Chromatographia最新文献

In this paper, a mixed-mode monolith was prepared by separately synthesizing hydrophilic and hydrophobic materials at both ends of a chromatography column by a one-step method. The prepared mixed mode monolith was used as solid phase extraction adsorbent for simultaneous enrichment and purification of licorice chalcone A and isoliquiritigenin from licorice combined with high performance liquid chromatography (HPLC). It had superior ability to enrich and purify licorice chalcone A and isoliquiritigenin than single hydrophilic or hydrophobic monolith. The method had good linearity in the range of 0.50–400 μg/mL. The linear regression equation was y = 465.45 ×  − 1.04 and the correlation coefficient was 0.9999. The relative standard deviations (RSDs) of intra-day and inter-day precision were both less than 1.19%. The results showed that the method was simple and accurate, and could be used for the enrichment and purification of licorice chalcone A and isoliquiritigenin from licorice.

As a new carbon nanomaterial, graphene (Gr) has attracted wide attention in the field of separation and analysis because of its large specific surface area and strong hydrophobicity. A highly efficient and selective graphene/SiO₂ (Gr/SiO₂) dispersive solid-phase extraction (d-SPE) material was prepared through electrostatic assembly. This process involved the combination of negatively charged poly (sodium 4-styrenesulfonate) (PSS) mediated GS (denoted as PSS-GS) and positively-charged SiO₂, modified with triethoxy silane amino. The precursor material was characterized using FESEM, FTIR and so on. We evaluated the extraction performance of this new sorbent with eight pesticide residues, using the HPLC–MS method. The sorbent demonstrated excellent recovery rates for the pesticide residues under various frequency of use conditions and pH levels. It showed that the SiO₂ and Gr have synergistic extraction effect, and the composite material has good stability and reusable, Ultimately, this newly developed d-SPE material was successfully applied in the analysis of fruit juice samples, yielding good recovery rates in the range of 82.18 to 117.49%.

Melia. toosendan Sieb.et Zucc., a potent herbal medicine, boasts diverse therapeutic properties. As the main components, the isotoosendanin blocks protective autophagy in chemotherapy-induced cultured cancer cells and xenograft tumor tissue to significantly enhancing anticancer activity, and the fraxinellone contributes to pesticidal activity, anti-inflammatory and immunomodulatory effects. Until now, the metabolic profiles remained unknown. In the present study, 13 metabolites of isotoosendanin and 13 metabolites of fraxinellone were characterized in the blood, urine, and feces of rats by UPLC/ESI/qTOF-MS analysis. Five metabolites (F-M3, F-M5, I-M1, I-M5, I-M8) were fully characterized. The isotoosendanin and fraxinellone were mainly involved in hydrogenation, acetylation, and methylenation metabolic reactions. This is the first study illuminates the two components in vivo metabolism, laying the foundation for future pharmacodynamic and mechanistic investigations. It is necessary to deeply understand the process of drug activation, and deactivation, rationally design new drugs, and guide the research and development of new drugs.

Restricted Access Media-Methacrylic Resin with the ability of protein exclusion was prepared by the free radical polymerization using methacrylic acid, ethylene glycol dimethacrylate and glycidyl methacrylate as monomer, cross-linker and comonomer, respectively. Protein exclusion ability of this material was studied. The results showed that the material was able to eliminate 93.6% of protein after bovine serum albumin solution was added and shaken for 220 min. Adsorption kinetics and adsorption isotherms of Lamotrigine on this material were investigated. The experimental data were the most suitable for the pseudo-second-order kinetics model and Freundlich isotherm model. Restricted Access Media-Methacrylic Resin was used as sorbent for Solid-Phase Extraction to extract Lamotrigine from Human Plasma. The method for the determination of Lamotrigine in human plasma by SPE followed by the HPLC–UV presented linear range from 1.0 to 66.6 µg/mL with correlation coefficient 0.9930 for Lamotrigine, assay precision with relative standard deviation value 6.24%, and assay accuracy 94.7–104.7% with relative standard deviation values 4.33–5.81%. SPEs filled with this material were used at least 7 times without any significant changes in their performance. Analytical validation parameters demonstrated that the method could be applied to the determination of Lamotrigine at the therapeutic plasma levels without other treatments.

The European Union RoHS Directive restricts the presence of phthalate esters, polybrominated diphenyl ethers (PBDEs), and polybrominated biphenyls (PBBs) in electrotechnical products. The international standard IEC 62321-3-3 describes a method of screening for these chemicals using gas chromatography–mass spectrometry with a pyrolyzer/thermal desorption accessory (Py/TD-GC/MS). Although the IEC 62321-3-3 method is effective at determining levels of these restricted compounds in polymers, applying this method in RoHS testing poses two issues: it requires the preparation of a relative response factor (RRF) database from expensive standard mixed solutions, and it has a long analysis time (30 min). In a previous report, we described a method based on a “ready-to-use” RRF database that eliminates preparation of the RRF database. In this report, we resolved the remaining issue by improving the analytical throughput of the IEC 62321-3-3 method. By optimizing the Py/TD and GC/MS conditions, we almost halved the analysis time to 16 min while maintaining analytical accuracy. These optimized conditions were then combined with the above-mentioned “ready-to-use” RRF database to create a new method that resolves both of the issues with the IEC 62321-3-3 method. This new method demonstrated good sensitivity with a lower limit of detection of under 30 mg/kg for each target compound. We also assessed the analytical accuracy of this new method by analyzing various standard polymer materials on two different analytical instruments. On both instruments, the mean recovery rate was within 100 ± 30% for seven phthalate esters and for combined concentrations of PBDE and PBB congeners, which demonstrated that the quantitative accuracy of the new method is sufficient for RoHS testing. The new method resolves the issues with the IEC 62321-3-3 method and offers rapid, simple, and reliable screening that can be adopted for RoHS testing.

