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Chinese Journal of Chromatography
2025, Vol. 43, No. 1
Online: 08 January 2025

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CONTENTS 2025, 43 (1):  0-0.  Abstract ( 28 )   PDF (3958KB) ( 28 )

Preface

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Preface for Special Issue of Environmental and Health Analysis WANG Hailin, LAI Weiyi 2025, 43 (1):  1-2.  DOI: 10.3724/SP.J.1123.2024.11027 Abstract ( 42 )   HTML ( 19 )   PDF (893KB) ( 29 )

Reviews

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Current advances in the analysis of free RNA modified nucleosides by high performance liquid chromatography-tandem mass spectrometry ZHANG Lyuye, ZHANG Weibing, WANG Hailin 2025, 43 (1):  3-12.  DOI: 10.3724/SP.J.1123.2024.07004 Abstract ( 122 )   HTML ( 14 )   PDF (1545KB) ( 89 )   Post-transcriptional ribonucleic acid (RNA) modifications play crucial roles in regulating gene expression, with both eukaryotic and prokaryotic RNA exhibiting more than 170 distinct and ubiquitous modifications. RNA turnover generates numerous free nucleosides, including unmodified nucleosides and a variety of modified ones. Unlike unmodified nucleosides, modified nucleosides are not further degraded or used in the salvage-synthesis pathway owing to a lack of specific enzymes, which leads to the cytosolic accumulation or cellular efflux of modified nucleosides. These modified nucleosides can act as signaling molecules that regulate downstream pathways once transported to the extracellular space; alternatively, they are metabolized in the bloodstream and excreted in urine. Metabolized modified nucleosides are altered by cellular stress responses and mediate abnormal physiological states. Changes in the urinary and blood levels of modified nucleosides associated with cancer can serve as biomarkers for disease. Therefore, identifying and accurately quantifying nucleosides is vital for understanding RNA degradation and associated patterns of nucleoside metabolism. Such analyses are helpful when studying the biological functions and potential clinical applications of modified nucleosides. In this regard, high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) offers significant advantages in terms of sensitivity, selectivity, and efficiency, and has been widely used to analyze DNA and RNA nucleosides/nucleotides and their analogues. Multiple MS detection patterns and quantification methods have been established to detect nucleosides in biological samples, including cultured cells, urine, blood, and tissue samples. However, the development of an accurate HPLC-MS/MS method faces several challenges. Firstly, the presence of a complex biological matrix that contains macromolecules, small molecules, and salts can interfere with analysis. Salts and co-eluting substances in the extraction solution often affect mass-spectrometric responses for target analytes. Secondly, various nucleosides are present in vastly different abundances, with contents varying by up to four orders of magnitude; hence, accurately quantifying multiple nucleosides in a single assay is challenging. Thirdly, N-glycosidic bonds are favorably cleaved in most nucleosides during MS to produce the same characteristic fragment ions, which are often accompanied by nucleobases. This tendency poses challenges for distinguishing structural isomers and mass-analogs of modified nucleosides by MS. Post-transcriptional chemical modifications include methylation, hydroxylation, sulfur/oxygen substitution, and side-chain additions. Developing a unified method for simultaneously screening modified nucleosides is difficult owing to biochemical diversity; consequently, there is a need for advanced HPLC-MS/MS method capable of accurately quantifying such nucleosides. This review summarizes the development and applications of LC-MS technologies for analyzing endogenous nucleosides, covering sample preparation, chromatographic-separation and mass-spectrometric-detection conditions, and the development of quantification methods. Additionally, we discuss applications aimed at detecting and quantifying RNA-derived modified nucleosides in biological samples. The applications of HPLC-MS/MS technology are highlighted, the regulation and function of free modified nucleosides are discussed, and the potential functions of modified nucleosides as disease biomarkers for clinical applications are introduced.

