Polychlorinated biphenyls （PCBs） pose serious threats to the environment and human health because they are among the most common and persistent organic pollutants globally. In this study， six PCBs were extracted from environmental water samples using multiwalled carbon nanotubes （MWCNTs） on polystyrene （PS） microspheres as the solid-phase microextraction （SPME） coating material for gas chromatography-tandem mass spectrometry （GC-MS/MS）. This coating material is highly stable and exhibited a high extraction efficiency. 2，2′，5，5′-Tetrachlorobiphenyl （PCB-52）， 2，2′，4，5，5′-pentachlorobiphenyl （PCB-101）， 2，3′，4， 4′，5-pentachlorobiphenyl （PCB-118）， 2，2′，3，4，4′，5′-hexachlorobiphenyl （PCB-138）， 2，2′，4，4′，5，5′-hexachlorobiphenyl （PCB-153） and 2，2′，3，4，4′，5，5′-heptachlorobiphenyl （PCB-180） were chosen as target analytes. The main extraction factors were optimized using a single-factor optimization method， which led to the following optimum extraction conditions： adsorption time， 50 min； agitation speed， 600 r/min； pH， 6； NaCl concentration， 1.5 mol/L； desorption temperature， 280 °C； and desorption time， 4 min. GC coupled with triple quadrupole mass spectrometry was used to quantify PCBs in water samples. The chromatographic separation system was equipped with a TG-5 SILMS column （30 m×0.25 mm×0.25 μm）， with electron impact ionization and multi-reaction monitoring modes used during mass spectrometry. Five batches of MWCNT@PS were used as SPME coating materials， which were determined to have relative standard deviations （RSD） of less than 8.8% for the six PCBs. The reusability of the MWCNT@PS coating was also investigated； RSD of the recoveries of 2.8%–9.3% were obtained after ten SPME cycles with the same coating. These results reveal that the MWCNT@PS coating materials are highly stable and reusable in SPME applications， with good results obtained under the optimal conditions. The established method exhibited linearity in the range of 0.03–1 000 ng/L for PCB-52 and PCB101， 0.07–1 000 ng/L for PCB118， PCB138， and PCB 153， and 0.10–1 000 ng/L for PCB-180， with correlation coefficients of 0.993-0.998. Limits of detection and quantification （LODs and LOQs， respectively） of 0.01–0.03 and 0.03–0.10 ng/L were determined for the developed method. The intra- and inter-day precisions exhibited RSDs of 1.64%–8.16% and 2.83%–8.41%， respectively， at 2 ng/L， 3.31%–7.19% and 3.79%–9.12%， respectively， at 10 ng/L， and 2.70%–9.38% and 4.04%–8.56%， respectively， at 100 ng/L. The established method was used to determine six PCBs in barreled drinking water， rainwater， and three environmental river water samples. No PCBs were found in barreled drinking water， rain water and river water. Satisfactory recoveries of 82.4%-113.2% were achieved at low， medium， and high levels. Accordingly， the MWCNT@PS-composite-coating-material-based SPME-GC-MS/MS method is accurate and effective. This study revealed that MWCNT@PS composites provide a good avenue for the rapid and sensitive detection of PCBs in water samples.

