Analyzing cosmetics is particularly important from a safety perspective owing to their widespread use in modern society. A wide range of ingredients and substances are restricted and/or prohibited to ensure that cosmetics are safe， with glucocorticoids among the prohibited substances. Glucocorticoids are important hormones that regulate the body’s stress response； they are also widely used as effective anti-inflammatory and immunosuppressive agents in the clinic. However， long-term topical use can lead to allergic reactions and other human-health effects； consequently， their inclusion in cosmetics formulations is prohibited. Glucocorticoids are often illegally abused in cosmetics with the aim of enhancing their anti-allergic and whitening effects. However， analyzing cosmetics is challenging owing to matrix complexity， structural diversity， and the trace-level （μg/kg） presence of glucocorticoids. Rapid and efficient sample pretreatment techniques and sensitive analytical methods are required to address these challenges， which necessitates separating/analyzing glucocorticoids and optimizing the separation/detection workflow. This review presents research progress into sample-pretreatment and analytical methods used to analyze and detect glucocorticoids in cosmetics during the 2010–2024 period. Sample preparation is a critical step when analyzing cosmetics because complex matrices can seriously interfere with the determination of target analytes； hence some separation or enrichment methods often need to be employed when analyzing glucocorticoids in cosmetics. These methods mainly include field-assisted extraction methods， such as ultrasonic-assisted， vortex-assisted， and electric-field-assisted extraction， phase-partitioning methods， such as liquid-liquid extraction and liquid-liquid microextraction， as well as phase-adsorption methods， such as solid-phase microextraction and solid-phase， dispersive-solid-phase， and magnetic-solid-phase extraction. Cosmetics are divided into three categories according to the matrix： aqueous， emulsion， and cream. Creams and emulsions contain many wax-based and lipid substances that often need to be separated and enriched by methods that involve binding field assistance or phase separation， with solid-phase extraction associated with the most （more than 40%） literature reports. Glucocorticoid dissolution is often accelerated by ultrasonic-assisted or vortex-assisted methods prior to solid-phase extraction or solid-phase microextraction. In addition， methods used to analyze and detect glucocorticoids in cosmetics mainly included liquid-chromatography， chromatography-mass spectrometry， and capillary electrophoresis in the 2010–2024 period， as well as rapid detection methods that are discussed in this review. Statistically， 64% of the reports in this timeframe use chromatography-mass spectrometry methods， with chromatography-related methods accounting for 85% of the methods used to analyze and detect glucocorticoids in cosmetics. Methods for rapidly testing glucocorticoids in cosmetics， including spectroscopy and colorimetry， among others， are also presented in this review owing to the sheer size of the market for beauty products and the high demand for on-site testing. With this background in mind， the separation and analysis of glucocorticoids in cosmetics are anticipated to show developmental trends. Currently， solid-phase extraction and other pretreatment technologies， along with liquid chromatography- and chromatography-mass spectrometry-based detection techniques are the main quality-control avenues for cosmetics. However， on the one hand， glucocorticoid structural diversity and the continuous discovery and use of new glucocorticoids necessitate the development of new analytical methods. In particular， integrating high-resolution mass spectrometry， nuclear magnetic resonance spectroscopy， and big-data-analysis methods when developing efficient qualitative and quantitative analytical methods is significantly important from a practical perspective. On the other hand， the development of rapid， efficient， and universal pretreatment technologies for glucocorticoids is key to effectively separating and analyzing them in cosmetics and is expected to receive increasing levels of attention. Furthermore， rapid analysis， especially analytical techniques suitable for rapid on-site screening， are expected to become focuses for the detection of glucocorticoids in cosmetics in response to the growing regulatory requirements of the cosmetics market. Integrating sample-pretreatment and analytical-detection methods， along with the development of visualized， integrated， and automated rapid-detection technologies， is expected to facilitate rapid on-site sampling and high-throughput cosmetics testing.