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Research advances in the transplacental transfer efficiencies of environmental pollutants YUAN Keyu, XIONG Jun, YUAN Bifeng 2025, 43 (1):  13-21.  DOI: 10.3724/SP.J.1123.2024.07002 Abstract ( 43 )   HTML ( 7 )   PDF (1184KB) ( 29 )   Industrialization has led to significant increases in the types and quantities of pollutants, with environmental pollutants widely present in various media, including the air, food, and everyday items. These pollutants can enter the human body via multiple pathways, including ingestion through food and absorption through the skin; this intrusion can disrupt the production, release, and circulation of hormones in the body, resulting in a range of illnesses that affect the reproductive, endocrine, and nervous systems. Consequently, these pollutants pose substantial risks to human health. In particular, fetuses are highly sensitive to environmental pollutants during critical stages of development, and exposure during periods of growth and development can result in more-obvious and severe health hazards that can lead to preterm birth, low birth weight, and fetal malformations. The placenta acts as a barrier between the mother and fetus, and selectively filters certain pollutants. While some pollutants remain in the maternal bloodstream, others cross the placental barrier into the fetal umbilical blood through passive diffusion, placental transport proteins, or endocytosis. The transplacental transfer efficiency (TTE) is the ratio of the level of the pollutant in the umbilical blood to that in the maternal blood, and is a valuable metric for evaluating the ability of a pollutant to breach the placental barrier. A higher TTE implies that a larger proportion of pollutants are transferred from the mother to the fetus, thereby amplifying the potential risks to the fetus. Mass spectrometry-based detection methods are extensively used in the chemical and environmental sciences because they are exceptionally sensitive and highly resolving. This analytical technique involves ionizing compounds within a sample and identifying them based on their distinct mass-to-charge ratios; it enables both qualitative and quantitative analyses of various environmental pollutants. Current methodologies for examining the TTE of a pollutant include in-vitro experiments, animal studies, epidemiologic studies, and model calculation; these approaches help to evaluate the transfer of pollutants from mother to fetus via the placenta. Analyzing the TTEs of different chemicals enables high-risk pollutants to be identified and provides an understanding of their abilities to cross the placenta. Research on the transplacental transfer of environmental pollutants has focused mainly on per- and polyfluoroalkyl substances (PFASs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs), with relatively few studies on the TTEs of other pollutants reported. Pollutant transfer through the placenta is a complex process that is influenced by factors that include the physical and chemical properties of the pollutant (e.g., molecular mass, solubility, and lipophilicity), maternal factors (e.g., maternal health and lifestyle, maternal genetics, environmental conditions, and socioeconomic status), and placental characteristics (e.g., placental maturity, placental blood flow, transport proteins, and metabolic enzymes). This review summarizes recent advances in research on the TTEs of environmental pollutants, focusing on analytical methods, the TTEs of PFASs, PBDEs, PCBs, and OCPs, and the pivotal factors that influence TTEs. Studying the TTEs of pollutants enables their characteristics to be elucidated, thereby providing support data for research on the exposure, transfer, and accumulation of pollutants in the human body, as well as a theoretical framework for understanding the mechanism of transplacental transfer of environmental pollutants. This research is expected to play a vital role in assessing the impact of environmental pollutants on the health of pregnant women and their fetuses.

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Progress in applications of ambient ionization mass spectrometry for lipids identification WANG Xiaorong, YIN Yiyan, OUYANG Jin, NA Na 2025, 43 (1):  22-32.  DOI: 10.3724/SP.J.1123.2024.06007 Abstract ( 43 )   HTML ( 4 )   PDF (3371KB) ( 19 )   Lipids are indispensable components of living organisms and play pivotal roles in cell-membrane fluidity, energy provision, and neurotransmitter transmission and transport. Lipids can act as potential biomarkers of diseases given their abilities to indicate cell-growth status. For example, the lipid-metabolism processes of cancer cells are distinct from those of normal cells owing to their rapid proliferation and adaptation to ever-changing biological environments. As a result, the ability to rapidly detect, identify, and monitor lipid components is critical for tracking life-related processes and may enhance cancer diagnosis and treatment efficacy. Mass spectrometry (MS) is regarded to be among the most efficient methods for directly obtaining molecular-structural information, and is distinctly advantageous for identifying lipids. Recent years have witnessed the emergence of ambient mass spectrometry (AMS), which enables direct analyte sampling and ionization without the need for sample preprocessing. These characteristics endow AMS with special advantages for identifying and monitoring lipids. Furthermore, the ongoing development of soft ionization technologies has led to the widespread use of AMS for the detection of complex and diverse lipid molecules. Electrospray ionization (ESI) is a gentle ionization method that can be used to detect medium-to-high-polarity compounds and provide detailed chemical information for lipids by producing a fine mist of charged droplets from a liquid sample. Consequently, a series of ESI-based ionization methods have been developed for fabricating different AMS systems capable of rapidly detecting lipids in a simple manner. For example, desorption electrospray ionization (DESI) is among the most extensively employed ambient ionization techniques, and has been used to detect a wide range of samples, including solids, liquids, and gases. DESI involves spraying a charged solvent onto the surface of a sample, after which the solvent is desorbed, the analyte is ionized, and the generated ions are transferred to the detector of the mass spectrometer via a gas plume. DESI can easily and precisely regulate the sampling space, thereby offering a highly effective approach for the in-situ detection of lipids from tissue samples. Additionally, single-cell lipid analysis is limited by small cell volumes, complex cellular matrices, and minimal absolute amounts of analyte. Common detection methods for single cells include flow cytometry and fluorescence microscopy, both of which require fluorescent labeling to detect specific target molecules, which limits detection selectivity and reproducibility to some extent. ESI-based single-cell mass spectrometry has emerged as a more-effective method for detecting cellular lipids owing to advantages that include high sensitivity, low sample consumption, high throughput, and multiple-detection capabilities. Moreover, lipid chemical diversity poses a significant challenge for determining structural details. Therefore, AMS-based lipid detection has been augmented with a series of chemical-treatment methods that provide more-comprehensive structural information for lipids. For example, diverse gas-phase dissociation techniques have been used to discriminate between lipid C=C-bond isomers and their sn-positions. Strategies that involve chemically modifying specific target C=C bonds prior to MS detection have also been employed. For example, the Paternò-Büchi (P-B) photochemical reaction oxidizes C=C bonds in unsaturated lipids to form oxetane structures, C=C bonds can be epoxidized to form the corresponding oxaziridines, the N-H aziridination reaction converts C=C bonds into aziridines, and the 1ΔO2 ene reaction adds an OOH group to a C=C bond. In this review, we discuss various environmental ionization techniques for lipid AMS developed over the past five years, with an emphasis on typical chemical strategies used to analyze lipid fine structures. Obtaining a high-coverage, high-sensitivity lipid-detection platform based on AMS remains challenging and requires further in-depth studies despite significant improvements in lipid MS-based detection techniques.

