Trace contaminants are toxic and their widespread presence in the environment potentially threatens human health. The levels of these pollutants are often difficult to determine directly using instruments owing to the complexities of environment matrices. Hence, pretreatment steps, such as sample purification and concentration, are key along with various processes that enhance the accuracy and sensitivity of the detection method. To date, researchers have successfully developed a variety of efficient and reliable sample-pretreatment techniques that are based on different principles. Among these, magnetic solid-phase extraction (MSPE) is a rapid and efficient sample-pretreatment technology that is based on the similar solid-phase-extraction (SPE) principle, which mainly enriches target analytes by exploiting their interactions with functional groups on the surfaces of magnetic materials, thereby achieving rapid separation when an external magnetic field is applied. MSPE has been a focus of attention in the environmental-sample-pretreatment, food-analysis, and other fields owing to advantages that include ease of operation, low cost, and high enrichment efficiency. The selection of the magnetic material is key to MSPE process because traditional magnetic materials exhibit certain functionality limitations. Accordingly, designing and synthesizing green and efficient functionalized magnetic materials have become a research focus in this field, with researchers having extensively explored multiple ways of preparing functionalized modified magnetic materials through the introduction of a variety of emerging materials, including metal-organic frameworks (MOFs), covalent organic frameworks (COFs), carbon nanotubes (CNTs), graphene oxide (GO), and other specific functional groups to modify magnetic materials and effectively expanded the applications scope of MSPE. Among these, COFs are porous crystalline materials consisting of light elements (C, N, H, O and B, etc.) linked through covalent bonds. COFs are mainly classified as imine COFs, boronic-acid COFs, triazine COFs, and ketenimine COFs according to bonding type. Moreover, it is worth mentioning that COFs can be synthesized from a number of monomers, and the functional groups exposed on the COF surface can also be used for further modification purposes. COFs are versatile and modifiable; consequently, they have attracted significant research attention, with a series of COF-functionalized magnetic materials having been designed and synthesized. The magnetic COFs (MCOFs) combine the advantages of COFs and magnetic materials. MCOFs are not only endowed with the large specific surface areas, high porosities, and good stabilities that are characteristic of COFs, but also exhibit the rapid separation and reusability characteristics of magnetic material, thereby quickly and efficiently enriching targets through hydrogen bonding, hydrophobicity, π-π stacking, and van der Waals forces, making them ideal sample-pretreatment materials. MCOFs have also been converted into more-versatile functional materials using post-modification strategies. Combining MCOFs with advanced analytical techniques, such as high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) has effectively improved the limits of detection (LODs) for various analytes as well as method accuracy; these techniques have been widely used to enrich and detect trace pollutants. However, some material design and synthesis challenges remain and need to be overcome, despite the promising potential of MCOFs. Future research needs to focus on exploring novel synthetic strategies that reduce experimental costs and improve the functionalities of MCOFs while expanding their applicabilities to broader sample matrices. In this review, we first introduce and discuss the construction and functionalized designs of various MCOF composites, and then summarize their use in applications that include the enrichment and detection of pesticides, endocrine disruptors (EDCs), pharmaceuticals, and personal care products (PPCPs), and finally provide an outlook on future developmental prospects.