The analysis of complex sample matrices， such as environmental samples， food commodities， and biological specimens， requires sophisticated pretreatment methods. These techniques are fundamentally critical for isolating and enriching analytes of interest， thereby substantially enhancing the sensitivity， accuracy， and efficiency of subsequent analytical procedures. The judicious selection of adsorbent materials represents the pivotal element in achieving effective pretreatment. In recent years， ionic liquid-functionalized magnetic Fe₃O₄ nanoparticles （IL-Fe₃O₄ NPs） have garnered significant attention as highly promising materials within this domain. Their potential arises from an exceptional combination of properties： outstanding chemical and colloidal stability， high adsorption capacity， abundant surface active sites， superior solvation capabilities for diverse organic and inorganic compounds， potential for regeneration and reuse， and facile magnetic separation facilitated by an external magnetic field. Ionic liquids （ILs） are characterized by their structurally tailorable nature， excellent ionic conductivity， and potent dissolution capabilities. These intrinsic attributes render ILs highly effective as modifiers for Fe₃O₄ nanoparticles， either applied singularly or in hybrid composites with other functional materials. This surface functionalization fulfills two essential roles： firstly， it effectively mitigates the inherent tendency of nanoparticles towards agglomeration and provides a protective layer against oxidation； secondly， it circumvents well-documented limitations associated with bulk ionic liquids， notably their high viscosity （which impedes diffusion kinetics and mass transfer efficiency） and the practical difficulties often encountered in their separation from liquid phases. Consequently， IL-Fe₃O₄ NPs demonstrate particular utility for the efficient enrichment of trace-level analytes， such as metal ions. The resulting composite material successfully retains the advantageous core properties of the magnetic Fe₃O₄ substrate， specifically its superparamagnetic behavior （enabling rapid and efficient magnetic separation） and inherent biocompatibility. Simultaneously， it incorporates the highly desirable characteristics of ionic liquids， namely their extensive structural design flexibility and ease of chemical functionalization. The adsorption and extraction of analytes by IL-Fe₃O₄ NPs are governed by a complex interplay of multiple intermolecular forces. These encompass π-π stacking interactions， electrostatic attractions， hydrogen bonding， hydrophobic effects， and potentially coordinative interactions. This multifaceted binding capability underpins the material’s demonstrated high adsorption efficiency and selectivity towards various analytes. Currently， IL-Fe₃O₄ NPs are extensively employed across a broad range of modern sample pretreatment techniques. Principal methodologies include magnetic solid-phase extraction （MSPE）， in-tube solid-phase microextraction （IT-SPME）， and pipette-tip solid-phase extraction （PT-SPE）. Furthermore， these functionalized nanoparticles exhibit excellent compatibility for integration—both in online and offline configurations—with established analytical detection platforms. This includes coupling with chromatographic techniques such as high performance liquid chromatography （HPLC） and gas chromatography （GC）， as well as spectroscopic methods including atomic absorption spectroscopy （AAS） and inductively coupled plasma mass spectrometry （ICP-MS）. The seamless coupling of IL-Fe₃O₄ NPs-based extraction with these detection systems significantly augments overall method sensitivity and analytical accuracy. As a result， these materials show considerable promise for impactful applications in critical areas such as food safety assurance， environmental contaminant monitoring， and biomedical analysis. This article systematically summarizes the synthesis methods， classifications， main extraction modes， online or offline detection techniques， and applications in sample pretreatment of IL-Fe₃O₄ NPs， while also providing an outlook on potential future exploration directions for this class of materials.

Porous organic cages （POCs） are a new class of porous materials formed by the assembly of discrete three-dimensional cage-like molecules through intermolecular forces. They possess good solubility and well-defined intrinsic molecular cavities， making them an extremely attractive medium for chromatographic separation. In this study， a chiral porous organic cage （CC3-R， C₇₂H₈₄N₁₂） was synthesized using 1，3，5-triformylbenzene and （1R，2R）-diaminocyclohexane as raw materials， and it was then reduced by NaBH₄ to obtain RCC3-R （C₇₂H₁₀₈N₁₂）. After post-modification of RCC3-R with 5-bromo-1-pentene to introduce carbon-carbon double-bond functionalized linker arms， it was successfully bonded to the surface of thiolated silica via thiol-ene click reaction to prepare a chiral stationary phase （CSP） for high performance liquid chromatography （HPLC）. The successful synthesis of CC3-R， RCC3-R and CSP was confirmed by various characterization methods such as nuclear magnetic resonance （NMR）， Fourier-transform infrared spectroscopy （FT-IR）， high resolution mass spectrometry （HRMS）， thermogravimetric analysis （TGA）， and elemental analysis （EA）. The enantioseparation performance of the CSP was evaluated by separating various types of racemic compounds， including alcohols， esters， ketones， aldehydes， amines， and organic acids in both normal-phase （NP） and reversed-phase （RP） elution modes. The results demonstrate that the CSP achieved enantioseparation of 18 and 16 racemates in NP and RP modes， respectively. Among them， 12 racemates achieved baseline separation in NP elution mode， while 7 racemates achieved baseline separation in RP elution mode. Moreover， the CSP-packed column exhibited good complementarity in chiral separation with two widely used commercial columns， Chiralcel OD-H and Chiralpak AD-H， enabling the separation of some racemic compounds that cannot be separated on these two commercial columns. In NP elution mode， 7 of the 18 tested racemates could not be enantioseparated on Chiralpak AD-H column， and 4 of the 18 tested racemates could not be enantioseparated on Chiralcel OD-H column. In RP elution mode， 8 of the 16 tested racemates could not be enantioseparated on Chiralpak AD-H column， and 5 of the 16 tested racemates could not be enantioseparated on Chiralcel OD-H column. The effects of column temperature and injection mass on chiral separation performance of the RCC3-R column were investigated. In addition， the RCC3-R column exhibited excellent repeatability and stability. After hundreds of injections， no significant changes were observed in the retention times and resolution values of the analytes compared to the initial use of the column， with relative standard deviations （RSDs， n=5） of less than 0.50% and 1.30%， respectively. Furthermore， the RSDs （n=3） of retention times and resolution values of the racemates separated on RCC3-R columns prepared in different batches were less than 1.89% and 4.10%， respectively. This study demonstrates that the chiral POC RCC3-R is a potentially valuable chiral separation material for HPLC. It also holds significant importance for the research on novel CSPs for HPLC based on chiral POCs.

