Journal of Chromatography A最新文献

Organic nitrogen species such as alkyl amines (AAs) and free amino acids (FAAs) are increasingly recognized as important contributors to urban aerosol chemistry and potential health risks, yet their concentrations, sources, and seasonal behaviors remain poorly understood. In this study, we developed a rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous determination of 17 AAs and 25 FAAs in PM_2.5, employing simplified pretreatment and isotope-labeled internal standards. Application to PM_2.5 samples collected in Seoul during winter and spring revealed pronounced seasonal contrasts: AAs were elevated in winter and strongly associated with secondary inorganic species and combustion-related pollutants, while FAAs were more abundant in spring, reflecting enhanced biological activity. Correlation analysis with co-pollutants and meteorological parameters highlighted distinct seasonal emission processes and atmospheric transformations. These findings demonstrate the diverse sources and behaviors of nitrogen-containing organics in urban PM_2.5 and underline their implications not only for nitrogen cycling but also for particulate toxicity, air quality management.

The research direction of high-performance liquid chromatography (HPLC) has always focused on the efficient synthesis and precise regulation of stationary phases. Therefore, the creation of chromatographic stationary phases with multiple interactions (hydrophobic, hydrophilic, and ion-exchange interactions), is seen as a critical step in achieving multi-mode chromatographic separation. In this study, an ionic liquid hydrogel was modified onto the surface of bare silica to synthesize a novel stationary phase (Sil@V₁NV₂). When compared to a hydrophilic interactions-dominated hydrogel, the experimental results revealed that the ionic liquid hydrogel not only amplified the hydrophobic interactions but also introduced ion-exchange interactions. This endowed Sil@V₁NV₂ with the capability to separate analytes in multi-mode, including hydrophilic chromatography (HILIC), hydrophobic chromatography (RPLC), and ion-exchange chromatography (IEC). It was noteworthy that the retention factor (k) for both benzoic acid and 4-hydroxybenzoic acid didn't adhere to the Van't Hoff equation. Extensive research has revealed that Sil@V₁NV₂ exhibited temperature-responsive characteristics at elevated temperatures due to the contraction of alkyl chains. This not only provided a reference for further research on ionic liquid hydrogel but also significantly broadened the application range of chromatographic separation in multi-mode.

Phenolic endocrine disrupting compounds (EDCs) contamination poses a serious public health and environmental threat, therefore develop sensitive and selective detection method for phenolic EDCs is highly desirable. A porous organic polymer (DT-POP3) was synthesized by azo coupling of 2,4,6-tris(o-hydroxyaryl)-1,3,5-triazines and 4,4''-diamino-p-terphenyl. DT-POP3 exhibited high adsorption capacity and fast adsorption kinetics for phenolic EDCs through the hydrogen bond force and π-π stacking interaction. With DT-POP3 as solid-phase extraction adsorbent, a LC-MS method was established to detect phenolic EDCs in fish. The method exhibited wide linear range (4.00-1000 ng·g^-1), low detection limit (S/N = 3) (1.20-6.50 ng·g^-1), high spiked recoveries (82.9-118.8%) and low relative standard deviation (1.8-9.6%). The contribution of this study is not merely the proposal of a viable adsorption/detection method for trace phenolic EDCs, but also concurrently establishes a novel paradigm for the development of functional materials aimed at removing organic pollutants.

To address the tedious preparation steps of existing thiol-functionalized chromatographic stationary phases and the scarcity of research on thiol-hybridized core-shell materials, this paper proposes a "one-pot" synthetic route for thiol-hybridized core-shell silica microspheres (SiO₂@SiO₂-thiol). The results demonstrated that the "one-pot" method could efficiently prepare SiO₂@SiO₂-thiol with excellent monodispersity, uniform thiol-hybridized shell layers and tunable pore structures. Subsequently, two types of stationary phases were constructed by utilizing a dual-pathway modification strategy, with these hybrid microspheres as the matrix. The separation performance and mechanism of these stationary phases for both achiral and chiral compounds (such as amino acid racemates) were systematically investigated. The stationary phase modified with hydrophobic 1-tetradecene (C14-thiol-UV) exhibited excellent separation performance, achieving a column efficiency of 55,180 plates m⁻¹ when using butylbenzene as a probe. Furthermore, the combination of C14-thiol-UV column with liquid chromatography-mass spectrometry (LC-MS) enabled effective analysis of perfluorinated compounds (PFASs), further verifying the applicability and practicality of the constructed stationary phase in the separation of complex samples. Meanwhile, compared with two kinds of chiral stationary phases (CSP) in our previous work, the as-prepared thiol‑t‑BuCQN column modified with tert‑butylcarbamoylquinine (t-BuCQN) in this study exhibited significantly enhanced chiral recognition capability, and baseline separation (Rs≥1.5) of 10 racemates of amino acid derivatives was achieved.

Immobilized artificial membrane (IAM) chromatography is a vital technique for studying drug-biomembrane interactions, predicting drug permeability, and facilitating drug screening. However, its broader application is hindered by the limited commercial availability of IAM columns, their susceptibility to aging or premature failure, and the complexity of preparation process. In this study, a novel strategy for fabricating IAM stationary phases was developed via atom transfer radical polymerization (ATRP). Using 12-methacryloyl dodecylphosphatidylcholine (MDPC) as a phospholipid functional monomer, this proposed approach enables the in-situ growth of a uniform phospholipid polymer coating on silica surfaces, which not only effectively protects the silica matrix from aggressive acidic or basic mobile phases, but also effectively simulates the phospholipid microenvironment of cell membranes. The resulting IAM stationary phase showed excellent chemical stability over a wide pH range (2.0∼10.0). The evaluation of 62 drugs revealed a strong correlation (Spearman correlation coefficient = 0.83) between the CHI IAM values obtained from our self-prepared IAM stationary phase and a commercial IAM column. This close agreement demonstrates that our novel phase can reliably mimic commercial IAM columns, thereby showing its potential applicability in key pharmaceutical scenarios, such as predicting drug transmembrane permeability, for which commercial IAM columns are standardly employed. This provides a new idea for the development of high-performance bionic chromatographic materials and lays an important foundation for the subsequent research and development of different types of IAM stationary phases.