Solid-phase microextraction (SPME) is a fast and simple sample preparation technique that enables the enrichment of analytes, and it is used in combination with other detection techniques to provide accurate and sensitive analytical methods. SPME is widely used in environmental monitoring, food safety, life analysis, biomedicine, and other applications. The extractive coating is the core of the SPME technique, and the properties of the extractive coating greatly influence extraction selectivity and efficiency, as well as the enrichment effect. Therefore, the development of new and efficient extractive coating materials remains a hot topic in the analytical chemistry and sample preparation fields. Covalent organic frameworks (COFs) are a kind of porous crystalline network polymer materials formed by covalent bonds. Owing to the advantages of large specific surface area, high porosity, good stability, high designability, simple synthesis and post-modification, etc., it has been widely used in gas adsorption, catalysis, sensing and drug delivery. In recent years, COFs have attracted much attention in the field of sample preparation. A variety of novel COF-based SPME materials had been developed for extracting and enriching various types of analytes through π-π interaction, hydrophilic/hydrophobic interaction, electrostatic adsorption, and hydrogen-bonding, as well as pore effects. In this paper, the research advances of COFs for using in fiber-, in tube-, and membrane-based SPME over the past three years were discussed. Fiber surfaces had been modified with functionalized COFs or COF-hybrid materials for use in SPME through physical coating, in-situ growth, and chemical-bonding approaches. The combination of SPME fiber and chromatographic analysis can be used to detect a variety of analytes such as polycyclic aromatic hydrocarbons, phthalates, polychlorinated biphenyls, and pesticides in environmental and food samples, with good enrichment effects, wide linear ranges, and high sensitivity. Based on in tube-SPME, COFs-based monolithic column and fiber-filled tube as the extraction tubes were combined with high performance liquid chromatography online to develop highly sensitive detection methods for synthetic phenolic antioxidants and bisphenol compounds, respectively. In addition, COFs had also been used in membrane SPME technique, showing high efficiency in the extraction of trace polychlorinated biphenyls in environmental water. Finally, the development trends of COFs in the field of SPME was prospected.

Chemical modifications are widely used in research fields such as quantitative proteomics and interaction analyses. Chemical-modification targets can be roughly divided into four categories, including those that integrate isotope labels for quantification purposes, probe the structures of proteins through covalent labeling or cross-linking, incorporate labels to improve the ionization or dissociation of characteristic peptides in complex mixtures, and affinity-enrich various poorly abundant protein translational modifications (PTMs). A chemical modification reaction needs to be simple and efficient for use in proteomics analysis, and should be performed without any complicated process for preparing the labeling reagent. High reaction specificity, which reduces product complexity, and mild biocompatible reaction conditions are also favored. In addition, modification labels should be compatible with mass spectrometry to prevent interference from ionization and dissociation processes. Pulsed ultraviolet (UV) lasers can produce large amounts of active radical species within a few nanoseconds for use in rapid photochemical-modification processes. Usually, UV lasers with wavelengths greater than 240 nm are used in current in-situ photochemical-modification methods; consequently, special conjugated photoreaction probes need to be designed and oxidants and catalysts added, which reduce the biocompatibility of the reaction. The high single-photon energy of the 193 nm laser is capable of efficiently exciting conventional photo-inert substances in aqueous solution, leading to efficient photochemical peptide modifications. In this study, we developed a new method for photochemically brominating and iodinating enzymatic protein samples extracted from complex tissue with a 193 nm ArF nanosecond pulsed laser, which efficiently brominated tyrosine, histidine, and tryptophan, and iodinated tyrosine and histidine.

Tandem mass spectrometry (MS/MS) can generate fragmentation patterns of ions which can afford diagnostic molecular fingerprints to decipher sequences of biopolymers such as peptides. Peptide fragmentation is commonly implemented using collision-based, electron-based, or photodissociation-based methods. Compared with the most commonly used collision-based methods, ultraviolet photodissociation (UVPD) uses high-energy ultraviolet photons with wavelengths shorter than 200 nm to excite and dissociate ions. Single-pulse excitation can provide the energy required to promote ions into their excited electronic states, with excitation speeds of up to several nanoseconds. Since dissociation may occur directly from the excited states, UVPD spectra can show a wide variety of fragmentation pathways, thereby providing more sequence and structural information. The most commonly used wavelengths are 157, 193, and 266 nm. UVPD has been integrated into high-resolution orbitrap mass spectrometer by adding optical windows and other optics to direct the photons to the analyte ions, and by implementing a triggering method that synchronizes the photoirradiation process with ion-analysis events. The large photoabsorption cross sections of peptides at 193 nm and the resulting high internal energy deposition can generate abundant fragment ions and achieve high sequence coverage. The excellent fragmentation performance offered by 193 nm UVPD of peptides with its high sequence coverage and lack of charge-state dependence, has motivated its use in high-throughput proteomics. Photochemically brominated and iodinated mouse-liver tryptic peptides were further characterized by 193 nm UVPD tandem mass spectrometry with the aim of analyzing their sequences, modification sites, and photodissociation mechanisms. Br and I atoms strongly absorb 193 nm photons; consequently, UVPD can cleave C-Br/C-I bonds at halogenated sites to generate peptide radical ions, with further peptide-backbone fragmentation caused by radical migration. In addition, the combination of 193 nm UVPD with conventional high-energy collision-induced dissociation (HCD) mode improves the identification-reliability of halogenation sites in proteomics. Therefore, integrating photochemical halogenation and 193 nm UVPD can trigger novel radical-dissociation pathways, thereby improving analytical proteomics performance.

