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1.
Meropenem, a representative β-lactam antibiotic, is widely used to treat complicated and serious infections. Therefore, it is of great significance to monitor the plasma drug concentration for individualized antimicrobial therapy. This study first describes the development and validation of high-performance liquid chromatography–tandem mass spectrometry cubed method for monitoring meropenem in human plasma. Protein precipitation with methanol and a chromatographic analysis time of 7 min make this method simple and of high throughput. Meropenem was extracted from human plasma with recoveries >94.1%. Calibration curves were linear (R> 0.995) in the concentration range of 0.5–50 μg/mL. Overall accuracy and precision did not exceed 8.0% as well as no significant matrix effect was observed. The novelty of this method is that the triple-stage mass spectrometry technology improves the selectivity and sensitivity. A comparison of the presented method and traditional liquid chromatography–tandem mass spectrometry method was assessed in 44 patients treated with meropenem and Passing–Bablok regression coefficients and Bland–Altman plots showed that no significant difference between the two methods. So the triple-stage mass spectrometry method developed in this study is appropriate and practical for the monitor of meropenem in the daily clinical laboratory practice.  相似文献   
2.
采用水热-煅烧法制备Cd2SnO4,之后通过超声混合法得到一系列MoS2/Cd2SnO4复合材料。采用X射线衍射、扫描电子显微镜、X射线光电子能谱对Cd2SnO4和一系列MoS2/Cd2SnO4复合材料进行结构和形貌的表征。研究了MoS2掺杂量对于MoS2/Cd2SnO4复合材料的气敏性能影响。实验结果表明,当MoS2与Cd2SnO4的质量比为2.5%,MoS2/Cd2SnO4复合材料制备的气敏元件在170 ℃时对浓度为100 μL·L-1的甲醛气体的灵敏度为40.0,最低检测限为0.1 μL·L-1。  相似文献   
3.
The chiral separation of various analytes (dichlorprop, mecoprop, ibuprofen, and ketoprofen) was demonstrated with different cyclodextrins as mobile phase additives in open-tubular liquid chromatography using a stationary pseudophase semipermanent coating. The stable coating was prepared by a successive multiple ionic layer approach using poly(diallyldimethylammonium chloride), polystyrene sulfonate, and didodecyldimethyl ammonium bromide. Increasing concentrations (0–0.2 mM) of various native and derivatized cyclodextrins in 25 mM sodium tetraborate (pH 9.2) were investigated. Chiral separation was achieved for the four test analytes using 0.05–0.1 mM β-cyclodextrin (resolution between 1.11 and 1.34), γ-cyclodextrin (resolution between 0.78 and 1.27), carboxymethyl-β-cyclodextrin (resolution between 1.64 and 2.59), and 2-hydroxypropyl-β-cyclodextrin (resolution between 0.71 and 1.76) with the highest resolutions obtained with 0.1 mM carboxymethyl-β-cyclodextrin. %RSD values were <10%. This is the first demonstration of chiral open-tubular liquid chromatography using achiral chromatographic coatings and cyclodextrins as mobile phase additives.  相似文献   
4.
A new approach for the evaluation of chiral purity of serine esterification products bearing long-chain alkyl substituents was developed. The compounds were simply converted to aryl-substituted oxazolines which: (i) facilitates effective chromatographic enantioseparation and (ii) enables direct detection using ultraviolet absorption. The method employs a polysaccharide-based chiral stationary phase and allows enantioseparation of highly stable oxazoline products in less than 6 min using a simple binary mobile phase. As opposed to the previously used normal phase method the developed method was performed in the reversed-phase mode. Aside from the benefits of switching to less hazardous solvents with regard to the principles of Green Chemistry, this has also led to a reduction in the analysis time. In comparison with known serine chromophores, the best enantioseparation of aryloxazoline rigid structure may be achieved only based on non-polar interactions with the chiral stationary phase. In contrast, the substitution of the chromophore moiety with hydroxyl substituent affected intra and intermolecular interactions that caused enantioseparation differences. Concurrently, we found high chirality retention of (R)- and (S)-configuration oxazoline standards (≥99% enantiomeric excess) during the introduction of the ultraviolet label. The method is suitable for rapid injection of the mixture containing the ultraviolet absorption marker without prior purification.  相似文献   
5.
Ginkgolide B is a dietary diterpene with multiple pharmacological activities. However, current research on ginkgolide B is not comprehensive. The current study analyzed the metabolic profile of ginkgolide B in vivo and in vitro using ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry. To detect and identify the different metabolites in ginkgolide B, a novel data processing method was used as an assistant tool. A total of 53 different metabolites of ginkgolide B (38 phase I metabolites and 15 phase II metabolites) were detected relative to blank samples. The biotransformation route of ginkgolide B was identified as oxidation, dehydroxylation, hydrogenation, decarbonylation, demethylation, sulfate conjugation, glucose conjugation, methylation, and acetylation. The current study demonstrated a method for rapidly detecting and identifying metabolites and provided useful information to further characterize the pharmacology and mechanism of ginkgolide B. A method for the analysis of other diterpene metabolic components in vivo and in vitro was also established.  相似文献   
6.