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Advances in molecular networking technology for discovering emerging contaminants and transformation products TAN Xiaomei, ZHANG Yuwei, JIAO Zhaoyu, YU Nanyang, WEI Si 2025, 43 (1):  33-42.  DOI: 10.3724/SP.J.1123.2024.03014 Abstract ( 140 )   HTML ( 5 )   PDF (886KB) ( 69 )   Emerging contaminants and their transformation products are widely distributed in the environment. These pollutants carry unknown risks owing to their persistence, migration, and toxicity. The wide variety and complex structures of these substances render them difficult to identify using only target analysis. Suspect screening analysis can identify more substances than target analysis in a single run. However, this analysis method is based on limited data and cannot meet the growing demand for compound identification, especially for emerging contaminants and their transformation products with unknown information. The development of high-resolution mass spectrometry technology has promoted the applications of nontarget analysis in the environmental field, especially for identifying unknown transformation products. At present, the challenges of nontarget analysis include the difficulty of finding compounds of interest and their transformation products from complex data. Molecular networking calculates the similarity between mass spectra based on an improved cosine similarity algorithm. This method can cluster molecular families with similar structures, achieve visualization and a collection of massive mass spectral datasets, and promote the annotation of pollutants through networks and communities. Molecular networking can globally organize and systematically interpret complex tandem mass spectral datasets, providing a new direction for nontarget analysis. This technology was first used in proteomics and gradually introduced into metabolomics for the discovery of new natural products. Recently, it has been introduced into the environmental field for the study of various man-made chemicals, particularly for the discovery of emerging contaminants and their transformation products. In this paper, we introduce a molecular networking analysis method based on high-resolution tandem mass spectrometry and describe its applications in the nontargeted screening of emerging contaminants, focusing on the technical principles, workflow, application status, and future development prospects. This paper discusses the applications of molecular networking technology in the detection of emerging contaminants and their transformation products such as drugs, perfluorinated compounds, and disinfection byproducts. Molecular networking technology is widely applicable to the screening of emerging contaminants in various environmental media, revealing the full range of pollutants in the environment and promoting studies on the environmental behavior and toxicological properties of these compounds.