Tetrodotoxin （TTX） is a powerful small-molecule neurotoxin primarily produced by specific marine endosymbiotic bacteria and can be enriched during symbiosis with aquatic organisms such as pufferfish， gastropods， and blue-ringed octopuses. TTX prevents sodium ions from entering nerve cells， which affects neuromuscular conduction and leads to progressive paralysis and even death due to respiratory failure. Poisoning ascribable to the ingestion of TTX-containing seafood has occurred occasionally in some coastal areas of China. The early identification of toxins and the administration of symptomatic detoxification therapies can improve the resuscitation success rates of poisoned patients. The concentration of TTX in clinical biological samples reflects the degree of patient poisoning and their prognosis. A method was established for the determination of the TTX in poisoned biological samples by two-dimensional liquid chromatography-tandem mass spectrometry （2D-LC-MS/MS）. A human plasma or urine sample （100 μL） was accurately pipetted into a 2-mL centrifuge tube， sequentially added a 10 mg/L kasugamycin solution （10 μL； internal standard）， ultrapure water （150 μL）， and 0.5% （v/v） acetic acid in acetonitrile （250 μL） as the extraction solvent， after which the mixture was subjected to vortex mixing at 2 200 r/min for 10 min and centrifugation for 10 min at 15 000 r/min and 4 ℃. The supernatant was roughly separated using a first-dimensional reverse-phase C₁₈ column （Hypersil Gold C₁₈， 50 mm×2.1 mm， 1.9 μm）. The target fraction was then transferred to a hydrophilic liquid chromatography column （Acquity UPLC BEH Amide， 150 mm×3.0 mm， 1.7 μm） via a six-way switching valve for second-dimensional separation and analysis using positive electrospray ionization and selected reaction monitoring （SRM） modes. Kasugamycin served as the internal standard for TTX quantitation， using matrix-matched calibration combined with the internal standard method. TTX exhibited good linearity in the 0.2-40.0 μg/L range （equivalent to 1.0-200.0 μg/L in biological samples）， with a correlation coefficient exceeding 0.999 4. The TTX in human plasma and urine samples exhibited matrix effects of 80.9% and 98.9%， respectively， with LODs and LOQs of 0.3 and 1.0 μg/L， respectively， determined for both sample types， based on three- and ten-times signal-to-noise ratios， respectively. The TTX in human plasma and urine exhibited intra-day recoveries of 84.4%–98.4% and 84.4%–96.9%， respectively， with inter-day recoveries of 87.7%–96.2% and 84.8%–95.7%， respectively， at spiked levels of 2.0， 10.0， 50.0， and 200.0 μg/L. Intra-day relative standard deviations （RSDs） of 3.2%–7.2% and 2.9%–5.7% were recorded for TTX in human plasma and urine， respectively， with inter-day RSDs of 2.3%–3.2% and 1.0%–7.5%， respectively. The intra-day and inter-day RSDs of both sample types were determined to be lower than 7.5%. The method is accurate， fast， avoids complicated pretreatment steps， and was successfully used to detect TTX in food-poisoning scenarios.

Experimental teaching， serving as a bridge between theoretical knowledge and practical competence， can deepen students’ understanding of theoretical concepts， and enhance their ability to solve complex problems， thereby playing a pivotal role in cultivating elite chemistry talents for the national innovation system. By understanding the laws of higher education development and innovative talent growth， the Chemistry Experiment Teaching Center of the College of Sciences at Northeastern University has innovatively proposed a closed-loop teaching model： “Construction Supports Competitions-Competitions Nurture Teaching-Teaching Promotes Learning”， aiming at the problem of difficult barrier between scientific research and pedagogy in talent development. This model is based on the requirements for cultivating top innovative talents， leveraging the practical feedback of disciplinary competitions， and creating a dynamic feedback mechanism of “Competition Incubation→Teaching Transformation→Competency Feedback”. Taking the award-winning project “Micro-Plasma Emission Spectrometer Setup and Trace Element Analysis Experiment” from the Chemistry Innovation Design Competition as an example， this study demonstrates the model’s breakthrough in traditional experimental teaching. Through a 4-class-hour experimental course， students independently construct a dielectric barrier discharge （DBD） micro atomic emission spectroscopy device， combined with hydride generation （HG） introduction technology to complete trace arsenic detection. The method showed a good linear relationship in the mass concentration range of 20-500 μg/L， with a coefficient of determination （R²） of 0.997. Teaching practice shows that students deepened their understanding of principles and made the instrument structure transparent through hands-on construction， promoting the improvement of teaching quality and providing a scalable innovative paradigm for the “high-order， innovative， and challenging” curriculum reform.

A research-project-based open instrumental-analysis experiment was designed for undergraduate teaching led by the attributes of an environmental science major. In this experiment， porous monolithic fibers are in-situ synthesized from 9-vinylanthracene and styrene （as a monomer mixture） based on the molecular characteristics of studied polycyclic aromatic hydrocarbons （PAHs）， and then used as an extractant for solid-phase microextraction （SPME）. A method for reliably monitoring PAHs in environmental water samples was developed by combining SPME with high performance liquid chromatography （HPLC）. Students designed and constructed a complete experimental instrumental-analysis process， which included preparing and characterizing the monolith fibers， optimizing the SPME conditions， preparing environmental water samples， and analysis by HPLC. Guided by teachers， undergraduates learned relevant knowledge prior to performing the experiment， improved their operating skills during the experiment， analyzed data， and wrote research reports during the latter stage of the course. Undergraduates' interest is stimulated by completing the experiment， while scientific thinking， analysis， and problem-solving abilities are concurrently improved and cultivated. The present course also lays the foundation for cultivating future high-quality environmental-science talents.