二维液相色谱(2D-LC)因具有较高的峰容量,在复杂样品的分离分析中获得了广泛的关注。然而,制备型2D-LC以纯化高纯单体为目标,在方法开发和设备构成等方面与分析型2D-LC有较大的不同,目前尚未得到充分的开发,在大规模的制备纯化中应用较少。本文以一套制备液相色谱模块为分离系统,以稀释泵、切换阀和捕集柱阵列为接口,构建了新型的制备型2D-LC系统,旨在规模化纯化多个活性成分。以烟叶中可以用作医药原料的烟碱、绿原酸、芦丁和茄尼醇等组分为目标物,考察了不同类型填料对样品的捕集效率、过载条件下的色谱保留行为等,优化了制备色谱条件。进而利用在线2D-LC系统实现了烟叶提取物的纯化,通过一次运行获得了4个高纯化合物。该系统具有中压色谱纯化成本低、系统在线运行自动化程度高、稳定性好及容易放大等优点。烟叶中活性化学成分的回收利用对促进烟草行业的发展及带动地方农业经济开发具有重大的意义。  相似文献   
7.
Juglandis Mandshuricae Cortex is the bark of Juglans mandshurica Maxim., which has been used as a folk medicine plant in China and India. In this study, an ultra-high performance liquid chromatography–quadrupole/orbitrap high-resolution mass spectrometry method was developed to clarify and quantify the chemical profiling of Juglandis Mandshuricae Cortex rapidly. A total of 113 compounds were characterized. Among them, seven flavonoids were simultaneously quantified in 15 min, including myricetin, myricetrin, taxifolin, kaempferol, quercetin, quercitrin, and naringenin. The method was validated for accuracy, precision, and the limits of detection and quantification. All calibration curves showed a good linear relationship (r > 0.9990) within test ranges. The intra- and inter-day relative standard deviations were less than 2.16%. Accuracy validation showed that the recovery was between 95.6 and 101.3% with relative standard deviation values below 2.85%. The validated method was successfully applied to determine the contents of seven flavones in Juglandis Mandshuricae Cortex from seven sources and the contents of these places were calculated respectively. This method provides a theoretical basis for further developing the medicinal value of Juglandis Mandshuricae Cortex.  相似文献   
8.
DNA G-quadruplexes (G4s) are key structures for the development of targeted anticancer therapies. In this context, ligands selectively interacting with G4s can represent valuable anticancer drugs. Aiming at speeding up the identification of G4-targeting synthetic or natural compounds, we developed an affinity chromatography-based assay, named G-quadruplex on Oligo Affinity Support (G4-OAS), by synthesizing G4-forming sequences on commercially available polystyrene OAS. Then, due to unspecific binding of several hydrophobic ligands on nude OAS, we moved to Controlled Pore Glass (CPG). We thus conceived an ad hoc functionalized, universal support on which both the on-support elongation and deprotection of the G4-forming oligonucleotides can be performed, along with the successive affinity chromatography-based assay, renamed as G-quadruplex on Controlled Pore Glass (G4-CPG) assay. Here we describe these assays and their applications to the screening of several libraries of chemically different putative G4 ligands. Finally, ongoing studies and outlook of our G4-CPG assay are reported.  相似文献   
9.
Xi-Lin Bai 《中国物理 B》2022,31(5):53301-053301
As a model molecule of actinide chemistry, UO molecule plays an important role in understanding the electronic structure and chemical bonding of actinide-containing species. We report a study of the laser-induced fluorescence spectra of the U16O and U18O using two-dimensional spectroscopy. Several rotationally resolved excitation spectra were investigated. Accurate molecular rotational constants and equilibrium internuclear distances were reported. Low-lying electronic states information was extracted from high resolution dispersed fluorescence spectra and analyzed by the ligand field theory model. The configuration of the ground state was determined as U2+(5f37s)O2-. The branching ratios, and the vibrational harmonic and anharmonic parameters were also obtained. Radiative lifetimes were determined by recording the time-resolved fluorescence spectroscopy. Transition dipole moments were calculated using the branching ratios and the radiative lifetimes. These findings were elucidated by using quantum-chemical calculations, and the chemical bonding was also analyzed. The findings presented in this work will enrich our understanding of actinide-containing molecules.  相似文献   
10.
姬超  李拓  邹晓峰  张璐  梁春军 《化学进展》2022,34(9):2063-2080
有机-无机杂化卤化物钙钛矿太阳能电池(perovskite solar cells, PSCs)由于其成本低廉、制备工艺简单、光电转换率高等优点引起了越来越多的关注,在下一代半导体光伏技术中显示出巨大的发展潜力。然而PSCs器件在商业化生产应用之前,必须解决某些关键问题,例如器件在湿度、光照和过热条件下缺乏稳定性,性能会急剧衰退。层状二维(two-dimensional, 2D)钙钛矿由于其优异的环境稳定性而受到研究人员的广泛关注。通过引入不同种类的疏水性大体积有机铵阳离子可以在钙钛矿体内形成稳定的2D结构。然而,由于绝缘有机间隔阳离子的存在,使其电荷输运能力受阻并影响光电转换性能。本文根据不同种类2D钙钛矿光伏器件的发展进程,总结了影响2D钙钛矿结构和性能的关键问题,如晶体垂直取向设计、量子阱调控和有机层间隔阳离子替换工程等。最后对2D PSCs的未来发展进行展望。  相似文献   
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