Goji berries and mulberries are susceptible to pest and pathogen invasion due to their high sugar content and the impact of growth environment. Their quality and safety are primarily influenced by pesticide residues and mycotoxins. This study has developed a simple， high-throughput， and sensitive analytical method for the simultaneous determination of 172 pesticides and 11 mycotoxins in the medicinal and edible substances of goji berries and mulberries using an improved QuEChERS method coupled with liquid chromatography-quadrupole-time of flight mass spectrometry （LC-Q-TOF/MS）. The sample was hydrated with 7 mL of purified water， and 10 mL of 5% formic acid in acetonitrile was added as the extraction solvent， along with 4 g of anhydrous MgSO₄ and 1 g of NaCl as extraction salts. The extract was purified using 400 mg of anhydrous MgSO₄， 150 mg of primary secondary amine （PSA）， 100 mg of octadecylsilane （C₁₈）， and 5 mg of multi walled carbon nanotubes （MWCNTs）. The supernatant was dried under nitrogen， and the residue was reconstituted in 1.0 mL of a methanol-water solution （3∶2， volume ratio）， homogenized by ultrasonication， and filtered through a 0.22 μm membrane prior to analysis. Separation was performed on a ZORBAX SB-C₁₈ column （100 mm×2.1 mm， 3.5 μm） using a mobile phase consisting of 0.1% formic acid in aqueous solution （containing 5 mmol/L ammonium acetate） and 0.1% formic acid in methanol. Detection was carried out using electrospray ionization in positive mode with full ion MS/MS （All Ions MS/MS） scanning. Quantitation was achieved using a matrix-matched external calibration method. The results showed that this method can effectively reduce matrix effects， and 183 compounds exhibited good linearity within their respective ranges， with linear correlation coefficients （R²） greater than 0.995. The screening detection limits （SDLs） and limits of quantification （LOQs） for 172 pesticides in goji berries ranged from 1 to 50 μg/kg and 5 to 50 μg/kg， respectively. For mulberries， the SDLs and LOQs ranged from 1 to 20 μg/kg and 5 to 20 μg/kg， respectively. Additionally， the SDLs for 11 mycotoxins in goji berries were between 1 and 20 μg/kg， with corresponding LOQs of 5 to 50 μg/kg. In mulberries， the SDLs ranged from 1 to 10 μg/kg， while the LOQs were between 5 and 20 μg/kg. Overall， the LOQs of 183 compounds in mulberries were less than 20 μg/kg， and the proportions of pesticides and mycotoxins with LOQs less than 20 μg/kg in goji berries were 98.3% and 81.8%， respectively. At the spiked levels of 1， 2， and 10 times LOQs， the recoveries of 183 compounds ranged from 70.0% to 118.5%， 70.6% to 118.8%， and 71.2% to 119.0%， respectively， with relative standard deviations （RSDs） all less than 20.0%. The intra-day precision and inter-day precision of goji berries were 0.7%-9.8% and 1.0%-17.3%， respectively， whereas for mulberries were 0.8%-9.9% and 1.5%-16.0%， respectively. This method was applied to detect pesticides and mycotoxins in 15 batches of goji berries and 10 batches of mulberries， and a total of 16 compounds （including 13 pesticides and 3 mycotoxins） were detected with contents ranging from 5.61 to 622.47 μg/kg. Both detection rate and average content of pesticides and mycotoxins in goji berries were higher than those in mulberries. In addition， a preliminary risk assessment was conducted on the neonicotinoid pesticides with high detection rates （acetamiprid and imidacloprid）. The results showed that the chronic dietary intake risk values （%ADI） of acetamiprid and imidacloprid in goji berries were 0.04% and 0.02%， respectively. Both values are below 100% of the ADI in goji berries and are within acceptable limits. To ensure the safety and quality of goji berry and mulberry products， it is necessary to enhance the management and storage condition control of pesticides and mycotoxins. The results indicated that this method is simple to operate， highly sensitive， and suitable for high-throughput qualitative screening and accurate quantification of multiple pesticide residues and mycotoxins in both goji berries and mulberries. This method can provide reference for high-throughput screening of pesticide residues and mycotoxins in other berry medicinal and edible substances. Furthermore， it can indirectly promote industrial upgrading， facilitate the internationalization of medicinal and edible substances， and achieve a win-win situation regarding health value and economic benefits through technological innovation and the enhancement of standards.