Organophosphate triesters （tri-OPEs） are synthetic phosphate derivatives that are primarily used as flame retardants and plasticizers. Tri-OPEs have become significant aquatic contaminants owing to their large production volumes and wide range of applications. Organophosphate diesters （di-OPEs） are closely related to tri-OPEs. Aside from emissions resulting from the production and usage of di-OPEs themselves， tri-OPEs can become transformed into di-OPEs， which also provides a significant source of this environmental contaminant. The physicochemical properties of a di-OPE depend significantly on its structure， which provides challenges for their detection and analysis， including low extraction efficiencies， chromatographic separation difficulties， and a lack of highly sensitive quantitative methods for their analysis. An increasing number of studies have found that di-OPEs are present in industrial/domestic wastewater， surface water， and drinking water， with some concentrations in surface water and tap water close to or even higher than those of the corresponding tri-OPEs. Additionally， certain di-OPEs are somewhat more toxic than the corresponding tri-OPEs； hence， awareness that di-OPEs are present in aquatic environments has raised widespread concern. This review first systematically outlines the physicochemical properties of common di-OPEs and their potential sources based on previous research into di-OPEs in water matrices. In addition， the use of solid phase extraction （SPE） technology to extract， enrich， and purify di-OPEs from water matrices is summarized， while the advantages and limitations of SPE methodologies are critically evaluated. Furthermore， the use and distinctive features of reverse-phase chromatography， ion-pair reverse-phase chromatography， and hydrophilic interaction liquid chromatography （HILIC） for the chromatographic separation of di-OPEs are comprehensively summarized and compared. At the same time， advances in the quantitative analysis of di-OPEs using liquid chromatography-tandem triple quadrupole mass spectrometry （LC-MS/MS） and liquid chromatography-high-resolution mass spectrometry （LC-HRMS） are reviewed. Finally， in terms of efficient collection of water samples and high-throughput pretreatment of di-OPEs in water matrices， the prospect of developing novel sampling and on-site enrichment technologies for new pollutants in water matrices based on the principle of dispersed solid phase extraction is proposed. Additionally， the prospect of using liquid chromatography tandem high-resolution mass spectrometry for high-throughput screening and high-sensitivity detection of di-OPEs and unknown transformation products of tri-OPEs has been proposed.

Blood， which forms part of the systemic circulatory system， contains proteins from various tissues and organs. Hence， blood samples are ideal vehicles for studying diseases and physiological states. Plasma is an important component of blood and is essential for clinical proteomics research. Plasma contains rich physiological and pathological information； consequently， it is an ideal medium for discovering disease-related biomarkers. Protein N-glycosylation is a key post-translational modification route. This route is widely involved in biological processes such as intercellular communication， immune regulation， and signal transduction. Changes resulting from aberrant N-glycosylation are closely associated with various pathological conditions， including autoimmune and neurodegenerative diseases and tumors. Hence， N-glycosylation proteomics is highly valuable during biomarker and drug-target development. However， efficiently enriching N-glycopeptides in biological samples before detection by mass spectrometry （MS） is difficult. This is because the highly abundant unmodified peptides result in signal suppression. Consequently， achieving deep N-glycoproteomic coverage is a key challenge， particularly for trace plasma samples， for which in-depth studies are currently lacking. In this study， we developed a strategy for comprehensively profiling trace N-glycopeptides in plasma. This includes an efficient enrichment method in combination with highly sensitive MS. The developed approach integrates glycopeptide enrichment using advanced hydrophilic interaction liquid chromatography （HILIC） with state-of-the-art MS platforms. This significantly enhances detection depth and sensitivity during N-glycosylation analysis using minimal plasma volumes. Selectivity and efficiency during N-glycopeptide enrichment were maximized by systematically optimizing key HILIC-packed stationary-phase parameters. These parameters include chemical composition， pore size， and surface modification. Additionally， the elution gradient was