Mini-reviews

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Recent progress in mass spectrometry imaging using nanospray desorption electrospray ionization WANG Jingbo, LI Xiaolan, FAN Ruixia, LÜ Ping, YIN Ruichuan 2025, 43 (1):  43-49.  DOI: 10.3724/SP.J.1123.2024.07013 Abstract ( 36 )   HTML ( 5 )   PDF (2375KB) ( 20 )   Ambient mass spectrometry imaging (MSI) enables hundreds of analytes in tissue sections to be directly mapped at atmospheric pressure with minimal sample preparation. This field is currently experiencing rapid growth, with numerous reported ambient ionization techniques resulting in a “hundred flowers bloom” situation. Nanospray desorption electrospray ionization (nano-DESI), developed by the Laskin group in 2010, is a widely used liquid-extraction-based ambient ionization technique that was first used for mass spectrometry imaging of tissue in 2012. The nano-DESI probe comprises a primary capillary and a nanospray capillary, with the latter efficiently transferring analyte-containing droplets via a tiny liquid bridge formed between the probe and sample surface, thereby enabling nanoelectrospray ionization (nano-ESI) in front of the inlet of a mass spectrometer. The advantages of nano-DESI MSI include minimal sample preparation, high spatial resolution, and high sensitivity. These features are well-suited for imaging various sample types, including frozen tissue sections, microbial communities, and environmental samples. A PubMed-database search using the “nano-DESI” keyword revealed 72 related articles in the 2010-2024 period, with 34 of them published between 2021 and 2024, which indicates that nano-DESI has rapidly developed as an ambient ionization technique over recent years. Herein, we briefly introduce key nano-DESI-MSI research progress reported in the past three years with the aim of better understanding and facilitating the use of this technology. We first discuss advances in ion-source development. Since no commercial nano-DESI source exists, designing and constructing ion sources remain technical challenges that limit its development. Nano-DESI has been successfully coupled with various types of mass spectrometer, including LTQ Orbitrap, quadrupole-Orbitrap (Q Exactive), 6560 IM QTOF, timsTOF Pro2, triple quadrupole, and FTICR. These couplings have significantly expanded the applications range of the nano-DESI technique. Secondly, lipid analysis is a major nano-DESI-MSI applications area. While the complexities of lipid structures present great challenges for nano-DESI MSI, new nano-DESI coupling techniques have enabled the identification and imaging of fine lipid structures. Several novel imaging methods have recently been introduced to address difficulties associated with identifying lipid structures, such as distinguishing carbon-carbon double bonds (C=C) and sn-positional isomers. We finally highlight recent research progress in the nano-DESI MSI of intact protein assembles and proteoforms, which is a growing hotspot in the field. Unlike small lipid molecules, large protein molecules are very challenging to image and consequently demand higher instrumental performance (e.g., ionization efficiency, mass range, and sensitivity). In a similar manner to the ESI technique, nano-DESI tends to generate multiply charged molecular ions, which endows it with a significant advantage when imaging large protein molecules. Recent years have witnessed important nano-DESI-MSI progress for studying protein-ligand interactions and identifying and imaging endogenous proteoforms. In summary, this article focuses on nano-DESI research progress in terms of ion-source development, lipid-structure analysis, and spatial proteomics over the past three years and discusses key challenges that need to be addressed in the field.

Articles

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Impact of arsenic exposure on the hepatic metabolic molecular network in obese pregnant mice using metabolomics and proteomics CAI Lijing, WANG Yan, TAN Junfeng, ZHOU Haixia, LIANG Shijia, WU Yan, ZHANG Jie 2025, 43 (1):  50-59.  DOI: 10.3724/SP.J.1123.2024.05028 Abstract ( 52 )   HTML ( 2 )   PDF (6006KB) ( 35 )   Arsenic is a ubiquitous environmental toxin that can affect normal physiological processes. Although the health impacts of arsenic have been investigated, its influence on hepatic metabolism in obese pregnant women and the underlying mechanisms remain unclear. Multi-omics analysis, including metabolomics and proteomics, can improve the understanding of arsenic-induced hepatotoxicity in obese pregnant women. This study aimed to investigate the adverse effects of gestational arsenic exposure on hepatic metabolism in high-fat-diet-induced obese pregnant mice. Following arsenic exposure during pregnancy, the liver tissue was evaluated comprehensively using metabolomics and proteomics techniques combined with pathological and biochemical analyses. Arsenic exposure not only significantly increased lipid accumulation in the livers of obese pregnant mice but also elevated inflammatory factors and oxidative stress markers. Specifically, histopathological examination revealed more steatosis, inflammatory cell infiltration, and hepatocyte ballooning in the livers of arsenic-exposed mice than in those of controls. These changes indicate that arsenic exposure exacerbates hepatic lipid accumulation and induces liver damage in the context of obesity. Metabolomic analysis provided further insight into the metabolic-level disruption caused by arsenic exposure. Significant changes were observed in lipid metabolism pathways, particularly the arachidonic acid metabolism pathway. As arachidonic acid and its metabolites play important roles in inflammation and oxidative stress, this pathway may be critical in arsenic-induced hepatotoxicity. Additionally, proteomic analysis showed differences in the expression levels of several key proteins involved in lipid synthesis, oxidative stress, and inflammatory response. Notably, oxidative-stress-related proteins, including glutathione peroxidase 4 (GPX4), were upregulated, suggesting an increased oxidative burden. In summary, there are complex interaction mechanisms among arsenic exposure, inflammatory response, and related lipid metabolism. The integration of metabolomics and proteomics aided in clarifying the molecular alterations induced by arsenic. The results show that arsenic exposure significantly affects hepatic lipid metabolism in obese pregnant mice through multiple metabolic pathways and protein regulatory mechanisms. In addition to providing new insights into the relationship between arsenic exposure and obesity as well as related metabolic diseases, this study can act as a reference for environmental health risk assessment and the formulation of public health policies. This enhanced understanding of the adverse effects of arsenic on hepatic metabolism will contribute to the development of strategies for mitigating the health risks associated with environmental toxins, particularly for vulnerable groups such as obese pregnant women.