Biomarkers for ischemic stroke (IS) are yet to fulfill clinical requirements. This study used non-targeted metabolomics to investigate differential metabolites and metabolic pathways in plasma and brain tissue following IS, with the aim of identifying new potential biomarkers and therapeutic targets. Twelve Tibetan miniature pigs were randomly assigned to a model- or sham-operation group. An electrocoagulation-based anterior temporal approach was employed to occlude the middle cerebral artery, thereby creating a model for IS. Plasma and brain tissue samples were collected 36 h post-surgery and analyzed using liquid chromatography-mass spectrometry. Principal component and partial least squares discriminant analyses were used to screen for differential metabolites and exclude exogenous metabolites at p<0.05. Compounds were classified according to the HMDB (Human Metabolome Database), and subjected to KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway and VIP (variable importance in projection) analyses. Plasma metabolomics revealed that 86 metabolites were upregulated while 149 were downregulated, with (Z)-3-oxo-2-(2-pentenyl)-1-cyclopentylacetic acid, trans-cinnamic acid and cinnamoylglycine determined to be significant metabolites. Fifty-eight differential metabolites were upregulated in brain tissue and 53 were downregulated, with 2,3-dihydroflavon-3-ol, guanidinoacetic acid (GAA), N-acetyl-D-tryptophan, oxidized glutathione, 2-hydroxyquinoline, and N-acetyl-L-aspartate (NAA) identified as significant metabolites. Organic acids and derivatives, lipids and lipid-like molecules, organoheterocyclic compounds, and organic oxygen compounds were found to be common compound categories among the top five types of compound in both plasma and brain tissue. Common metabolic pathways in plasma and brain tissue include amino acid metabolism, digestive system, cancer overview, and lipid metabolism pathways, with the (Z)-3-oxo-2-(2-pentenyl)-1-cyclopentylacetic acid, GAA, oxidized glutathione, and NAA metabolites serving as potential biomarkers. This study provides a theoretical foundation for the early screening and development of clinical treatment strategies for IS.

Thromboxane A₂ (TXA₂), a prothrombotic factor that induces platelet aggregation and thrombosis, acts as a vasoconstrictor by activating TXA₂ receptors (TP receptors). TXA₂ is extremely unstable and metabolizes into three major metabolites: 2,3-dinor thromboxane B₂ (2,3-dinor-TXB₂), 11-dehydro TXB₂(11-dh-TXB₂), and 11-dehydro-2,3-dinor TXB₂(11-dh-2,3-dinor-TXB₂). 8-Iso-prostaglandin F_2α(8-iso-PGF_2α), a prostaglandin-like compound widely considered the best biomarker of oxidative stress, can also activate TP receptors. The accurate quantification of TXA₂ metabolites and 8-iso-PGF_2α is critical in cardiovascular disease (CVD).