Pyrrolizidine alkaloids （PAs） are natural toxins widely distributed in plants， which naturally occur in about 3% of the world’s flowering plants. To date， more than 660 PAs and their nitrogen oxides have been identified in over 6 000 plants. Some PAs are hepatotoxic， genotoxic and tumorigenic， posing significant health risks to humans. These alkaloids are commonly detected as contaminants in various food products， including tea， grains， milk， honey， as well as plant-derived pharmaceuticals and dietary supplements. Currently， most studies on the quantitative methods for PAs focus on a limited number of PAs and employ an additive quantification strategy， largely due to the challenges associated with chromatographic separation of isomers. These approaches limit the ability to assess exposure and health risk accurately. Herein， a method was established to quantify 35 PAs individually in dried tea samples using ultra-high performance liquid chromatography-triple quadrupole mass spectrometry （UHPLC-MS/MS）. The 35 target compounds were divided into two groups. The first group included 30 PAs， while the second group consisted of 5 PAs. These compounds were separated on Waters Acquity BEH C18 （150 mm×2.1 mm， 1.7 μm） and Thermo Acclaim^TM C30 （150 mm×2.1 mm， 3.0 μm） chromatographic columns， respectively. Mobile phases were H₂O containning 5 mmol/L ammonium formate and 0.13% formic acid （pH=3） and methanol-acetonitrile （4∶6， volume raio） containing 0.1% formic acid. The 33 target compounds were separated and 2 isomers co-eluted. Under positive-ion electrospray ionization （ESI） and multiple reaction monitoring （MRM） mode， target compounds were quantified using the external standard method with the matrix-matched standard curve. The results demonstrated that all target compounds showed good linearity （r²>0.99） in their respective mass concentration ranges. The limits of detection （LODs） and quantification （LOQs） of the method were in the range of 0.2-8.0 µg/kg and 0.5-25.0 µg/kg， respectively. The average recoveries of more than 89% compounds were in the range of 70%-130% at spiked levels of 1， 2， and 5 fold-LOQs and the relative standard deviations （RSDs） were less than 20% （RSDs of lasiocarpine and echimidine were less than 30%）. Moreover， the quantitative method of the 35 PAs was applied to 21 dark tea and 30 black tea samples from Yunnan and Fujian Province， where PAs were detected in 4 dark samples with total contents ranging from 5.07 to 15.48 µg/kg and were not detected in black tea samples. The detection rate of PAs in dark tea samples was higher than that of black tea samples. That might be because most dark tea was processed from fresh leaves picked by machines， and this attribution could be associated with the mixing of weeds containing PAs during tea harvesting. And the detected concentrations of all samples were lower than the maximum levels of tea in European Union regulations， indicating that the tea samples involved in this research are basically safe. In brief， the quantitative method of the 35 PAs facilitates the analysis of the occurrence， composition and potential risks in tea samples.

Tetracyclines （TCs） are broad-spectrum antibiotics that are classified as natural or semi-synthetic. Natural TCs include chlortetracycline， tetracycline， and oxytetracycline， while semi-synthetic ones include doxycycline， minocycline， methacycline， and demeclocycline， among others. While TCs are widely used in the livestock， poultry， and aquaculture industries， their indiscriminate use detrimentally affects ecosystems， and residual TCs in animals can adversely affect human health. In this study， we developed an ultra-performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS） method for determining TCs， including minocycline， 4-epioxytetracycline， 4-epitetracycline， oxytetracycline， tetracycline， demeclocycline， 4-epichlortetracycline， chlortetracycline， methacycline， and doxycycline. The developed protocol was used to establish a method for qualitatively and quantitatively analyzing TCs in animal muscle tissue （pork， chicken， and fish meat）. To this end， we systematically optimized the mass spectrometry （MS） parameters， solid-phase extraction （SPE） cartridge， and extraction conditions of the method. Animal muscle-tissue samples were homogenized and extracted with 10 mL of 80% acetonitrile aqueous solution containing 0.2% formic acid. How the acetonitrile/formic acid ratio affects the TC-extraction efficiency was investigated using one-way analysis. The supernatant was purified using an Oasis PRiME HLB solid-phase-extraction cartridge， evaporated under flowing nitrogen， and redissolved. Two different C₁₈ UPLC columns were systematically evaluated， and the optimal UPLC conditions were established for the TCs. The Eclipse Plus C₁₈ column （100 mm×2.1 mm， 3.5 μm） was used for separation. The effects of mobile phases A （0.1% formic acid aqueous solution， 5 mmol/L ammonium acetate aqueous solution， and 5 mmol/L ammonium formate aqueous solution） and B （methanol or acetonitrile） on the separation and response values of the TCs were investigated. Optimal response values and peak shapes were obtained using 0.1% formic acid aqueous solution as mobile phase A and 0.1% formic acid acetonitrile solution as mobile phase B， at a flow rate of 0.2 mL/min and a sample injection volume of 5 μL. Gradient elution was performed as follows： 0–2.0 min， 5%B； 2.0–3.5 min， 5%B-15%B； 3.5–7.0 min， 15%B-20%B； 7.0–9.0 min， 20%B-65%B； 9.0–9.1 min， 65%B-90%B； 9.1–10.0 min， 90%B； 10.0–10.1 min， 90%B-5%B； 10.1–12 min， 