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Determination of eight phthalate metabolites in urine of pregnant women and evaluation of neonatal birth outcomes based on solid-phase extraction-high performance liquid chromatography-tandem mass spectrometry WANG Zihao, XU Mengfei, LI Beini, WU Ping, WU Wei 2025, 43 (1):  60-67.  DOI: 10.3724/SP.J.1123.2023.12032 Abstract ( 40 )   HTML ( 7 )   PDF (1343KB) ( 24 )   Phthalates (PAEs) are endocrine-disrupting chemicals that are widely present in everyday life and enter the human body through various pathways. The release of PAEs into the environment through pathways that include leaching, evaporation, abrasion, and the use of personal care products exposes humans to PAEs via ingestion, inhalation, and dermal absorption. Pregnant women, as a particularly vulnerable population, risk adverse newborn growth and development when exposed to PAEs. While the concentrations of PAEs in urine reflect recent exposure levels in humans, urinary levels of phthalate metabolites (mPAEs) are commonly used as biomarkers of internal exposure owing to the relatively short biological half-lives of PAEs (<24 h). In this study, we developed a solid-phase extraction-high performance liquid chromatography-tandem mass spectrometry (SPE-HPLC-MS/MS) method for simultaneously detecting eight mPAEs in the urine of pregnant women. Urine samples were enzymatically hydrolyzed with β-glucosidase and then purified using the Bond Elut Plexa SPE column, with subsequent elution, concentration, and redissolved performed prior to HPLC-MS/MS. Separation was achieved using an Agilent Eclipse Plus C18 column (100 mm×3 mm, 3.5 μm), with gradient elution performed using 0.1% acetic acid aqueous solution and 0.1% acetic acid acetonitrile as mobile phases. Multiple reaction monitoring (MRM) mode was used for detection, with quantification performed using the internal-standard method. Good linearities were obtained in the range of 0.1-200 ng/mL for the eight mPAEs, with limits of detection (LODs) and quantification (LOQs) of 0.015-0.048 and 0.050-0.160 ng/mL, respectively. The eight mPAEs exhibited recoveries of 80.2%-99.7% at three spiked levels (1, 10, and 50 ng/mL). This method was subsequently used to analyze the eight mPAEs levels in urine samples of 497 pregnant women from the Ezhou Maternity and Child Health Care Hospital. The participants exhibited widespread exposure to PAEs, with monobutyl phthalate (MBP) showing the highest median level of 104.46 ng/mL, and monobenzyl phthalate (MBzP) showing the lowest (0.22 ng/mL). In addition, this study assessed neonatal birth outcomes. Linear regression modeling revealed that gestational age decreased by 0.11 weeks (95% confidence interval (CI): -0.18--0.03) for every natural-log (ln) increase in the level of monoethyl phthalate (MEP) in urine samples of pregnant woman. Moreover, the birth weight decreased by 39.28 g (95% CI: -76.48--2.09) and 39.62 g (95% CI: -73.73--5.52), for every ln increase in mono(2-ethyl-5-oxohexyl) phthalate (MEOHP) and mono(2-ethylhexyl) phthalate (MECPP) levels, respectively. The developed method is characterized by its simplicity, low LODs, high accuracy, and precision. This study provides clear evidence that PAE exposure during pregnancy negatively affects newborn growth and development by measuring the levels of eight mPAEs in the urine of pregnant women and linking these findings to neonatal outcomes. Further large-scale cohort studies are needed to validate these findings, along with mechanistic studies using animal models or in-vitro systems that elucidate the biological pathways through which mPAEs contribute to adverse birth outcomes.