In this study, a method based on ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for the simultaneous determination of 2,3-dinor-TXB₂,11-dh-2,3-dinor-TXB₂, 11-dh-TXB₂, and 8-iso-PGF_2α in human urine. Urine samples were collected from healthy volunteers and patients with CT- or MRI-confirmed ischemic stroke occurring less than 48 h earlier, and cryopreserved at -80 ℃ within 1 h after collection. The urine samples were thawed at room temperature and acidified to pH 2.0-4.0 using hydrochloric acid. The supernatant was collected after centrifugation. A total of 1 mL of each urine sample was added with 100 μL of the internal standard working solution and mixed well. The samples were loaded onto a C18 SPE column (50 mg). The SPE cartridges were preconditioned with 500 μL of methanol and then equilibrated with 500 μL of water. After sample loading, the SPE cartridges were washed with 500 μL of water, 500 μL of 5% methanol aqueous solution containing 0.5% (v/v) ammonia, and 500 μL of 5% methanol aqueous solution containing 2% (v/v) formic acid. The cartridges were dried, and the analytes were eluted with 400 μL of methanol. The eluents were dried and subsequently reconstituted with 50 μL of 13% acetonitrile aqueous solution. After filtration through a filter membrane, the samples were analyzed on an ACQUITY UPLC^® BEH phenyl column (50 mm×2.1 mm, 1.7 μm) via gradient elution using 2 mmol/L ammonium acetate aqueous solution containing 0.002% (v/v) ammonia and acetonitrile as the mobile phases. The flow rate was 0.3 mL/min, and the column temperature was 40 ℃. The analytes were determined in negative electrospray ionization and multiple-reaction monitoring modes. The four target compounds showed satisfactory linearity within the relevant ranges, with linear correlation coefficients (R²) greater than 0.99. The limits of detection of the method were 0.02 ng/mL for 2,3-dinor-TXB₂ and 0.01 ng/mL for 11-dh-2,3-dinor-TXB₂, 11-dh-TXB₂, and 8-iso-PGF_2α. The limits of quantification were 0.1 ng/mL for 2,3-dinor-TXB₂ and 0.05 ng/mL for 11-dh-2,3-dinor-TXB₂, 11-dh-TXB₂, and 8-iso-PGF_2α. In actual urine, the recovery rates at the LOQ level were in the range of 91.48%-104.87%. The recovery rates at low, medium, and high levels were in the range of 92.95%-104.90%. The intra- and inter-day precisions were in the range of 2.79%-13.01% and 4.45%-13.67%, respectively. The relative error (RE) between the average peak area of the mixed matrix and the sum of the ratios of the pure solution and urine matrices was within ±20%. The samples were stable at 4 ℃ for 24 h and at -70 ℃ for 10 d. The developed method is the first to realize the simultaneous determination of 2,3-dinor-TXB₂, 11-dh-2,3-dinor-TXB₂, 11-dh-TXB₂, and 8-iso-PGF_2α in urine. The method was used to determine the concentrations of 2,3-dinor-TXB₂, 11-dh-2,3-dinor-TXB₂, 11-dh-TXB₂, and 8-iso-PGF_2α in healthy controls and patients with ischemic stroke, and the results were corrected using creatinine. Binary logistic regression analysis was used to construct the prediction model, and a receiver operating characteristic (ROC) curve was drawn to evaluate the clinical diagnostic ability of the method for the target compounds. TXA₂ was calculated as the sum of its three metabolites. The area under the curve (AUC) of TXA₂ was 0.849, and the method sensitivity and specificity were 69.2% and 92.3%, respectively. The AUC of 8-iso-PGF_2α was 0.775, and the method sensitivity and specificity were 84.6% and 76.9%, respectively. The proposed method has good clinical value and is expected to assist in the early screening and diagnosis of ischemic stroke.

