a good solution,however,this is often time consuming and may result in sample loss due to removal of excessive derivatization reagents.Herein,hydralazine(HZN)was utilized as a reactive matrix for labeling reducing saccharides directly on MALDI target which eliminated tedious sample preparation and avoided sample loss.After optimization,effective and reproducible on-MALDI-target derivatization of neutral and acidic saccharides was achieved in both positive and negative modes.Compared with 2,5-dihydroxybenzoic acid(DHB)and 9-aminoacridine(9-AA),HZN improved the detection sensitivity of reducing saccharides and provided more abundant fragment ions in MS/MS analysis.Moreover,26 kinds of neutral glycans and 5 kinds of sialic glycans were identified from ovalbumin(OVA)and bovine fetuin,respectively.Combined with the statistical models,this strategy could be used to distinguish and predict samples of 6 brands of beer,and discriminate 2 kinds of beer fermentation modes.In addition,HZN was applied for quantitative analysis of glucose in urine samples,and the obtained urine glucose concentrations of diabetic patients were consistent with the clinical test results,showing the potential of qualitative and quantitative analysis of reducing saccharides in complex samples.

Do wearing masks and preservatives have a combined effect on skin health?

Chemical exposure and local hypoxia caused by mask-wearing may result in skin physiology changes.The effects of methylparaben(MeP),a commonly used preservative in personal care products,and hypoxia on skin health were investigated by HaCaT cell and ICR mouse experiments.MeP exposure resulted in lipid peroxidation and interfered with cellular glutathione metabolism,while hypoxia treatment disturbed phenylalanine,tyrosine,and tryptophan biosynthesis pathways and energy metabolism to respond to oxidative stress.A hypoxic environment increased the perturbation of MeP on the purine metabolism in HaCaT cells,resulting in increased expression of proinflammatory cytokines.The synergistic effects were further validated in a mouse model with MeP dermal exposure and“mask-wearing”treatment.CAT,PPARG,and MMP2 were identified as possible key gene targets associated with skin health risks posed by MeP and hypoxia.Network toxicity analysis suggested a synergistic effect,indicating the risk of skin inflammation and skin barrier aging.

Chronic Real-Ambient PM_(2.5)Exposure Exacerbates Cardiovascular Risk via Amplifying Liver Injury in Mice Fed with a High-Fat and High-Cholesterol Diet

Epidemiology has associated fine particulate matter(PM_(2.5))exposure with an increased cardiovascular risk.However,the underlying mechanism,particularly from the liver perspective,remains unclear.Here,the influence of chronic PM_(2.5)exposure on cardiovascular risk in mice fed a high-fat and high-cholesterol diet(HFCD)was studied by using a real-world PM_(2.5)exposure system.Results showed that PM_(2.5)exposure elevated the serum levels of nonhigh-density lipoprotein cholesterol(non-HDL-C)and oxidized low-density lipoprotein(oxLDL)in HFCD-fed mice,demonstrating increased cardiovascular risk.To investigate the molecular mechanism,lipidomics and metabolomics analyses were conducted and revealed that PM_(2.5)exposure enhanced lipid accumulation and disturbed purine metabolism and glutathione metabolism in the liver of HFCD-fed mice,contributing to the elevated non-HDL-C levels and intensified oxidative stress.Moreover,PM_(2.5)exposure increased total cholesterol levels by upregulating Hmgcr expression and downregulating Cyp7a1 expression in the livers of HFCD-fed mice.The HDL-C level was reduced by inhibiting the hepatic Abca1 and Abcg1 expression and decreasing the levels of ApoA-I and LCAT.Additionally,the PM_(2.5)-induced pro-oxidative environment impeded the oxLDL clearance and further triggered inflammation,in turn exacerbating oxidative stress and oxLDL production.This study demonstrated a synergy of PM_(2.5)and HFCD on cardiovascular risk and illuminated the molecular mechanism in PM_(2.5)-susceptible populations.