5%B. The effect of the glass sample bottle on adsorption was also investigated. Both positive- and negative-ion modes were explored in the UPLC-MS/MS experiment to fully scan the parent ions. Positive mode was selected for electrospray ionization （ESI）. Two product ions that exhibit strong signals and minimal interference were selected for quantitative and qualitative ion analyses， with quantification performed using the external standard method. Tandem mass spectrometry （MS/MS） was performed in positive electrospray ionization （ESI⁺） and multiple reaction monitoring （MRM） modes. The following MS/MS parameters were used： capillary voltage， 0.5 kV； cone voltage （CV）， 30 V； ion-source temperature， 150 ℃； desolvation temperature， 300 ℃； desolvation gas flow， 800 L/h. Other instrument settings， such as the collision energy （CE） and collision gas flow， were also optimized. The TCs exhibited good linearities within the 1–500 ng/mL mass-concentration range， with all correlation coefficients （r²） above 0.994， and limits of detection and quantification （LODs and LOQs） of 0.10–0.15 and 0.20–0.50 μg/kg， respectively. The target analytes exhibited average recoveries of between 62.6% and 119.0% at three levels （1.0， 5.0， and 10.0 μg/kg）， with relative standard deviations （RSDs， n=7） ranging from 2.0% to 9.8%. The developed method was used to determine TCs in 60 animal muscle-tissue samples acquired from a fresh-food supermarket. Tetracycline was detected at a rate of 10% in 20 pork samples， while doxycycline was detected at a rate of 15% in 20 chicken samples， and oxytetracycline was detected at a rate of 5% in 20 fish-meat samples. Minocycline， 4-epioxytetracycline， 4-epitetracycline， tetracycline， demeclocycline， 4-epichlortetracycline， chlortetracycline， and methacycline were not detected. The developed method is simple to operate， highly sensitive， and can be used to precisely and accurately determine TCs. Accordingly， it is suitable for determining the abovementioned ten tetracycline antibiotics in animal muscle tissue.

As chemical agents that selectively inhibit weed growth， herbicides play a crucial role in enhancing crop yields. With increasing weed resistance， the environmental residue problems caused by excessive application have become increasingly prominent. Studies indicate that only 20%–30% of field-applied herbicides are effectively utilized， with the remainder entering environmental media such as the atmosphere， soil， sediment， and surface water through runoff and leaching. Recent frequent occurrences of vegetable phytotoxicity incidents in Shanghai have been traced to potential associations with herbicide residues in surface water， further highlighting the urgent need to establish multi-residue analytical methods for environmental media. An analytical method was established based on ultra-high performance liquid chromatography-tandem mass spectrometry （UHPLC-MS/MS） for determining 26 herbicide residues in soil， sediment， and surface water. Instrumental detection parameters were optimized， including electrospray ionization mode， mobile phase， and chromatographic column. The mobile phase consisted of 0.1% formic acid aqueous solution （A） and acetonitrile （B） with the following gradient elution program： 0–0.5 min， 2%B； 0.5–1 min， 2%B–50%B； 1–4 min， 50%B–65%B； 4–6 min， 65%B–75%B； 6–8 min，75%B–85%B； 8–10 min， 85%B–95% B； 10–11 min， 95%B. Soil and sediment samples were extracted via acetonitrile oscillation followed by salting-out and purified using the QuEChERS method. Surface water samples were directly analyzed after acetonitrile extraction without purification. Different amounts of purification agents were investigated during sample pretreatment. Calibration curves were established by plotting the relationship between analyte concentration and measured peak area using pure solvent and matrix-matched standards. All 26 herbicides showed good linearity in the range of 0.1–50 μg/L with correlation coefficients exceeding 0.999 0. Matrix effects ranged from -35.2% to 14.6% across different matrices. Limits of quantification （LOQs） were 0.5 μg/kg for soil and sediment， 0.1 μg/L for water samples. The herbicides were spiked into soil and sediment at spiked levels of 0.5， 1， and 10 μg/kg， and into surface water at 0.1， 1， and 10 μg/L， respectively. The average recoveries for the 26 herbicides in soil， sediment， and surface water were in the ranges of 73%–108%， 73%–102%， and 74%–110%， respectively. The RSDs for the 26 herbicides were in the ranges of 4.5%–16.2%， 3.8%–19.7%， and 4.0%–15.0%， respectively. The developed method was applied to analyze the contamination status of the 26 herbicides in environmental samples collected from six vegetable cultivation zones in Shanghai. Results revealed distinct pollution patterns： In soil matrices， prometryn （PMT）， metolachlor （MTA）， and sulfometuron-methyl （SMTM） showed higher detection rates of 52.9%， 52.9%， and 29.4%， respectively， with content ranges of 0.8–490.4 μg/kg， 0.5–219.8 μg/kg， and 1.0–562.6 μg/kg. Sediment samples exhibited an 83.3% detection rate for PMT （1.5–6.7 μg/kg）. In surface water， SMTM， PMT， and simetryne （STN） were detected with maximum contents of 12， 2.5 and 1.1 μg/L， respectively， indicating differential migration behaviors across environmental compartments. The proposed method is simple， rapid， accurate， stable， and highly practical. It can be used to detect the 26 herbicide residues in soil， sediment， and surface water and provides a reference for monitoring the residual pollution and environmental behavior of herbicides.