Glufosinate (GLUF) and glyphosate (GLY) are nonselective phosphorus-containing amino acid herbicides that are widely used in agricultural gardens and noncultivated areas. These herbicides give rise to a number of key metabolites, with 3-methyl phosphinicopropionic acid (MPPA), N-acetyl glufosinate (N-acetyl GLUF), aminomethyl phosphonic acid (AMPA), N-acetyl aminomethyl phosphonic acid (N-acetyl AMPA), N-acetyl glyphosate (N-acetyl GLY), N-methyl glyphosate (N-methyl GLY) as the major metabolites obtained from GLUF and GLY. Extensive use of these herbicides may lead to their increased presence in the environment, especially aquatic ecosystems. An increasing number of research studies into the toxicities of GLUF, GLY, and their metabolites have shown that these herbicides are potentially toxic to aquatic biota. GLUF and GLY, as well as their metabolites, are extremely polar and water-soluble, and they lack chromogenic and fluorescent groups; therefore, their concentrations are difficult to determine using conventional methods. Most analytical methods used to date have largely depended on derivatization procedures, leading to overall determination processes that are tedious and time-consuming. Therefore, establishing a quick and sensitive method that does not require derivatives for determining GLUF, GLY, and their metabolites in water environments, including surface water, sediments, and aquatic organisms, is an important endeavor.

In this study, a new approach was developed based on pass-through solid-phase extraction coupled with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) to determine GLUF, GLY, and their metabolites, including MPPA, N-acetyl GLUF, AMPA, N-acetyl AMPA, N-acetyl GLY, and N-methyl GLY, in sediments. Samples were extracted with 4% (v/v) ammonia water and purified using PRiME HLB pass-through solid-phase extraction columns. The extracts were filtered through a polyethersulfone microfiltration membrane and analyzed by UHPLC-MS/MS. Compounds were separated on a Metrosep A Supp 5 column (150 mm×4.0 mm, 5 μm) using gradient elution with water and 200 mmol/L ammonium hydrogen carbonate solution containing 0.05% (v/v) ammonia water as the mobile phases. Analytes were detected using MS/MS with a negative electrospray ionization (ESI^-) source in the multiple reaction monitoring (MRM) mode. A matrix-matched external-standard approach was used for quantitative analysis. GLUF, GLY, and their metabolites were detected within 15 min with good peak shapes and high responses. Calibration curves were linear in the range of 2.0-200 μg/L, with correlation coefficients exceeding 0.995. This method delivered limits of detection (LODs) and limits of quantification (LOQs) of 5 μg/kg and 20 μg/kg, respectively, for GLUF, MPPA, N-acetyl-GLUF, N-acetyl AMPA, N-acetyl GLY, and N-methyl GLY, and 10 μg/kg and 30 μg/kg, for GLY and AMPA, respectively. Average spiked recoveries at three levels (LOQ, 5LOQ, 10LOQ) in sediment with low organic matter content were in the range of 78.5%-107%, and the relative standard deviations (RSDs) were in the range of 1.32%-14.7% (n=6). Average spiked recoveries of 76.4%-113% were determined for three levels (LOQ, 5LOQ, and 10LOQ) in sediments with high organic matter contents, with RSDs of 2.60%-11.2% (n=6). The developed method was used to analyze GLUF, GLY, and their metabolites in ponds, lakes, reservoirs, and river sediments. No target compounds were detected in any sediment sample obtained from a lake, reservoir, or river; however, GLY and AMPA were detected in one pond-sediment sample at levels of 31.7 and 52.3 μg/kg, respectively. The developed approach is simple, fast, and green; moreover, it offers advantages, including high accuracies, high sensitivities, and good reproducibilities. Accordingly, the developed method is suitable for determining GLUF, GLY, and their metabolites in sediments and can provide technical support for studying residue characteristics and environmental behavior in sediments.