Thiophene-based covalent organic frameworks for highly efficient iodine capture

Development of adsorbent materials for highly efficient iodine capture is high demand from the perspective of ecological environment and human health. Herein, the two kinds of thiophene-based covalent organic frameworks(COFs) with different morphologies were synthesized by solvothermal reaction using thieno[3,2-b]thiophene-2,5-dicarbaldehyde(TT) as the aldehyde monomer and tri(4-aminophenyl)benzene(PB) or tris(4-aminophenyl)amine(PA) as the amino monomer(denoted as PB-TT COF and PA-TT COF) and the as-prepared two heteroatoms-rich COFs possessed many excellent properties,including high thermal stability and abundant binding sites. Among them, PB-TT COF exhibited ultra-high iodine uptake up to 5.97 g/g in vapor, surpassing most of adsorbents previously reported, which was ascribed to its high specific surface(1305.3 m2/g). Interestingly, PA-TT COF with low specific surface(48.6m2/g) showed good adsorption ability for iodine in cyclohexane solution with uptake value of 750 mg/g,which was 2.38 times higher than that obtained with PB-TT COF due to its unique sheet-like morphology.Besides, the two COFs possessed good reusability, high selectivity and iodine retention ability. Based on experimental results, the adsorption mechanisms of both COFs were studied, revealing that iodine was captured by the physical-chemical adsorption. Furthermore, the both COFs showed excellent adsorption ability in real radioactive seawater treated safely, demonstrating their great potential in real environment.

Multicellular tumor spheroids bridge the gap between two-dimensional cancer cells and solid tumors: The role of lipid metabolism and distribution

Previous studies demonstrated that three-dimensional(3D) multicellular tumor spheroids(MCTS) could more closely mimic solid tumors than two-dimensional(2D) cancer cells in terms of the spatial structure, extracellular matrix-cell interaction, and gene expression pattern. However, no study has been reported on the differences in lipid metabolism and distribution among 2D cancer cells, MCTS, and solid tumors. Here, we used Hep G2 liver cancer cell lines to establish these three cancer models. The variations of lipid profiles and spatial distribution among them were explored by using mass spectrometry-based lipidomics and matrix-assisted laser desorption/ionization mass spectrometry imaging(MSI). The results revealed that MCTS, relative to 2D cells, had more shared lipid species with solid tumors. Furthermore,MCTS contained more comparable characteristics than 2D cells to solid tumors with respect to the relative abundance of most lipid classes and mass spectra patterns. MSI data showed that 46 of 71 lipids had similar spatial distribution between solid tumors and MCTS, while lipids in 2D cells had no specific spatial distribution. Interestingly, most of detected lipid species in sphingolipids and glycerolipids preferred locating in the necrotic region to the proliferative region of solid tumors and MCTS. Taken together, our study provides the evidence of lipid metabolism and distribution demonstrating that MCTS are a more suitable in vitro model to mimic solid tumors, which may offer insights into tumor metabolism and microenvironment.

Constructing cactus-like mixed dimensional MOF@MOF as sorbent for extraction of bisphenols from environmental water

Metal-organic frameworks(MOFs)received considerable attention to adsorption and removal of various environmental pollutants because of some inherent advantages.However,it is challenging but meaningful to design and fabricate hierarchical mixed-dimensional MOFs with synergistic effects to enhance the performance for removal and preconcentration of environmental pollutants.Herein,a new hierarchical two-dimensional(2D)-three-dimensional(3D)mixed-dimensional cactus-like MOF@MOF hybrid material(PCN-134@Zr-BTB)was prepared by in-situ growth of 2D MOF nanosheets(Zr-BTB)on the surface of 3D MOF(PCN-134).The PCN-134@Zr-BTB composites combine the advantages of 2D and 3D MOFs with extensive mesoporous structures and large surface area for effective removal and enrichment of bisphenols(BPs).In comparison with pristine PCN-134 and Zr-BTB materials,the PCN-134@Zr-BTB hybrid material presented excellent adsorption performance for BPs.The adsorption isotherms are consistent with the Langmuir model,and the maximum adsorption capacity of four bisphenols(BPs)ranged from 135.1 mg/g to 628.9 mg/g.The adsorption kinetics are in accordance with the pseudo-second-order model.The recoveries ranged from 72.8%to 108%.The limits of detection were calculated at 0.02-0.03 ng/mL.The enrichment factors were calculated in the range of 310-374.According to FT-IR and XPS analysis,the main adsorption mechanisms are hydrogen bonding and π-π stacking.Nevertheless,this work provides a new and convenient strategy for the preparation of new hierarchical mixed-dimensional MOF@MOF(PCN-134@Zr-BTB)hybrid material for extraction and enrichment of BPs from aqueous matrix.

