Journal of separation science最新文献

In this study, in situ electrodeposition of Zn─Al-layered double hydroxides (Zn─Al-LDHs) on the surface of pencil graphite substrate were practiced with interlayer modification by ibuprofen. The prepared composite increases the efficiency of the proposed method by increasing the level of interaction between the sorbent and the selected analytes including acetylsalicylic acid and naproxen (NAP) in real sample. Eventually, the extracted target analytes were injected into high-performance liquid chromatography ultraviolet (HPLC-UV) for their measurement. The experimental design including PBD and BBD was implemented to obtain the maximize efficiency and optimal condition for extraction of the target analytes. Therefore, in optimal conditions, limits of detection of 0.33–0.64 µg L⁻¹, linear dynamic range (LDR) of 1–100 µg L⁻¹ (with r² > 0.9934), and limits of quantification (LOQs) of 1.1–2.1 µg L⁻¹ were obtained for target analytes by SPME-HPLC-UV. The intra-day relative standard deviation (RSD%) were found to range in 3.90%–5.30% (4.90%–6.80%) at concentration of 5–50 µg L⁻¹ (2–10 µg L⁻¹). According to obtained result, the relative recovery was calculated between 90% and 109%. Therefore, the obtained results showed that the selected method has a suitable performance for the preconcentration and extraction of acetylsalicylic acid and NAP in biological samples.

Sulfonamides, the most frequent antibacterial agent, are widely used due to their low cost and excellent antibacterial effect. With the emergence of the environment, the potential hazard to the ecological environment has attracted the great attention of humans. Based on matrix solid-phase dispersion coupled with high-performance liquid chromatography-tandem mass spectrometry, an accurate, fast, and sensitive analytical method was developed for the determination of sulfonamides (SAs) in soil. Several influencing factors including the type of dispersants, the ratio of sample-to-sorbent, eluents, and solvent volume were investigated, and the matrix effects were evaluated. Under optimized conditions, the calibration curves exhibited excellent linearity with correlation coefficients (r) exceeding 0.996. The limit of detection (based on signal-to-noise ratio [S/N] = 3) and limit of quantification (based on S/N = 10) were 0.024–0.058 and 0.079–0.195 µg/kg, respectively. The recoveries ranging from 70.12% to 123.63% were obtained with a relative standard deviation of less than 15% at three levels (20, 40, and 200 µg/kg). The developed method was successfully applied to analyze 13 SAs at trace levels in a real soil sample. This proposed method would be an alternative and suitable for routine application in the future owing to its rapidity, sensitivity, and affordability.

Sanhua Decoction (SHD) is a classic prescription for the treatment of stroke in the clinic. Based on the combination strategy in vitro and in vivo, the chemical constituents of SHD were characterized by ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry, and the metabolites of five effective anthraquinone aglycones (emodin, chrysophanol, rhein, aloe-emodin, and physcion) of rhubarb in SHD were studied. A total of 222 compounds were isolated and identified in vitro, including 50 flavonoids and their glycosides, 41 coumarins, 22 anthraquinones, 22 tannins, 14 phenylpropanoids, 16 alkaloids, 18 organic acids and their esters, 14 lignans, six anthrones, and 19 other compounds. A total of 111 prototype components were isolated and identified in vivo. Among them, 26, 82, 101, and 46 prototype components and 87 metabolites were detected in plasma, urine, feces, and bile for the first time. This study provides a basis for the identification of chemical components in vivo and in vitro and the analysis of potential pharmacodynamic components of SHD, and provides a basis for further study of pharmacodynamic mechanism.

Thrombin was immobilized on magnetic core-shell mesoporous silica nanoparticles (Fe₃O₄@nSiO₂@mSiO₂) for the first time and used to screen enzyme inhibitors from extracts of Notopterygium incisum. The immobilized thrombin was characterized by Fourier-transform infrared spectroscopy, transmission electronic microscopy, thermal gravimetric analysis, and vibrating sample magnetometry. The results demonstrated that the immobilized thrombin possessed good thermal stability and high-temperature resistance for feasible storage and reuse. Two ligands, notopterol (1) and isoimperatorin (2) were fished out from the extract of N. incisum using the immobilized thrombin. They inhibited thrombin with IC₅₀ values of 59.35 ± 1.420 and 107.8 ± 1.660 µM, respectively. This is the first report of thrombin-inhibitory activity associated with notopterol and isoimperatorin. Meanwhile, the inhibition mechanism of both compounds was investigated by enzyme kinetic analysis and molecular docking. The method used enables rapid screening for thrombin inhibitors from medicinal plants, providing an efficient tool for the discovery of anti-thrombotic active compounds.

Guyinjian (GYJ) is a classic traditional Chinese medicine formula for the treatment of polycystic ovary syndrome, ovulation disorders, immuno-sterility, oligomenorrhea with kidney deficiency, and so forth. Due to the unclear chemical components of GYJ, the elucidation of the pharmacological mechanism, and the comprehensive development and utilization of GYJ in clinical is being restricted. In this study, ultra-high-performance liquid chromatography with quadrupole time-of-flight-tandem mass spectrometry combined with the Progenesis QI platform and using reference standards, online and self-built databases matching, fragmentation rules analysis of mass spectrometry peaks, a total of 235 compounds were preliminarily characterized, including 69 flavonoids, 65 terpenoids, 34 phenylpropanoids, 22 saccharides, sugar esters, and glycosides, 15 organic acids, and 30 others. These compounds may reflect the chemical properties of GYJ. The method established in this study can systematically, rapidly, and accurately resolve the chemical components in GYJ, which lays the foundation for further establishment of the pharmacodynamic substance basis and quality control.