Electronic cigarette refers to electronic delivery systems designed to generate aerosols for human inhalation. In recent years， the global electronic cigarette market has experienced rapid expansion， drawing widespread international attention to its potential health impacts. To protect consumer health， China’s mandatory National Standard for electronic cigarettes issued in 2022 explicitly prohibits the addition of additives and stimulants associated with energy and vitality in electronic cigarette oil. However， to attract consumers， many illicit manufacturers illegally incorporate various stimulating substances into e-liquids. While detection methods have been reported for some illegal additives such as industrial cannabinoids and sweeteners in electronic cigarette oil， there is no fast and reliable detection method for the determination of caffeine and taurine in electronic cigarette oil available to this day. In order to ensure human health， a method was developed for the simultaneous determination of caffeine and taurine in electronic cigarette oil using high performance liquid chromatography-tandem mass spectrometry （HPLC-MS/MS） with a mixed-functional column. Sample preparation involved a simple dilution and filtration step， which was optimized prior to analysis. The analytes were separated on a FMD Comixsil ACRP column （100 mm×2.1 mm， 3.0 μm）. The column temperature was maintained at 30 ℃. The mobile phase consisted of acetonitrile and a 0.1% formic acid solution containing 10 mmol/L ammonium formate with gradient elution. The flow rate was 0.2 mL/min and the injection volume was 1μL. Mass spectrometric detection was carried out using electrospray ionization in positive mode （ESI⁺） with multiple reaction monitoring （MRM）. Under the optimized conditions， both caffeine and taurine were well retained on the chromatographic column， exhibiting excellent， tailing-free peak shapes. The method demonstrated that the limits of detection of caffeine and taurine were 0.100 and 1.00 mg/kg， and the limits of quantification were 0.250 and 2.50 mg/kg， respectively. The linear correlation coefficient （r） was ≥0.997. The average recovery of each component was 88.2%-99.0%， with relative standard deviation （RSD， n=6） between 2.2% and 6.6%. These results indicate that the method is simple， rapid and accurate. It has been successfully applied to the detection of caffeine and taurine in real electronic cigarette oil samples.

