离子色谱-抑制电导法测定硫酸镁钠钾口服用浓溶液中镁、钠、钾离子

目的 建立离子色谱–抑制电导法同时测定硫酸镁钠钾口服用浓溶液中镁、钠、钾离子的方法。方法 采用Dionex IonPac^TM CS12A色谱柱（250 mm×4 mm）,Dionex IonPac^TM CG12A保护柱（50 mm×4 mm）;以甲烷磺酸溶液为洗脱液,梯度洗脱,体积流量为1.0 mL/min,柱温30 ℃,检测池温度35 ℃,电导检测器,抑制器为Dionex CDRS 600 4 mm,电流值117 mA,进样体积为25 μL。结果 镁在0.72～1.08μg/mL、钠在12.80～19.20 μg/mL、钾在3.20～4.80 μg/mL线性关系良好,平均回收率分别为101.0%、100.7%、102.9%,RSD值分别为1.4%、1.4%、0.7%。结论 该方法简单、快速、准确,能够有效地控制硫酸镁钠钾口服用浓溶液中镁、钠、钾离子。     

Systematic screening and structural characterization of dipeptides using offline 2D LC-LTQ-Orbitrap MS: A case study of Cordyceps sinensis

Cordyceps sinensis (C. sinensis) is a widely used and highly valuable traditional Chinese medicine. Several dipeptides have been detected in C. sinensis, but current scientific knowledge of its chemical makeup remains limited. In this study, an improved approach that integrates offline two-dimensional liquid chromatography (2D LC) separation, precursor ion list, library screening, and diagnostic ion filtering was established to systematically screen and characterize dipeptides in C. sinensis. Offline 2D LC integrating hydrophilic interaction LC and reverse phase separations was established to eliminate interference and identify the target dipeptides. A library containing the potential 400 dipeptides was created, and a precursor ion list with all theoretical precursor ions was adopted to trigger the MS/MS scan with high sensitivity. To identify dipeptides, the type and connection sequence of amino acids were determined according to the product ions. Ile and Leu residues were differentiated for the first time according to the characteristic ion at m/z 69.07. Ultimately, 170 dipeptides were identified or tentatively characterized from C. sinensis, and most are reported for the first time in this species herein. In addition, the identified dipeptides were also applied for discrimination among the three Cordyceps species, and 11 markers were identified. The obtained results provide a deeper understanding of the chemical basis of C. sinensis.     

Modifying current thin-film microextraction (TFME) solutions for analyzing prohibited substances: Evaluating new coatings using liquid chromatography

For identifying and quantifying prohibited substances, solid-phase microextraction (SPME) continues to arouse interest as a sample preparation method. However, the practical implementation of this method in routine laboratory testing is currently hindered by the limited number of coatings compatible with the ubiquitous high-performance liquid chromatography (HPLC) systems. Only octadecyl (C₁₈) and polydimethylsiloxane/divinylbenzene ligands are currently marketed for this purpose. To address this situation, the present study evaluated 12 HPLC-compatible coatings, including several chemistries not currently used in this application. The stationary phases of SPME devices in the geometry of thin film-coated blades were prepared by applying silica particles bonded with various functional ligands (C₁₈, octyl, phenyl-hexyl, 3-cyanopropyl, benzenesulfonic acid, and selected combinations of these), as well as unbonded silica, to a metal support. Most of these chemistries have not been previously used as microextraction coatings. The 48 most commonly misused substances were selected to assess the extraction efficacy of each coating, and eight desorption solvent compositions were used to optimize the desorption conditions. All samples were analyzed using an HPLC system coupled with triple quadrupole tandem mass spectrometry. This evaluation enables selection of the best-performing coatings for quantifying prohibited substances and investigates the relationship between extraction efficacy and the physicochemical characteristics of the analytes. Ultimately, using the most suitable coatings is essential for trace-level analysis of chemically diverse prohibited substances.     