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Determination of 12 halogenated organic pollutants in edible fish by ultra performance liquid chromatography-high resolution mass spectrometry combined with ultrasound-assisted extraction and gel permeation chromatography purification ZHU Yizhe, ZHENG Ruifen, FAN Zihao, LIU Ling, YE Jingyao, WANG Kai, TANG Caiming 2025, 43 (1):  68-77.  DOI: 10.3724/SP.J.1123.2023.12028 Abstract ( 91 )   HTML ( 10 )   PDF (1480KB) ( 63 )   Halogenated organic pollutants (HOPs) have attracted considerable attention owing to their persistence, bioaccumulation, and toxicity. The development of methods to detect HOPs in fish is challenging owing to the compositional complexity of fish matrices, which contain high levels of lipids and relatively low concentrations of HOPs. In addition, the lipophilicity of most HOPs renders their extraction difficult. Moreover, the simultaneous determination of multiple HOPs to achieve the high-throughput screening of these analytes is complex. In this study, a reliable and efficient pretreatment method based on ultrasound-assisted extraction, gel permeation chromatography purification, and ultra performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS) was developed for the determination of 12 HOPs in edible fish. The procedures of sample extraction and purification and LC-HRMS detection parameters were optimized to improve the performance of the method. Fresh fish samples were thoroughly rinsed with water, and non-edible parts, including the skin, bones, and phosphorus, were removed. The fish were weighed, cut into small pieces, and vacuum freeze-dried for 48 h. Subsequently, a freeze grinder was used to grind the dried fish into a fine powder. Exactly 2 g of the fish powder was weighed, fortified with isotope-labeled internal standards of the HOPs, and allowed to stand for 5 min. Methanol-acetonitrile (1∶1, v/v) was then added, followed by vortex mixing and ultrasonication. After centrifugation, the supernatant was transferred to a fresh tube. The extraction process was repeated twice and all extracts were combined. The extract was evaporated under a gentle nitrogen flow and redissolved in a mixture of ethyl acetate-cyclohexane (1∶1, v/v). The sample mixture was cleaned using gel permeation chromatography, and the eluate was collected and concentrated under a nitrogen flow. Sample residuals were reconstituted with water-methanol (1∶1, v/v) prior to instrumental analysis. Chromatographic separation was performed using an ACQUITY UPLC BEH C18 column (100 mm×2.1 mm, 1.7 μm). Water containing 2 mmol/L NH4Ac and acetonitrile were used as the mobile phases, and an optimized gradient elution program was applied. Isotope dilution and an internal standard method were used to quantify the HOPs. An electrospray ionization source operated in negative mode was applied to ionize the HOPs, and a full scan together with data-dependent acquisition (DDA) was applied for HRMS. Excellent linearities (R2>0.99) were obtained for all HOPs in the quantification range of 1.0-1000.0 ng/mL. The limits of quantification were 0.5 ng/g. The analytical method was validated using pooled fish samples fortified with HOP standards (4, 40, and 400 ng/g). The recoveries of the HOPs were in the range of 67.6%-133.8%, and the corresponding RSDs were 0.5%-15.6%. A total of 27 commercially available fish samples were analyzed using the developed method, and the results revealed the presence of HOPs in the fish, indicating the practicability of the method for real-world samples. The developed method is rapid, accurate, precise, and suitable for detecting HOPs in fish. This study provides a useful approach for environmental monitoring and food safety assurance by enabling the accurate and efficient analysis of HOPs in commonly consumed fish. Given increasing global concerns over HOPs, the method developed in this study will provide practical technical support for consumers aiming to reduce their exposure to and the adverse impacts of HOPs via fish.