Urine biomarkers discovery by metabolomics and machine learning for Parkinson’s disease diagnoses

Parkinson’s disease(PD)is a complex neurological disorder that typically worsens with age.A wide range of pathologies makes PD a very heterogeneous condition,and there are currently no reliable diagnostic tests for this disease.The application of metabolomics to the study of PD has the potential to identify disease biomarkers through the systematic evaluation of metabolites.In this study,urine metabolic profiles of 215 urine samples from 104 PD patients and 111 healthy individuals were assessed based on liquid chromatography-mass spectrometry.The urine metabolic profile was first evaluated with partial leastsquares discriminant analysis,and then we integrated the metabolomic data with ensemble machine learning techniques using the voting strategy to achieve better predictive performance.A combination of 8-metabolite predictive panel performed well with an accuracy of over 90.7%.Compared to control subjects,PD patients had higher levels of 3-methoxytyramine,N-acetyl-l-tyrosine,orotic acid,uric acid,vanillic acid,and xanthine,and lower levels of 3,3-dimethylglutaric acid and imidazolelactic acid in their urine.The multi-metabolite prediction model developed in this study can serve as an initial point for future clinical studies.

Adverse effects of triclosan on kidney in mice: Implication of lipid metabolism disorders

Triclosan(TCS)is a ubiquitous antimicrobial used in daily consumer products.Previous reports have shown that TCS could induce hepatotoxicity,endocrine disruption,disturbance on immune function and impaired thyroid function.Kidney is critical in the elimination of toxins,while the effects of TCS on kidney have not yet been well-characterized.The aim of the present study was to investigate the effects of TCS exposure on kidney function and the possible underlying mechanisms in mice.Male C57BL/6 mice were orally exposed to TCS with the doses of 10 and 100 mg/(kg•day)for 13 weeks.TCS was dissolved in dimethyl sulfoxide(DMSO)and diluted by corn oil for exposure.Corn oil containing DMSO was used as vehicle control.Serum and kidney tissues were collected for study.Biomarkers associated with kidney function,oxidative stress,inflammation and fibrosis were assessed.Our results showed that TCS could cause renal injury as was revealed by increased levels of renal function markers including serum creatinine,urea nitrogen and uric acid,as well as increased oxidative stress,pro-inflammatory cytokines and fibroticmarkers in a dose dependent manner,whichweremore significantly in 100 mg/(kg•day)group.Mass spectrometry-based analysis of metabolites relatedwith lipid metabolism demonstrated the occurrence of lipid accumulation and defective fatty acid oxidation in 100 mg/(kg•day)TCS-exposed mouse kidney.These processes might lead to lipotoxicity and energy depletion,thus resulting in kidney fibrosis and functional decline.Taken together,the present study demonstrated that TCS could induce lipid accumulation and fatty acid metabolism disturbance in mouse kidney,whichmight contribute to renal function impairment.The present study further widens our insights into the adverse effects of TCS.

Analogous comparison unravels heightened antiviral defense and boosted viral infection upon immunosuppression in bat organoids

Horseshoe bats host numerous SARS-related coronaviruses without overt disease signs.Bat intestinal organoids,a unique model of bat intestinal epithelium,allow direct comparison with human intestinal organoids.We sought to unravel the cellular mechanism(s)underlying bat tolerance of coronaviruses by comparing the innate immunity in bat and human organoids.We optimized the culture medium,which enabled a consecutive passage of bat intestinal organoids for over one year.Basal expression levels of IFNs and IFN-stimulated genes were higher in bat organoids than in their human counterparts.Notably,bat organoids mounted a more rapid,robust and prolonged antiviral defense than human organoids upon Poly(I:C)stimulation.TLR3 and RLR might be the conserved pathways mediating antiviral response in bat and human intestinal organoids.The susceptibility of bat organoids to a bat coronavirus CoV-HKU4,but resistance to EV-71,an enterovirus of exclusive human origin,indicated that bat organoids adequately recapitulated the authentic susceptibility of bats to certain viruses.Importantly,TLR3/RLR inhibition in bat organoids significantly boosted viral growth in the early phase after SARS-CoV-2 or CoV-HKU4 infection.Collectively,the higher basal expression of antiviral genes,especially more rapid and robust induction of innate immune response,empowered bat cells to curtail virus propagation in the early phase of infection.