This study presents the certification of spinach and kimchi cabbage certified reference materials (CRMs), (KRISS CRM 108-05-010 and 108-05-011), for 5-Me-THF. The fresh spinach and kimchi cabbage process involved washing, freeze-drying, pulverizing, sieving, V-mixing, and bottling in 10-g portions. The 5-Me-THF in the CRMs was then extracted and analyzed using a tri-enzyme method and isotope dilution ultra-performance liquid chromatography/tandem mass spectrometry. The method validation demonstrated that the method was both repeatable and reproducible, with the recovery ranging from 96.5 to 107.2%. The stability monitoring was performed for 7 days at room temperature, 1 month at − 20 °C, and 13 months at − 70 °C, confirming the stability of the CRMs under most conditions. The certified values were (16.93 ± 0.73) mg/kg and (11.66 ± 0.25) mg/kg for spinach and kimchi cabbage CRMs, respectively. The homogeneity of the CRMs was 1.85% and 0.91% for spinach and cabbage CRMs, respectively. Additional long-term stability assessments were performed, and this suggested that the CRMs will remain valid for at least another 48 months at − 70 °C.

Cultivated Arachis hypogaea L., is commonly known as peanut. Its seed coat, also referred to as a shell, plays a critical role in safeguarding the seeds and facilitating the transportation of diverse metabolites. In the current work, an examination of metabolite profiling was executed utilizing UPLC-ESI–MS/MS in the seed coat (SeC), seed skin (SeS), and seed pulp (SeP) of four distinct peanut varieties of different geographical locations in India. The method was also validated according to ICH guidelines. A linear detector response was observed within a concentration range of 0.019–20.0 ng/mL, R² = 0.999. The limit of detection (LOD) and quantification (LOQ) of the targeted compounds were found to be within the range of 0.075–0.426 and 0.227–1.292 ng/mL, respectively. The intra-day and inter-day precision demonstrated relative standard deviation %RSD < 2%. The results of Principal Component Analysis (PCA) have demonstrated that the differentiation between varieties of peanut is attributable to the existence of luteolin and rutin having a greater impact on the identification of varieties.

Graphical Abstract

Iodine value is an essential parameter for assessing the composition and quality of oils. A commonly used method for iodine value determination is the Wijs method. Recently, the HPLC method for assay of iodine monochloride via iodination of 2-chloroaniline with iodine monochloride has been reported. This study presents an approach for iodine value determination by HPLC via quantification of the unreacted iodine monochloride after reaction with oil samples, similar to the back titration approach in the Wijs method. Chromatographic conditions consist of gradient elution using water and acetonitrile on the C18 column with a detection wavelength of 304 nm. Oleic acid, with a known iodine value (83–103 gI/100 g), was used as a method development and validation reference compound. The method was validated as per International Conference on Harmonization guidelines and was accurate (98–102%), robust, and linear (r² = 0.999) for oleic acid ranging from 5 to 20 mg. The repeatability and intermediate precision were within 1%. The validated method was applied for the iodine value determination of 10 cold-pressed oils. Thus, an HPLC method is developed, which offers minimal sample requirements, high accuracy, less manual intervention, and precision for the iodine value determination of oils.

The study aims at developing and validating a RP-HPLC (reverse phase high-performance liquid chromatography) method for the standardization of Maytenus emarginata (Willd.) Ding Hou extract by selecting Lupeol, β-Amyrin, and Stigmasterol as marker compounds. The developed analytical method used a Phenomenex C₈ column (250 × 4.6 mm; 5 μm) and the mobile phase of acetonitrile and HPLC (high-performance liquid chromatography) grade water (85:15) in isocratic elution at the flow rate 2.0 ml/min. Further, the compounds were traced at 202 nm with the run time of 9 min. The calibration curves presented good linear regression (R² > 0.999) in the tested concentrations. The developed method represented good repeatability for the estimation of the three compounds, namely Lupeol (0.009%), β-Amyrin (0.010%), and Stigmasterol (0.011%) in the samples having the RSD (relative standard deviation) of < 2% respectively. For all analytes, percentage recovery surpassed 90%. The validated RP-HPLC Method was utilized to quantify Lupeol, β-Amyrin, and Stigmasterol from methanolic extract of aerial parts of Maytenus emarginata (Willd.) Ding Hou.