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Solid-phase extraction coupled with high performance liquid chromatography-triple quadrupole mass spectrometry for simultaneous determination of seven coumarins in water samples from drinking water treatment plants JIAO Wenmei, YANG Jingming, XU Ce, GAO Fukang, SHEN Luyao, YUAN Yubo, GUO Zhifen, HUANG Guang 2025, 43 (1):  78-86.  DOI: 10.3724/SP.J.1123.2024.06014 Abstract ( 42 )   HTML ( 5 )   PDF (1076KB) ( 31 )   Chlorinated coumarins, which are as cytotoxic as highly toxic halobenzoquinones toward CHO-K1 cells, have recently been identified as disinfection byproducts in drinking water disinfection processes. Therefore, detecting coumarins in water samples collected at various stages from drinking water treatment plants helps assess the formation of chlorinated coumarins in drinking water. Hence, a simple, rapid, accurate, and sensitive method for quantifying coumarins in water samples is required. In this study, a method was developed based on solid-phase extraction coupled with high performance liquid chromatography-triple-quadrupole mass spectrometry for analyzing seven coumarins in water samples from drinking water treatment plants, including 6,7-dihydroxycoumarin, 7-hydroxycoumarin, 6-hydroxy-4-methylcoumarin, 8-chloro-7-hydroxycoumarin, coumarin, 7-chloro-6-hydroxy-4-methylcoumarin, and 3,8-dichloro-7-hydroxycoumarin. Sample pretreatment involved solid-phase extraction using HLB columns, followed by elution with water and methanol, each containing 0.25% formic acid. The extracted solution was separated via gradient elution using a Phenomenex Luna C18 column (100 mm×2.0 mm, 3 mm) with 0.1% formic acid aqueous solution and methanol as the mobile phases, with analytes detected by triple-quadrupole mass spectrometry equipped with electrospray ionization source in multiple reaction monitoring mode. The matrix effect, precision, and accuracy of the developed method were investigated using raw and treated water as matrices. Matrix effects of 0.84-1.12 were recorded for the detection of 6,7-dihydroxycoumarin, 7-hydroxycoumarin, 6-hydroxy-4-methylcoumarin, and coumarin in raw water, while values of 0.67-0.70 were recorded for 8-chloro-7-hydroxycoumarin, 7-chloro-6-hydroxy-4-methylcoumarin, and 3,8-dichloro-7-hydroxycoumarin in finished water. The three chlorinated coumarins exhibited matrix effects above 0.80 after the finished water matrix had been diluted four times. These results suggest that only simple solid-phase extraction or sample dilution is required to accurately determine the seven coumarins in drinking water from treatment plants. In addition, these coumarins exhibited good linear relationships at their respective mass concentrations. The precision and accuracy of the method were evaluated using raw and treated water as matrices. The seven coumarins exhibited good linearities by triple-quadrupole mass spectrometry in a certain range, with correlation coefficients (r) greater than 0.99 and method detection limits (MDLs) of 0.67-1.12 ng/L. The seven coumarins exhibited recoveries of 61.4%-91.5% at three spiked levels (20, 50, 100 ng/L) with relative standard deviations (RSDs, n=6)≤11.2%. The developed method can be used to analyze water samples from various treatment stages of a drinking-water treatment plant. 7-Hydroxycoumarin, 6,7-dihydroxycoumarin, and coumarin were detected at levels of 0.21-27.9 ng/L in 100% of the samples, while 6-hydroxy-4-methylcoumarin was not detected in raw water, post-coagulated water, and post-carbon-filtered water, but was found in sand-filtered water and finished water, with higher levels recorded for the latter (4.69 ng/L) than the former (1.79 ng/L). 8-Chloro-7-hydroxycoumarin was only detected in treated water (0.07 ng/L). This method is highly precise and accurate, provides results in short analysis times, and can be used to effectively monitor coumarins in real water samples and assess their removal during drinking-water treatment.

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Construction of a 17β-estradiol sensor based on a magnetic graphene oxide/aptamer separating material JIN Xinyu, CHEN Leyuan, LIU Yanna, XIE Wenjing, PENG Hanyong 2025, 43 (1):  87-95.  DOI: 10.3724/SP.J.1123.2024.06009 Abstract ( 27 )   HTML ( 5 )   PDF (3479KB) ( 14 )   17β-Estradiol (E2) is a natural steroidal estrogen essential for a variety of physiological functions in organisms. However, external E2, which is renowned for its potent biological effects, is also considered to be an endocrine-disrupting compound (EDC) capable of disturbing the normal operation of the endocrine system, even at nanogram-per-liter (ng/L) concentrations. Studies have revealed that medical and livestock wastewater can be contaminated with E2, which poses potential risks to human health. Currently, the primary method for detecting E2 relies on liquid chromatography-mass spectrometry, which is limited with regard to on-site or large-scale sample testing due to instrumental constraints. Herein, we developed a magnetic graphene oxide (MGO)/aptamer separating material. The MGO was synthesized by creating a water-in-oil microemulsion at 90 ℃, an agarose hydrogel to load the Fe3O4 nanoparticles, and layered graphene oxide (GO). In contrast to conventional methods, such as chemical co-precipitation and solvothermal approaches, this method is more time-efficient and does not require high temperature or pressure. Moreover, the use of a physical encapsulation technique for enwrapping the Fe3O4 nanoparticles and layered GO eliminates the need for chemical modification. This approach reduces the use of harmful chemicals, ensures complete loading, and results in highly efficient encapsulation. The MGO was characterized using Fourier-transform infrared (FT-IR) spectroscopy and transmission electron microscopy (TEM), as well as dynamic light scattering (DLS) and Zeta potential analyses, which revealed that the Fe3O4 nanoparticles had been successfully loaded onto the GO to produce MGO particles mainly around 5 μm in size. Additionally, this study demonstrated that the aqueous MGO dispersion is highly stable. This substance was used to develop a fluorescent biosensor that uses a “turn-on” mechanism to rapidly and highly sensitively detect E2. MGO is capable of adsorbing a fluorescently labeled E2 aptamer (FAM-Apt) in solution, resulting in fluorescence quenching through fluorescence resonance energy transfer (FRET) between the fluorescent group and graphene. However, E2 preferentially binds to FAM-Apt, resulting in the FAM-Apt separating from the MGO in the presence of E2, thereby restoring fluorescence. The developed biosensor exhibits a robust linear correlation between relative fluorescence intensity and E2 mass concentration in the 1-1000 ng/mL range, and boasts a low detection threshold of 1 ng/mL. The use of MGO as an absorbent and fluorescence quencher led to an E2-detection limit that is two orders of magnitude lower than that of a GO-based sensor. This biosensor also outperforms other aptamer-based systems in terms of detection time, linear range, and sensitivity; it also demonstrates remarkable resilience toward various interfering ions and exhibits strong selectivity among structurally similar estrogen analogs. A range of ions commonly present in water samples were introduced into the reaction system at specific concentrations to gauge the impact of interfering ions on sensor performance. With the exception of Fe3+ ions at 0.3 mg/L, which led to a lower fluorescence intensity, interfering ions were found to exhibit minimal effects. Biosensor specificity and selectivity were further scrutinized by introducing four estrogenic disruptors, including estriol (E3), 17β-ethynylestradiol (EE2), estrone (E1), and bisphenol A (BPA), each at a mass concentration of 1 μg/mL under the same reaction conditions used to detect E2. The recovered relative fluorescence-signal values for E1 and E3 were determined to be 33% and 23% that of E2, respectively, while EE2 and BPA hardly elicited any fluorescence signal recovery, thereby highlighting the ability of the biosensor to precisely detect E2 with minimal interference from estrogen analogs. The efficacy of the MGO-FAM-Apt biosensor was subsequently validated by testing river-water samples containing known quantities of added E2, which yielded recoveries of between 91.0% and 110.0%, thereby affirming the reliability of this biosensor for use in practical applications. The developed sensor may be somewhat limited compared to liquid chromatography-high-resolution mass spectrometry in detection limit, but the developed biosensor is cost-effective, detects rapidly, and is capable of simultaneously analyzing multiple samples, making it suitable for on-site or large-scale E2 testing of environmental water samples.