Drugs,sex,and enhancement:Threats to sports integrity at the Olympics

BACKGROUND.The Olympic Games represents a majestic sporting showcase on a uniquely global scale.The Paris 2024 Olympics could mark the start of a new era for the Olympic Movement.This viewpoint focuses on three existential threats to modern Olympic Games:doping,gender issues,and enhancement,while cutting-edge research and science need to be at the heart of a concerted reaction to restore integrity of competition and protect the concept of“true”sport.Performance enhancement in the context of sport denotes or relates to a drug or other substance or method used with the prospect of improving an athlete’s performance;specifically,substances and methods that enhance any number of components of physical and mental performance,such as agility,speed,strength,power,endurance,and competition preparation and execution.

Investigation of PM_(2.5) pollution during COVID-19 pandemic in Guangzhou,China

The COVID-19 pandemic has raised awareness about various environmental issues,includ-ing PM_(2.5) pollution.Here,PM_(2.5) pollution during the COVID-19 lockdown was traced and an-alyzed to clarify the sources and factors influencing PM_(2.5) in Guangzhou,with an emphasis on heavy pollution.The lockdown led to large reductions in industrial and traffic emissions,which significantly reduced PM_(2.5) concentrations in Guangzhou.Interestingly,the trend of PM_(2.5) concentrations was not consistent with traffic and industrial emissions,as minimum concentrations were observed in the fourth period(3/01-3/31,22.45 μg/m^(3))of the lockdown.However,the concentrations of other gaseous pollutants,e.g.,SO_(2),NO_(2) and CO,were corre-lated with industrial and traffic emissions,and the lowest values were noticed in the sec-ond period(1/24-2/0_(3))of the lockdown.Meteorological correlation analysis revealed that the decreased PM_(2.5) concentrations during COVID-19 can be mainly attributed to decreased in-dustrial and traffic emissions rather than meteorological conditions.When meteorological factors were included in the PM_(2.5) composition and backward trajectory analyses,we found that long-distance transportation and secondary pollution offset the reduction of primary emissions in the second and third stages of the pandemic.Notably,industrial PM_(2.5) emis-sions from western,southern and southeastern Guangzhou play an important role in the formation of heavy pollution events.Our results not only verify the importance of control-ling traffic and industrial emissions,but also provide targets for further improvements in PM_(2.5) pollution.

Airborne fine particulate matter induces cognitive and emotional disorders in offspring mice exposed during pregnancy

Gestational exposure to PM_(2.5) is associated with adverse postnatal outcomes.PM_(2.5) can enter alveoli by using intratracheal instillation,even penetrate through lung cells into the blood circulation.Subsequently,they are transferred across the placenta and fetal blood brain barrier,causing the adverse birth outcomes of offspring.This study demonstrated that the gestational exposure resulted in cognitive and emotional disorders in female offspring although the offspring were not exposed to PM_(2.5).Placental metabolic pathways modulated fetal brain development and played a pivotal role for maternal-placentalfetal interactions in the fetal programming of adult behavioral and mental disorders.Samples of fetus,offspring hippocampus and placenta from the mice exposed to PM_(2.5) were investigated using a comprehensive approach including mass spectrometry-based lipidomics and three-dimensional imaging.The exposure induced the neuro-degeneration in hippocampus,impairment of placental cytoarchitecture,and reprogramming of lipidome,which might affect the modulation of maternal-fetal cross-talk and result in the behavior disorders of offspring.The variation of spatial distribution of lipids was profoundly affected in dorsal pallium and hippocampal formation regions of fetal brain,offspring hippocampus,as well as labyrinth and junctional zones of placenta.The abundance alteration of lipid markers associated with neurodegenerative diseases was validated in transgenic mouse model with Alzheimer’s disease and human cerebrospinal fluid from patients with Parkinson’s disease.The finding could help with the selection of more suitable heterogeneous-related substructures targeting PM_(2.5) exposure and the exploration of PM_(2.5)-induced toxicological effects on neurodegenerative diseases.