fine-tuned to improve glycopeptide recovery. This optimization process delivered high N-glycopeptide specificity， even in complex plasma matrices. To overcome the limitations of single-platform MS， we implemented a complementary dual-platform strategy. This strategy combines the high-speed， high-resolution capabilities of the Tims TOF Pro 2 instrument with the ultra-high mass accuracy and resolution of the Orbitrap Lumos spectrometer. The former instrument facilitates the rapid and sensitive identification of glycopeptides， particularly for low-abundance species. It exploits the trapped ion mobility spectrometry （TIMS） and parallel accumulated sequential fragmentation （PASEF） technology. The Orbitrap Lumos provides exceptional mass accuracy and high-resolution MS/MS spectra that enable confident glycopeptide structural characterization. This synergistic approach significantly expands the N-glycopeptide identification depth and ensures comprehensive glycosylation-site and glycan-composition coverage. The developed optimized workflow successfully identified 2 962 intact N-glycopeptides using only 20 μg of plasma peptides （equivalent to 0.5 μL of whole plasma）. This set a new benchmark for sensitivity in the micro-volume plasma glycoproteome field. This achievement addresses a critical gap， where conventional methods typically require much larger sample volumes. This limits their applicability to clinical and precision medicine settings where sample availability is restricted. The developed platform provides a robust and reliable analytical framework for plasma N-glycoproteomics with significant implications for precision medicine. This method facilitates large-scale clinical studies by enabling highly sensitive glycopeptide profiling from very small plasma volumes. This included the longitudinal monitoring of disease progression and therapeutic responses. Furthermore， it offers a powerful tool for discovering novel N-glycosylation-based biomarkers for use in early disease diagnosis， prognosis， and personalized treatment strategies. In summary， this study advances the technical capabilities of plasma N-glycoproteomics. Additionally， it facilitates the broader use of plasma N-glycoproteomics in biomedical research and clinical diagnostics.

Perfluorinated and polyfluoroalkyl compounds （PFASs） represent a category of synthetic chemicals renowned for their environmental persistence. Owing to their hydrophobic， oleophobic， and high-temperature-resistant properties， PFASs are extensively utilized in industrial， agricultural， and civilian sectors， including applications in leather， textiles， flame-retardant materials， lubricants， and coatings， among others. PFASs can accumulate within the human body， exhibiting multi-organ toxicity. Continuous monitoring of PFASs with ambiguous toxicity profiles is vital for evaluating human exposure and associated health risks. Consequently， the establishment of a high-throughput and highly sensitive detection method is of paramount importance for accurately assessing the exposure levels of PFASs in the human body. In this study， a commercial high-throughput HMR-Lipid 96-well solid-phase extraction plate was adopted， combined with high performance liquid chromatography-tandem mass spectrometry （HPLC-MS/MS）， to establish a simple， efficient method that can simultaneously quantitatively detect 26 PFASs in human serum. Serum samples were extracted using the HMR-lipid 96-well solid-phase extraction plate. The Phenomenex C₁₈ chromatography column （250 mm×4.6 mm， 5 μm） was used as the capture column and connected between the liquid chromatography mixer and the autosampler to avoid high background pollution. The target compounds were separated by the Accucore C₁₈ chromatography column （100 mm×2.4 mm， 2.6 μm） and analyzed using the electrospray ionization with negative ion scanning mode and multiple reaction monitoring （MRM） mode. The methodological validation results indicated that the 26 PFASs had good linear relationships within the range of 0.2-100 ng/mL， with correlation coefficients （r） of 0.995 1-0.999 9. The limits of detection （LODs） and quantification （LOQs） were 0.01-0.15 ng/mL and 0.02-0.47 ng/mL， respectively. At three spiked levels of low， medium and high， the recoveries of the 26 PFASs ranged from 80.1% to 119.5%， and the relative standard deviations （RSDs） ranged from 0.5% to 11.9%. This method has the advantages of high sensitivity， good accuracy， simple operation， fast extraction speed， low reagent consumption and small sample volume required. It is suitable for large-scale population biological monitoring and provides a scientific method support for accurately assessing the exposure of PFASs in the human body and its potential health risks.