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Evaluation of the toxicity of perfluorooctanoic acid toward human colorectal cancer cells using multi-dimensional approaches ZHANG Ruijia, LIN Yingshi, TU Lanyin, CHEN Zitong, ZHANG Weiwei, LUAN Tiangang, CHEN Baowei 2025, 43 (1):  96-103.  DOI: 10.3724/SP.J.1123.2024.05022 Abstract ( 29 )   HTML ( 3 )   PDF (2838KB) ( 11 )   While human exposure to perfluorooctanoic acid (PFOA) can lead to ulcerative colitis, the molecular mechanisms responsible for PFOA-induced intestinal toxicity are unclear. Herein, we examined the toxicity of PFOA toward human colorectal cancer cells (HCT116) from three dimensions: the cytotoxic phenotype, cell respiration, and transcription levels of metabolism-related genes. Formazan was used to assess how PFOA exposure affects HCT116-cell relative viability, after which the mitochondrial respiratory activities of these cells were determined by analyzing extracellular flux. The quantitative real-time polymerase chain reaction (qPCR) method was used to detect metabolism-related gene expression levels. The cytotoxicity assay revealed that the HCT116 showed significantly inhibited relative activities compared to those of the control when exposed to 300 μmol/L PFOA for 48 h (p<0.01), with most cells retained at the G0/G1 stage. In contrast, the mitochondrial respiratory activities of the HCT116 were promoted by concentrations of PFOA as low as 50 μmol/L. Two genes related to cellular metabolism (dipeptidase 1 (DPEP1) and sphingosine kinase 1 (SPHK1)) were found to be related to the PFOA-promoted formation of ulcerative colitis using our self-developed Metabolic Gene and Pathway Query software and Comparative Toxicogenomics Database (CTD). The qPCR studies revealed that DPEP1 and SPHK1 expression levels were enhanced by 8-10 times in HCT116 exposed to 300 μmol/L PFOA relative to the control, whereas this trend was not observed for HCT116 exposed to 50 μmol/L PFOA. Collectively, these results suggest that the respiratory activity of cellular mitochondria may serve as an index for determining the interference effects associated with PFOA and that metabolic pathways mediated by DPEP1 and SPHK1 may be involved in the development of PFOA-induced ulcerative colitis. Future studies should investigate the relationships between changes in metabolism-related genes (DPEP1 and SPHK1) and the mitochondrial respiratory activities of intestinal cells, and verify the roles played by the DPEP1 and SPHK1 genes in PFOA-induced intestinal inflammation using in-vivo models.