Gel nail polish has surged in global popularity， becoming a dominant force in the cosmetics market due to its compelling advantages. This rapid market expansion， however， is shadowed by significant and growing safety concerns related to the essential chemical agents enabling its functionality—photoinitiators （PIs）. Classified as a Category 1B CMR substance （carcinogenic， mutagenic， or toxic to reproduction） based on robust evidence of reproductive toxicity， 2，4，6-trimethylbenzoyl diphenyl phosphine oxide （TPO） has been comprehensively banned within the European Union （EU） under Regulation （EC） No 1223/2009， effective from September 1， 2025. Compounding this challenge was the conspicuous absence of validated analytical methods. Specifically， standardized， reliable， and accessible techniques for quantifying the complex spectrum of PIs in modern gel nail polish formulations were critically lacking. This included established PIs such as the now-banned TPO and its potential substitutes， all of which were embedded within the challenging， heterogeneous matrix of these formulations. This methodological gap severely hindered effective quality control during manufacturing， robust post-market surveillance by regulators， accurate consumer exposure assessment， and the essential safety evaluation of emerging replacement PIs. Consequently， there was an immediate and pressing need to develop dedicated analytical capabilities capable of monitoring both prohibited high-risk PIs and their prospective successors within this specific product category. To address the critical absence of standardized analytical methods for PIs in cosmetics， this study developed and validated a robust high performance liquid chromatography with diode array detection （HPLC-DAD） protocol. The protocol enables the simultaneous quantification of five strategically selected PIs in gel nail polish formulations. These PIs include TPO， its structural analogues ethyl （2，4，6-trimethylbenzoyl） phenylphosphinate （TPO-L）， ［bis（4-methylphenyl） phosphinyl］ （2，4，6-trimethylphenyl） methanone （TMO）， and ［phenyl（2，4，6-trimethylbenzoyl） phosphoryl］ （2，4，6-trimethylphenyl） methanone （PB-TMBPO）， as well as the α-hydroxy ketone 1-hydroxycyclohexyl phenyl ketone （HCHPK）. This target panel encompasses both the currently dominant PIs and prime TPO replacement candidates. The optimized sample preparation involved efficient extraction of target analytes from the complex gel nail polish matrix using acetonitrile under ultrasonication， eliminating the need for derivatization. Chromatographic separation was achieved on a Kromasil 100-5-C18 column （150 mm×4.6 mm， 5 μm） maintained at 30 ℃. A binary mobile phase gradient （water/acetonitrile） was delivered at 1.0 mL/min， with an injection volume of 5 μL. Selective detection leveraged dual wavelengths： 243 nm optimized for HCHPK and 375 nm for the four acylphosphine oxides. Quantitation employed external calibration curves. Method validation demonstrated exceptional performance： All five PIs exhibited baseline separation from matrix interferences. Linear calibration curves spanned 2–600 mg/L with outstanding correlation coefficients （r≥0.999 9 for each analyte）. Method sensitivity was confirmed with limits of detection （LODs） ranging from 3.6 to 45 μg/g and limits of quantitation （LOQs） from 15 to 141 μg/g. Accuracy， assessed through spiked recovery experiments at low， medium， and high concentration levels， yielded excellent results （91.6%–100.4%）. Precision， expressed as relative standard deviation （RSD， n=6）， was consistently high （0.3%–4.3%）， affirming method robustness and reliability for routine analysis. Application of the validated method to 30 commercially available gel nail polish samples revealed pervasive PI presence. Total PI content ranged from 2.95% to 9.66% （mass fraction）. Each batch contained 1 to 3 distinct PIs. None of these PIs were listed on the product labels. Critically， TPO， which has been banned in Europe， was present in 90% of the analyzed products at significant concentrations （1.42%–6.43%， mass fraction）. HCHPK was detected in 76.7% of the samples， with levels ranging from 0.83% to 4.84% （mass fraction）. TPO-L was present in 10% of the samples （6.73%–7.17%， mass fraction）， while TMO was detected at 0.25% （mass fraction） in a single sample. These findings indicate the prevalent use of prohibited substances like TPO and other PIs in the current gel nail polish market. Enhanced regulation， substitution efforts， and further safety assessments are urgently required. This study delivers a simple， specific， rapid， and economically viable HPLC-DAD method specifically tailored for the challenging gel nail polish matrix. It effectively addresses the analytical gap for monitoring key PIs， particularly during the critical transition period following the EU TPO ban. The methodology provides robust technical support for quality control laboratories （both industrial and regulatory）， facilitates compliance verification with evolving safety regulations， enables accurate risk assessment of consumer exposure， and empowers the development of safer gel nail polish formulations through reliable PI quantification. The alarming market data generated underscores the immediate necessity for regulatory action and industry innovation toward eliminating high-risk PIs like TPO.