Bisphenol A （BPA） and its analogs are collectively termed bisphenol compounds （BPs）， which are predominantly utilized in the manufacturing of polycarbonate plastics and epoxy resins. BPs are ubiquitous in diverse environmental matrices， human tissues， and metabolic products. Extensive research has demonstrated that BPs exert adverse effects on the nervous， reproductive， immune， and metabolic systems. After exposure in humans， BPs are primarily excreted in urine. Consequently， the development of efficient and robust analytical methods for BPs quantification in urine is essential for assessing population exposure levels. In this study， solid supported liquid-liquid extraction （SLE） was combined with ultra-high performance liquid chromatography-tandem mass spectrometry （UHPLC-MS/MS） technology to establish a high-throughput determination method for 17 BPs in human urine. After enzymatic hydrolysis treatment of the samples， the steps of fully automatic SLE purification， nitrogen blowing concentration and redissolution were carried out successively. Separation was performed using a CAPCELL PAK ADME chromatography column （100 mm×2.1 mm， 2 μm）， and gradient elution was carried out with 0.05 mmol/L ammonium fluoride aqueous solution and 0.05 mmol/L ammonium fluoride methanol solution as the mobile phases. MS detection was carried out using the electrospray ionization （ESI） negative ion scanning mode under the multi-reaction monitoring （MRM） mode. Qualitative analysis was conducted based on retention time and ion abundance ratio， and quantitative analysis was performed using the internal standard method. Under the optimized conditions， 17 BPs can be effectively separated. The linear relationships of the 17 BPs within the corresponding mass concentration ranges were good， and the correlation coefficients （r） were ≥0.998 6， the limits of detection （LODs） and quantification （LOQ） were 0.002-0.489 μg/L and 0.005-0.986 μg/L， respectively. Children’s mixed urine samples with low background content were selected as the matrix， and then spiked recovery tests were conducted at three spiked levels （low， medium and high）. The results showed that the recoveries of 17 BPs were 61.1%-121.7%， the intra-day RSDs were 1.3%-11.2%， and the inter-day RSDs were 3.7%-19.0%. This method was used to determine 50 random urine samples， and the results showed that a total of 11 BPs were detected. Among them， bisphenol S （BPS） and BPA had the highest detection rates， which were 98.0% and 86.0% respectively， and the median detection levels were 0.075 μg/L and 0.829 μg/L respectively. This method is simple to operate， sensitive and reliable. It is suitable for the rapid quantitative analysis of 17 BPs in human urine and can provide effective technical support for the risk assessment of BPs exposure in the population.

An ultra performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS） method was established to determine N-（1，3-dimethylbutyl）-N′-phenyl-p-phenylenediamine-quinone （6PPD-Q） in human urine and dust in order to understand the internal and external exposure levels in humans. The sample preparation conditions were systematically investigated and the chromatographic conditions and MS parameters were optimized. Briefly， internal standard ¹³C₆-6PPD-Q （0.1 ng） was added to a urine sample. Glutathione and NaCl were added after equilibration for 30 min. The mixture was then twice ultrasonically extracted with ethyl acetate. Internal standard ¹³C₆-6PPD-Q （1.0 ng） was also added to a dust sample and the mixture was twice ultrasonically extracted with n-hexane. The combined organic phases were concentrated to near-dryness and then redissolved for instrumental determination， which was performed on a Phenomenex Kinetex F5 column （100 mm×3 mm， 2.6 μm）， with the target analyte gradient eluted using 10 mmol/L ammonium acetate aqueous solution containing 0.01% formic acid and acetonitrile. Positive electrospray ionization （ESI⁺） and multiple reaction monitoring （MRM） modes were used for identification purposes， and an isotope-labeled internal standard was added for quantification. Good linearities were achieved under the optimized conditions within the 0.01–4.00 and 0.01–20.0 μg/L ranges for urine and dust， respectively， with correlation coefficients of 0.999 9 and 0.999 3， respectively. Limits of detection （LODs） were 0.6 ng/L （urine） and 0.018 ng/g （dust）. Spiked recoveries of 6PPD-Q were 90.3%–94.1% at low， medium， and high spiked levels， with intra-day and inter-day precisions of 0.9%–5.9% and 1.1%–6.3%， respectively. Matrix-effect investigations revealed that 6PPD-Q exhibited weak matrix effects in urine and dust after correction with the isotopic internal standard. The developed method was used to analyze 120 human urine samples， which led to a 6PPD-Q detection frequency of 74.2%， with mass concentrations ranging from <LOD to 13 ng/L， with average and median mass concentrations of 2 and 1 ng/L， respectively. However， 6PPD-Q was detected with a frequency of 100% in 31 indoor dust samples with contents of 1.8–24.9 ng/g， and average and median contents of 5.23 –3.05 ng/g， respectively. The developed method is accurate， reliable， highly sensitive， and it is suitable for the rapid determination of 6PPD-Q in human urine and dust samples.