Trimester-specific urinary metabolome alterations associated with gestational diabetes mellitus:A study in different pregnancy stages

Gestational diabetes mellitus(GDM),a frequently-occurring disease during pregnancy,may cause some adverse healthy outcome of both mother and offspring.However,the knowledge about metabolite alterations during the pathogenesis and development process is limited.Here,a large longitudinal nontargeted metabolomics study of 195 pregnant women(64 women with subsequently developed GDM and131 healthy controls)was conducted.Each participant provided urine samples at three timepoints during early,middle and late pregnancy,respectively.The metabolic profiles of 585 urine samples(195×3)were measured by using ultra-high performance liquid chromatography coupled with Orbitrap high-resolution mass spectrometry.Among the 56 identified metabolites,the levels of eight metabolites increased and three ones decreased in the first trimester,the concentration of one metabolite increased and those of 20 decreased in the second trimester,as well as the levels of five metabolites increased and two decreased in the third trimester.After false discovery rate correction,the levels of valine and 5-acetamidovalerate in GDM group significantly increased in the first trimester,the levels of 1-methylguanine and 1,3-dihydro-(2 H)-indol-2-one significantly decreased in the second trimester and three metabolites(threonine,OH-octanedioyl-carnitine and pimelylcarnitine)increased and N-acetyltryptophan decreased in the third trimester,respectively.Six metabolites,such as pantothenic acid and threonine,had significant interaction effects between gestational stage(different trimester)and group(GDM or control).The differential metabolites were involved in“tryptophan metabolism”,“purine metabolism”,“valine,leucine and isoleucine degradation”and other pathways.The findings may provide insights into further pathogenesis study of GDM.

Risk assessment of dietary exposure to PCDD/Fs, DL-PCBs and NDL-PCBs of Hong Kong resident

Concentrations of PCDD/Fs, dioxin-like PCBs as well as six indicator PCBs were determined in animal origin foods collected from Hong Kong retail market during 2008-2010. The dietary intake of an average Hong Kong adult resident was estimated to be 0.806-0.833 pg WHO-TEQ kg^-1 b.w. d^-1 of dioxin-like compounds, lower than the tolerable daily intake introduced by WHO. The 95th percentile consumer were exposed by dietary at the level of 2.72 to 2.81 pg WHO-TEQ kg^-1 b.w. d^-1 or 81.6-84.3 pg WHO-TEQ kg^-1 b.w. month^-1 , higher than 70 pg WHO-TEQ kg t b.w. month^-1. DL-PCBs contributed 49.2% of total TEQ intake. The daily intake of indicator PCB was 2.83 ng kg^-1 b.w. d^-1. Approximately 2/3 of dietary intake of dioxin-like compounds came from sea food products. Ten brands of infant formula products were tested and the potential dietary intake of formula-fed infants of Hong Kong was estimated to be 1.46-1.58 pg WHO-TEQ kg^-1 b.w. d^-1 during 1st month and decreases afterwards.

Facile preparation of nano-g-C_(3)N_(4)/UiO-66-NH_(2) composite as sorbent for high-efficient extraction and preconcentration of food colorants prior to HPLC analysis

In this work,the nano-g-C_(3)N_(4)/Ui O-66-NH_(2)composite was prepared by one-step solvothermal method.The as-prepared composite was characterized by scanning electron microscopy,Brunner-Emmet-Teller measurement,energy dispersive spectrometer,X-ray diffraction,and Fourier transform infrared spectroscopy.By using nano-g-C_(3)N_(4)/Ui O-66-NH_(2)composite as sorbent,a dispersive solid-phase extraction coupled with high-performance liquid chromatography was developed to sensitive analysis of food colorants including tartrazine,amaranth,carmine,sunset yellow,allura red and bright blue.The experiment parameters including the amount of sorbent,adsorption time,the p H of adsorption solution,desorption time,desorption solvent,the p H of desorption solution as well as the proportion between desorption solvent and buffer solvent were investigated.Under the optimized conditions,the limits of detection(S/N=3) and limits of quantitation (S/N=10) were determined in the ranges of 0.08-0.8 and 0.2-2.0 ng/m L,respectively.With the developed sample pretreatment method,carmine and brilliant blue were determined from blueberry juice by HPLC-DAD.The contents were calculated as 1.53μg/m L and0.17μg/mL,respectively.