基于UPLC技术测定栀子主要有效成分及特征指纹图谱研究

目的：为进一步提升栀子药材的质量评价方法,该文建立了同时测定栀子药材中4个主要有效成分（京尼平苷酸、栀子苷、西红花苷-Ⅰ、西红花苷-Ⅱ）含量检测方法。方法：采用超高效液相色谱法,Waters Acquity UPLC BEH-C₁₈色谱柱（2.1mm×100mm,1.7μm）,以乙腈（A）-0.1%甲酸水溶液（B）为流动相,梯度洗脱,流速0.3mL·min^-1;检测波长分别为240nm、440nm。在优化的色谱条件下,4个有效成分浓度在0.0065-96μg·mL^-1范围内线性关系良好,相关系数（R²）不低于0.9995,检测限为0.0386-0.1875μg·mL^-1。结果：对不同产地12批栀子药材的含量测定表明,不同产地栀子药材中4个成分的含量存在较大差异,其中栀子苷、西红花苷-Ⅰ含量分别为2.44%-6.96%、1.26%-3.04%。同时利用ChemPattern软件构建了12批栀子药材的特征指纹图谱,并采用多元统计方法（相似度SA、主成分分析PCA和聚类分析HCA）对不同样品测定结果进行了分析和探讨。结论：所建立的方法为栀子药材及饮片的质量评价和控制提供了参考。     

侧柏叶煮散饮片煎煮质量评价

目的：对比侧柏叶煮散饮片与市售原饮片煎煮质量。方法：应用ITS2序列作为DNA条形码对侧柏叶进行分子鉴定,采用化学指纹图谱表征药材化学组成,评价市售饮片及精准煮散饮片的相似度,测定指标成分槲皮苷的含量,标定指纹图谱共有峰。同时,采用标准汤剂煎煮法,比较市售饮片及精准煮散饮片的煎煮效率,对煮散体系进行综合评价。结果：ITS2序列对侧柏叶药材可实现准确鉴定。与原饮片比较,煮散饮片煎煮效率有所增加,且指纹图谱相似度有所提高,但按标准汤剂煎煮法,煮散饮片出膏率增加20%左右,指标性成分槲皮苷的含量未有显著增长,其余化学成分的煎出率也没有明显变化。结论：精准煮散饮片在一定程度上有利于提高侧柏叶的煎煮效率及药材均一性。     

高速逆流色谱在快速筛选中药天然产物活性成分中的应用

高速逆流色谱结合快速生物活性检测方法,特别适合从中药和天然产物中筛选活性成分。结合本课题组的研究和近年研究进展,本文综述了高速逆流色谱在中药和天然产物中快速筛选活性成分的应用进展。     

Characterization of a robust serine protease from Bacillus subtilis K‐1

Process apt microbial proteases due to their wide range industrial applications have become the focus of intense scientific research during recent years. Considering the hostile process milieu, the proteases intended for application must be robust enough to withstand the extremes of temperature and pH, and presence of organic solvents and other potential enzyme inhibitors. Current study presents the characterization of a robust protease from a previously isolated bacterium Bacillus subtilis K‐1 (BSK‐1). Purification of BSK‐1 protease (5.21‐fold) was achieved to homogeneity by salt (ammonium sulfate) precipitation, and ion‐exchange (diethyl‐aminoethyl‐sephadex) and size exclusion chromatography (Sephadex G‐100). Molecular weight of BSK‐1 protease was determined by SDS‐PAGE analysis (42 kDa). Though the optimum temperature and pH for BSK‐1 protease activity was 50 °C and 10, respectively, but, the protease exhibited remarkable activity and stability over elevated temperatures (60–80 °C) and a broad pH range (pH 7–11). Protease showed resistance towards several organic solvents/other potential enzyme inhibitors. Drastic activity loss in presence of phenylmethylsulfonyl fluoride indicated that the enzyme is a serine protease. Kinetic parameters (K_m and V_max) for BSK‐1 protease were found to be 0.14 mg ml^?1 and 1176 mg min^?1, respectively. Putative amino acid sequence of BSK‐1 protease (derived from nucleotide sequence of protease gene) suggested that the enzyme belonged to peptidases S8/S53 super family with multidomain of S8. BSK‐1 protease being stable under harsh conditions may serve a model system for understanding the molecular basis of stability, and may help designing novel proteases that are suitable for industrial applications.     

Autophagy deficiency in myeloid cells exacerbates eosinophilic inflammation in chronic rhinosinusitis

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Performance of the CRAFTi portable fluorometer comparing with the HPLC method for determining serum retinol

Objective

To determine the performance of a portable fluorometer for measuring serum retinol (SR) concentration.

Design and methods

Serum samples were obtained from 75 factory worker women and 143 school children. SR concentration was quantified using a portable fluorometer (‘CRAFTi’) and HPLC analysis.

Results

SR by HPLC (1.23 ± 0.43 μmol/L) and CRAFTi (1.16 ± 0.46 μmol/L) was significantly correlated. Sensitivity and specificity were 85.3% and 78.0% (cutoff of 1.05 μmol/L). Kappa statistics showed moderate agreement.

Conclusions

CRAFTi portable fluorometer is a promising field-friendly tool for screening vitamin A deficiency.