The consumption of agricultural products has increased in recent years owing to abundant production and improved living standards. Veterinary drugs are highly commercialized and widely used in animal husbandry to ensure animal health and production performance. Moreover， pesticides can become enriched during animal breeding， resulting in animal-derived food pollution through foraging， drinking， and environmental disinfection that can potentially damage human health. Consequently， food-safety issues associated with pesticide and veterinary-drug residues have attracted considerable attention. However， few reports on the multi-residue analysis of livestock and poultry meat using ultra performance liquid chromatography-quadrupole time of flight mass spectrometry （UPLC-Q-TOF/MS） have been published. Therefore， developing high-throughput and efficient screening methods for monitoring various illegal and/or restricted drugs in animal-derived foods is imperative. In this study， we developed a protocol for simultaneously examining seven pesticide and veterinary-drug types that uses an accurate mass-spectral library. UPLC-Q-TOF/MS was then employed to screen 111 such compounds， including quinolones， macrolides， cephalosporins， and antiviral drugs. The developed protocol was subsequently used to establish a method for quantitatively analyzing more than 90 compounds in livestock and poultry meat. The formula， theoretical exact mass， experimental exact mass， and retention time of each analyte were recorded and used for identification purposes. The main factors affecting the response and sensitivity of the method， such as the LC separation conditions （chromatographic column and mobile phases） and MS parameters， were optimized during instrumental analysis. Pork and chicken samples were extracted with an 80% acetonitrile aqueous solution， after which the supernatant was purified using an Oasis PRiME HLB solid-phase extraction column. The 111 target analytes were separated on a Waters HSS T3 analytical chromatographic column （100 mm×2.1 mm， 1.8 μm） after being blown with nitrogen and redissolved， with gradient elution performed using mobile phases composed of 0.1% formic acid aqueous solution and methanol. The analysis process included a flow rate of 0.4 mL/min， a column temperature of 40 ℃， and an injection volume of 5 μL， with positive electrospray ionization （ESI） and time of flight mass spectrometry full scan information-dependent acquisition-product ion （TOF MS-IDA-Product Ion） scanning modes used. The method was validated in terms of linearity， limits of screening and quantification （SDLs and LOQs， respectively）， matrix effects， accuracy， and precision. Quantification was performed using matrix-matched external-standard calibration. All target compounds exhibited good linearities in their corresponding concentration ranges， with all correlation coefficients （r²） above 0.99. The SDLs of all analytes were in the range of 0.5-10 μg/kg， and the proportion of LOQs within the range of 0.5-10 μg/kg were 88.3% and 86.5%， respectively. The compounds quantified in pork and chicken exhibited recoveries of between 60.2% and 100.2%， and 61.1% and 116.7%， respectively， at spiked levels of LOQ， 2×LOQ and 10×LOQ， with relative standard deviations （RSDs） ranging from 1.1% to 13.9% and 1.0% to 14.1%， respectively. Simulated positive samples and commercial livestock and poultry meat samples were screened using an in-house-constructed mass spectrometry database. Commercial samples were screened while enrofloxacin was detected in two pork samples and tilmicosin was detected in one chicken sample， with content in the range of 4.94-29.1 μg/kg. The method developed in this study is advantageous because it involves simple sample processing and is less time consuming than existing methods； consequently， it is suitable for the rapid and high-throughput screening of pesticides and veterinary residues in livestock and poultry meat.