To evade legal controls, new psychoactive substances (NPS), which have been designed as substitutes for traditional and synthetic drugs, are gradually dominating the drug market. Synthetic cannabinoids (SCs), which account for the majority of NPS, are rapidly being derivatized; consequently, controlling increasing abuse by merely listing individual compounds is difficult. Therefore, China has included the entire SC category of SCs listed as legal controlled substances since July 1, 2021. However, new SCs obtained through structural modification are still appearing and pose significant analytical challenges for forensic laboratories. Therefore, an efficient, green, and automated detection method is urgently required to provide technical support for the accurate screening actual samples. Meanwhile, the number of indazole-type SCs has increased sharply since 2013, which is ascribable to their stronger psychoactive effects. Indeed, forensic laboratories mainly analyze this key SC subclass. Therefore, in this study, we developed a new method for analyzing 51 indazole-type SCs in human urine and blood, which involves online solid-phase extraction (online SPE) as the preprocessing technology, with analysis performed using liquid chromatography-linear ion trap mass spectrometry. Deproteinization was achieved by adding acetonitrile, with dilution performed using 10 mmol/L ammonium acetate solution (pH 4.8) containing 0.1% formic acid. Samples were then analyzed directly using acetonitrile-10 mmol/L ammonium acetate aqueous solution (containing 0.1% formic acid) as the mobile phase. The mass-to-charge ratios of protonated molecular ions ([M+H]⁺) in the mass spectra acquired in full-scan mode, and the retention times in the chromatograms of the analytes were selected with the aim of monitoring the MS² ions of the various compounds. Characteristic fragment ions of the various SC structures were summarized, with five groups of isomers, each containing ten compounds, successfully distinguished using multistage mass spectrometry and their retention times. Multistage MS was used to qualitatively screen 51 indazole-type SCs, which were then quantitatively analyzed using MS² ion pairs (as quantitative ion pairs). The analytes exhibited limits of detection (LODs) of 0.02-1 ng/mL, with limits of quantification (LOQs) of 0.04-4 and 0.1-4 ng/mL in urine and blood, respectively. Linear fitting (weighting factor 1/x) revealed good linearity for each analyte within its respective linear range, with correlation coefficients (R²) greater than 0.99 in both urine and blood. The validity of the analytical method was tested by determining precision and spiked recovery values (n=6). Recoveries of 83.47%-116.95% were obtained at LOQ levels, with precisions of 2.29%-13.40%. In addition, recoveries of 86.63%-113.38% and precisions of 0.58%-13.79% were obtained at low, medium, and high levels. The method described herein is not only easy to operate but also can be automated. Indeed, high-throughput sample analysis was achieved when sample extraction, enrichment, and analysis were performed in dynamic mode through valve switching. Meanwhile, the method exhibited good sensitivity and is applicable to a wider range of compounds than those previously reported; it also provides a scientific basis and technical support for the rapid screening and quantitative analysis of SCs in actual relevant cases.

High performance liquid chromatography (HPLC) is a key analytical technique that is used in a number of fields. Improving the separation efficiency, stability, and universality of HPLC has been a continuing analytical-chemistry focus. In chromatographic separation, factors such as the composition and ratio of the mobile phase, the type of stationary phase, and the dimensions of the chromatographic column significantly affect the separation efficiency. In addition, the temperatures of the chromatographic column and mobile phase are also important for achieving separation. The column oven is usually used to stably control the column temperature in the HPLC separation system. Indeed, highly accurate temperature control ensures superior separation performance, short analysis times, and repeatability. In this study, we innovatively improved the traditional column oven by combining a variety of temperature-control algorithms to deliver continuous and highly accurate temperature control in the wide 4-90 ℃ range, and by exploring a new chromatographic-method development route. Instead of focusing on the complex hardware system, we optimized the software to achieve highly stable and accurate (±0.1 ℃) temperature control. Temperature-control performance was further improved by optimizing the structure of the thermal insulation and employing reliable and environmentally friendly thermal-insulation materials. Additionally, the thermal conduction of the heat-source device is discussed based on the heat-transfer principle with the aim of improving the performance of the column oven. The improved column oven delivered significantly enhanced chromatographic-separation repeatability and stability thereby reliably guaranteeing the development of highly efficient chromatographic analysis methods.

A comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOF-MS) method was developed to analyze 25 traditional phthalate esters (PAEs) and 19 novel alternatives in indoor dust samples. PAEs are ubiquitous in indoor environments because they are widely used as plasticizers in a variety of consumer products, and potential health concerns have prompted the need for effective monitoring methods. In this study, dust samples were collected from various indoor settings in a university campus, including classrooms, cafeterias, laboratories, and dormitories, and were subsequently ultrasonically extracted with hexane-dichloromethane (1∶1, v/v) solution for 30 min. This method was chosen to maximize PAE recovery while minimizing potential interference from other compounds present in the dust matrix. Compounds were separated on a Rix-5MS column (30 m×0.25 mm×0.25 μm) as the first dimension, with a Rix-17Sil column (1.39 m×0.25 mm×0.25 μm) serving as the second dimension. The following temperature program was used: 60 ℃ for 1 min, then increasing to 220 ℃ at 20 ℃/min, followed by a further increase to 290 ℃ at 5 ℃/min, with the final temperature held for 8 min; this program was optimized to afford maximum target-compound resolution and sensitivity. The developed method rapidly, accurately, and sensitively detected the target PAEs and their alternatives under the optimal conditions, which included a carrier-gas flow rate of 1.4 mL/min, a modulation period of 4 s, and an injection-port temperature of 250 ℃. The 44 target compounds exhibited highly linear calibration curves across a content range of 1-500 μg/g, with all correlation coefficients exceeding 0.99. The limits of detection (LODs) of the method were determined to lie between 0.57 and 13.0 ng/g, which reflects the high sensitivity of the developed approach. At spiked levels of 1, 10, and 50 μg/g, the recoveries of the analyzed compounds varied from 72.8% to 125%, with relative standard deviations ranging from 1.29% to 14.8% (n=3), which indicates that the method is highly precise and reliable. The developed method was used to analyze PAEs and their alternatives in 40 indoor dust samples, which revealed total contents of between 2.07 and 354 μg/g in dust samples. Di-2-ethylhexyl phthalate (DEHP) emerged as the most frequently detected compound, with contents ranging from “not detected” (nd) to 158 μg/g. The novel alternative, bis(2-ethylhexy) terephthalate (DEHTH), was also detected, with levels ranging from nd to 117 μg/g. Notably, significant differences in the compositions and contents of the PAEs and their alternatives were observed across various indoor environments, which suggests that diverse sources and exposure pathways exist for these compounds, highlighting the necessity for ongoing PAE monitoring and risk assessment in various indoor settings. In conclusion, the developed GC×GC-TOF-MS method provides a powerful tool for comprehensively analyzing PAEs and their alternatives in indoor dust; it is well-suited for the routine monitoring of these compounds owing to its simplicity, rapidity, and robustness. These findings provide valuable insight for future research into the sources and health implications of PAEs in indoor environments, and ultimately support risk assessment and regulatory efforts.

Experimental courses in pharmaceutical analysis are an important part of the training process for pharmaceutical talent. These courses focus on applying theoretical knowledge in practice and using large instruments, with the aim of inspiring innovative thinking and cultivating student development. Currently, several issues impede the success of experimental pharmaceutical analysis courses both in China and abroad. In domestic colleges and universities, the content of these courses varies significantly and is relatively unsophisticated. Owing to economic and human resource limitations, students lack training in the operation and use of large analytical instruments. In foreign universities, the range of professional instruments is not comprehensive, experimental class hours are limited, and the availability of large instruments for experimental teaching is insufficient. The School of Pharmaceutical Science and Technology, Faculty of Medicine, Tianjin University, explored the teaching assistant system with group rotation for the delivery of experimental pharmaceutical analysis courses. In combination with the large instrument sharing platform of the school, this approach resulted in a relatively comprehensive teaching model. This model reduced the demand for experimental instruments at a certain time by extending the time axis, thereby relieving the pressure on large instrument allocation. Furthermore, a complete pharmaceutical analysis teaching program was designed according to the curriculum requirements, covering common analytical methods and instruments used in pharmaceutical analysis. With guidance from experimental teaching assistants, students consolidated their theoretical knowledge, mastered key techniques for drug quality control and the drug research process, and laid a foundation for developing new drug analysis methods. Over years of continuous exploration, this model has matured to achieve good teaching outcomes. This work can provide a reference for the development of experimental pharmaceutical analysis courses in domestic universities.