Using poly(styrene-divinylbenzene) microspheres as stationary phase matrix and mercaptosuccinic acid as a modifier, a new weak cation exchange resin was synthesized by thiol click reaction. The conditions for thiol-chlorine click reaction and thiol-alkene click reaction were optimized. The surface morphology and chemical composition of the modified microspheres were characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, and an elemental analyzer. The stationary phase can achieve the separation of six common cations within 25 min. A homemade weak cation chromatographic column was used to determine the impurities of Na⁺ and K⁺ and the content of tetramethylammonium ions in tetramethylammonium hydroxide samples. The method showed a good linear correlation in the range of 0.1–500.0 mg/L with correlation coefficients of 0.9998–0.9999, and the limits of detection (signal-to-noise ratio ≥ 3) were 0.01–0.20 mg/L. The intra-day relative standard deviations (RSDs) were in the range of 1.1%–4.4%, and the inter-day RSDs were in the range of 0.8%–14.8%. The spiked recoveries were in the range of 91.92%–119.86%. The results showed that the prepared stationary phase exhibited effective separation ability and good reproducibility, which was suitable for the analysis of the impurities of Na⁺, K⁺, and the content of tetramethylammonium in the tetramethylammonium reagents.

Lipid extraction of complex biological samples is essential for high-quality data in liquid chromatography-mass spectrometry (LC-MS)-based lipidomics. This study introduces a three-phase liquid extraction (3PLE)-ultra-high-performance LC coupled with quadrupole time-of-flight tandem MS method. This method was successfully applied to lipidomics analysis of breast cancer cells, including highly metastatic MDA-MB-231 and slightly metastatic MCF7 cells. The 3PLE method employed an n-hexane/methyl tert-butyl ether/acetonitrile/water solvent system that formed one aqueous and two organic phases. Neutral and polar lipids were enriched in the upper and middle organic phases, respectively, and combined for detection, thereby reducing analysis time. Compared with the Bligh and Dyer method, 3PLE achieved higher sensitivity and detected more features, with over a 50% increase in the relative abundance of nearly 50% of the differential lipids. In total, 21 differential lipids were identified in the MDA-MB-231 group and 22 in the MCF7 group compared to normal breast epithelial cells (MCF10A). Pathway analysis suggested that lipid changes in breast cancer cells were associated with glycerophospholipid metabolism, arachidonic acid metabolism, sphingolipid metabolism, and linoleic acid metabolism. The study presents a highly efficient lipidomics method, providing a scientific foundation for understanding breast cancer pathogenesis and aiding in diagnosis.

A novel and rapid method was developed for the determination of galantamine in human plasma by microchip electrophoresis with a highly integrated contactless conductivity detector (CCD). The instrumental parameters affecting the response of the detector, such as excitation frequency and excitation voltage, were examined and optimized. The electrophoresis conditions that influenced the separation and detection of galantamine, including the composition of buffer solution, buffer pH, buffer concentration, additives, injection time, and separation voltage were systematically investigated. Under the optimal conditions, the peak height had a good linear relationship with the concentration of galantamine in human plasma from 10 to 160 µg/L, and the correlation coefficient was 0.9992, the limit of detection reached 1.1 µg/L. The recoveries were between 98.6% and 102.1%. This sensitive, rapid, and convenient method is a good alternative to existing methods for galantamine determination. Also, this highly integrated CCD holds great promise in clinical biochemical analysis.

This study aims to develop and validate a robust analytical method for the quantification of polybrominated diphenyl ethers (PBDEs) in human serum using gas chromatography–tandem mass spectrometry. We compared procedural blanks, recoveries, and operational convenience of liquid–liquid extraction and supported liquid extraction for the determination of serum PBDEs. We evaluated different extraction solvents for their effect on PBDE recoveries. Supported liquid extraction was selected for method validation due to its operational convenience. The method demonstrated satisfactory linearity, sensitivity, and reproducibility, with the range of 0.10–5.00 µg/L for most PBDE congeners and 0.20–10.0 µg/L for PBDE-154 and PBDE-183, with limits of detection ranging from 2 to 48 ng/L, and with matrix effects ranging from 94% to 113%. Quality control assessments indicated that recoveries ranged from 85% to 110% and relative standard deviations of less than 11%. The proposed method was applied to biomonitoring of 111 healthy adults, revealing detectable levels of PBDEs in over 90% of the samples. BDE-47 and BDE-183 were the most prevalent, with mean concentrations of 4.13 and 22.1 ng/L, respectively. Detection frequencies ranged from 0.90% for BDE-17 and BDE-85 to 25.2% for BDE-47. Males had higher mean concentrations of BDE-183 than females.

Retention index prediction based on the molecule structure is not often used in practice due to low accuracy, the need to use paid software to calculate molecular descriptors (MD), and the narrow applicability domain of many models. In recent years, relatively accurate and versatile deep learning (DL)-based models have emerged. These models are now used in practice as an additional criterion in gas chromatography-mass spectrometry identification. The DB-225ms stationary phase (usually described as 50%-cyanopropylphenyl-50%-dimethylpolysiloxane in available sources) is widely used, but ready-to-use retention index estimation models are not available for it. This study presents such models. The models are linear and use simple constitutional MD and retention indices predicted by DL for the DB-WAX and DB-624 stationary phases as MD (we show that it is their use that allows us to achieve satisfactory accuracy). The accuracy obtained for a completely unseen hold-out test set: root mean square error 73.2; mean absolute error 45.7; median absolute error 22.0. The models were trained using a retention data set of 266 volatile compounds. All calculations can be performed using the convenient open-source software CHERESHNYA. The final equations are implemented as a spreadsheet and a code snippet and are available online: https://doi.org/10.6084/m9.figshare.26800789.