Vitamins K₁ and K₂ are both essential fat-soluble vitamins for the human body. K₁ was once used in cosmetics for its efficacy in improving dark circles by promoting periorbital circulation. However， due to its potential to cause severe allergic reactions， it is now banned in cosmetics in China and the European Union. K₂， particularly the MK-7 form， has a similar structure to K₁ but features a different side chain. It has gained attention for its skin benefits， including soothing， antioxidant， and anti-aging properties. Although there are no reports of its use in cosmetics in China yet， it has been registered three times as a new cosmetic ingredient， indicating significant market potential. Most existing methods for detecting vitamins K₁ and K₂ focus on pharmaceuticals and dietary supplements， with few studies addressing their analysis in cosmetics， especially vitamin K₂. Given the structural similarity between the two compounds， a reliable method for their simultaneous determination in cosmetic products is needed. However， cosmetic matrices are complex and often interfere with analysis. Conventional sample preparation techniques， such as liquid-liquid extraction and solid-phase extraction， are time-consuming and labor-intensive. The QuEChERS method offers a faster， simpler， and more cost-effective alternative. In this study， we selected six common types of cosmetics—water-based liquids， emulsions， creams， gels， powders， and oils， to develop and validate a simultaneous quantification method for vitamins K₁ and K₂. A QuEChERS-based sample preparation method coupled with high performance liquid chromatography （HPLC） was developed for the simultaneous quantification of vitamins K₁ and K₂ in cosmetics. To enhance specificity and confirmation capability， a complementary method using high performance liquid chromatography-tandem mass spectrometry （HPLC-MS/MS） was also established. Samples were first pre-dispersed with saturated sodium chloride solution， extracted by n-hexane under ultrasonication， and purified using QuEChERS pretreatment technique （containing 150 mg MgSO₄， 50 mg PSA， and 25 mg C₁₈）. For HPLC analysis， separation was performed on a CAPCELL PAK C₁₈ AQ column （250 mm×4.6 mm， 5 µm） using methanol-isopropanol （80∶20， volume ratito） as the mobile phase， with detection at 270 nm. For HPLC-MS/MS confirmation， an ACQUITY UPLC BEH C₁₈ column （50 mm×2.1 mm， 1.7 µm） was employed， with methanol containing 0.05% （volume fraction） formic acid and 5 mmol/L ammonium formate as the mobile phase. Electrospray ionization in positive mode （ESI⁺） and multiple reaction monitoring （MRM） were used for detection. Both HPLC and HPLC-MS/MS methods demonstrated excellent performance for the determination of vitamins K₁ and K₂. In the HPLC method， both analytes showed good linearity over the range of 0.1–50 μg/mL （r>0.999）， with limits of detection （LOD） and quantification （LOQ） of 0.3 μg/g and 1.0 μg/g， respectively. The spiked recoveries ranged from 93.2%-104.5% with RSDs below 5%. For the HPLC-MS/MS method， linearity was observed in the range of 0.005–0.5 μg/mL （r>0.999）， with LOD and LOQ values of 0.02 μg/g and 0.05 μg/g， respectively. Recoveries in this case fell within 89.4%–108.2%， accompanied by RSDs of less than 10%. The method was successfully applied to analyze 30 cosmetic samples spanning six different matrix types. Neither vitamin K₁ nor K₂ was detected in any sample. The proposed methodology is rapid， simple， sensitive， and accurate， making it suitable for routine determination of vitamins K₁ and K₂ in diverse cosmetic products. It offers reliable technical support for quality control and regulatory compliance and demonstrates the utility of QuEChERS sample preparation for the analysis of other cosmetic ingredients.

Ethylene oxide （EO） and acetaldehyde are key components of volatile organic compounds （VOCs） emissions in the petrochemical industry. The ozone formation potential of acetaldehyde is several orders of magnitude higher than that of EO. Therefore， accurately identifying and measuring these compounds is essential for developing effective ozone control strategies. However， separating EO from acetaldehyde presents a considerable analytical challenge due to their isomeric nature and comparable volatilities. In this study， a novel analytical method based on thermal desorption-gas chromatography-mass spectrometry （TD-GC-MS） technology was developed to simultaneously collect， separate， and quantify EO and acetaldehyde. Optimization was performed on the GC column temperature program， thermal desorption temperature， and thermal desorption flow rate to achieve effective separation. Compounds were separated on a TG-624 SiIMS GC column （60 m×0.25 mm×1.4 μm） with a carrier gas flow rate of 1.2 mL/min. To separate EO from acetaldehyde， the GC column temperature was specifically optimized to enhance their differences in desorption rates from the stationary phase. The temperature was initially held at 30 ℃ for 3 min， then ramped at 5 ℃/min to 120 ℃， held for 3 min. Both full scan and selected ion monitoring modes were employed for target detection. During thermal desorption， the thermal desorption temperature was set at 180 ℃， the cold trap temperature was set at -30 ℃ for capturing desorbed targets， and the secondary desorption flow rate was set at 16 mL/min with the corresponding split ratio of 12.3. The method’s performance was evaluated under optimized experimental conditions. Within the range from 1 to 10 ng/tube， the method showed strong linearity with correlation coefficients above 0.99 for EO and acetaldehyde. Method detection limits were determined to be 0.16 ng/tube for EO and 0.21 ng/tube for acetaldehyde. Thermal desorption efficiencies for both targets exceeded 95% with samples spiked at 2 and 10 ng/tube. Recovery efficiencies spiked at 2， 5 and 10 ng/tube ranged from 80.3% to 106.8%， with relative standard deviations ranging from 4.5% to 9.2%. This method was applied to VOCs samples collected from aftertreatment exhaust streams of two petrochemical units， where different concentrations of EO and acetaldehyde were detected. This study thus established a reliable method for the simultaneous collection， identification and quantification of EO and acetaldehyde in petrochemical emission matrices. Furthermore， this method can also be used for monitoring these compounds in diverse emission sources and ambient air， thereby providing essential data to support the management and control of reactive VOCs.