Preparation of "click" binaphthyl stationary phase and its application for separation of anthraquinones from Rheum palmatum L

An organosilane containing binaphthyl functional group was synthesized by clicking 2,2'-bis(prop-2-ynyloxy)-1,1'-binaphthyl with 3-azidopropyltriethoxysilane (AzPTES). The "click" binaphthyl stationary phase was then synthesized by covalently bonding the organosilane onto silica beads. In this synthetic method, the residue of copper iodide (CuI) catalyst can be controlled at a very low level. Polycyclic aromatic hydrocarbons (PAHs) were well retained on the "click" binaphthyl column, and showed different retention factors (k) and separation ratio (α) values from those on octadecylsilyl (ODS) column due to the π-π interaction between the analytes and the stationary phase. The anthraquinone compounds in Rheum palmatum L. were selectively separated and enriched into a fraction by the "click" binaphthyl column. By using this way, the complexity of the sample was largely reduced. Twelve of anthraquinones were recognized by UPLC-ESI-MS/MS. This stationary phase will be very useful for separating and enriching similar compounds with planar aromatic structures from complex traditional Chinese medicine (TCM) samples.     

Selective enrichment of glycopeptides for mass spectrometry analysis using C18 fractionation and titanium dioxide chromatography

Comprehensive glycoprotein characterization based on mass spectrometry (MS) is challenging because of low concentration of glycopeptides and suppression effect of abundant non-glycosylated peptides in MS. Therefore, it is vital to enrich glycopeptides before MS analysis. A new method was developed to selectively enrich glycopeptides from complex sample by coupling C18 fractionation with titanium dioxide (TiO(2)) enrichment. The new method allows to selectively enrich N-linked glycopeptides with various glycan forms and different sequence lengths. Compared with single TiO(2) method, the established method demonstrated higher glycopeptide selectivity and higher glycosylation heterogeneity coverage. Further application of this method to mixture of non-glycosylated protein and glycoprotein digests at different levels reveals the feasibility of enrichment of tryptic glycopeptides from simple proteomics samples.     

High-performance purification of quaternary alkaloids from Corydalis yanhusuo W. T. Wang using a new polar-copolymerized stationary phase

An efficient method for purification of alkaloids from Corydalis yanhusuo W. T. Wang using HPLC was developed, featuring a polar-copolymerized stationary phase named C18HCE. As ionizable solutes, the crude alkaloid sample often suffered from serious peak tailing problem on conventional RP-LC columns, and the separation would rapidly became destroyed with the increasing of load amount. However, on the new stationary phase, good peak shapes (asymmetry factor <1.5) as well as good loadability were easily obtained in a commonly used acidic mobile phase condition. The loading amount could reach 10 mg per injection on an analytical C18HCE column for laboratory-scale purification. About 6.8 mg of palmatine (HPLC purity >98%) and 44.4 mg of dehydrocorydaline (HPLC purity >98%) were rapidly derived from 200 mg of the crude alkaloid sample, and the recoveries of these two compounds were 76.5 and 81.7%, respectively. The purified alkaloids were characterized by comparing retention times with standard compounds as well as (1)H-NMR data. The new method is simple and high yielding, and it may provide a promising tool for purification of alkaloids as well as other alkaline compounds.     

基于亲水作用色谱的寡糖色谱分离新进展

亲水作用色谱(HILIC)作为一种分离极性化合物的液相色谱模式,可以作为反相液相色谱的重要补充,解决极性化合物的分离问题。近几年,HILIC研究发展十分迅速,应用领域也不断拓展,其中寡糖分离是HILIC最典型的应用领域。HILIC适合分离强极性和亲水性样品,是寡糖分离的理想色谱模式。基于HILIC的寡糖分离技术发展迅速,本文以近期发表在主要国际刊物的几个工作为典型案例,介绍HILIC用于寡糖色谱分离的若干进展。     

Comprehensive HILIC × RPLC with mass spectrometry detection for the analysis of saponins in Panax notoginseng

A comprehensive off-line two-dimensional liquid chromatography (2D-LC) method coupling hydrophilic interaction liquid chromatography (HILIC) and reversed phase liquid chromatography (RPLC) was developed in this study to detect as many saponins as possible in extracts of Panax notoginseng. The orthogonality of the 2D HILIC × RPLC was up to 81%, and the peak capacity was 10200. In total, 224 saponins were found, and some of them were trace amounts. Besides, a screening table designed by adding molecular weights of possible aglycones and sugars was constructed to help rapidly characterize the saponins using MS information. Unfortunately, the structure of saponins could not be identified by using only MS information.     

改进的QuEChERS方法用于鱼肉中孔雀石绿、隐色孔雀石绿、结晶紫和隐色结晶紫的快速检测(英文)

孔雀石绿（MG）和结晶紫（CV）具有抗菌等活性,常被违法用于水产养殖业。但MG、CV及其代谢产物隐色孔雀石绿（LMG）、隐色结晶紫（LCV）具有致癌性。所以水产品中染料的残留检测是食品安全分析的重要问题。由于水产品基质复杂,样品前处理尤为重要。本文发展了一种基于QuEChERS技术与高效液相色谱联用的方法,用于鱼肉中4种染料的同时检测。对QuEChERS方法中提取剂体积、提取次数以及分散固相萃取材料进行了优化。结果表明反相/强阴离子交换材料（C18SAX）能有效提高回收率。在最优条件下,4种染料在0.5~100 mg/L范围内线性良好,相关系数均大于0.998。该方法在鱼肉中的回收率为73%~91%,RSD为0.66%~5.41%。结果表明该方法简单、高效,适合于鱼肉中染料的快速检测。     

基于部分酸水解-亲水作用色谱-质谱的黄芪多糖结构表征

来自中药的水溶性多糖具有广谱治疗和低毒性特点,是天然药物及保健品研发中的重要组成部分。针对中药多糖结构复杂、难以表征的问题,本文以中药黄芪中的多糖为研究对象,采用"自下而上"法完成对黄芪多糖的表征。首先使用部分酸水解方法水解黄芪多糖,分别考察了水解时间、酸浓度和温度的影响。在适宜条件(4 h、1.5 mol/L三氟乙酸、80 ℃)下,黄芪多糖被水解为特征性的寡糖片段。接下来,采用亲水作用色谱与质谱联用对黄芪多糖部分酸水解产物进行分离和结构表征。结果表明,提取得到的黄芪多糖主要为1→4连接线性葡聚糖,水解得到聚合度4~11的葡寡糖。本研究对其他中药多糖的表征具有一定的示范作用。     

A multifunctional dual membrane electrodialytic eluent generator for capillary ion chromatography

A multifunctional electrodialytic generator (EDG) for capillary ion chromatography (CIC) is described. The same device can generate acidic, basic or saline eluents. Two oppositely charged ion exchange beads are used to fabricate the EDG; the dual ion exchanger configuration ensures the production of gas-free eluent, obviating the need of a gas removal device used with single ion exchanger EDG's. The ability of the same EDG to produce different eluents is governed solely by the choice of the respective feed solutions; this is presently demonstrated by generation of diverse eluents such as Na₂CO₃/NaHCO₃, CH₃SO₃H, and KNO₃. The EDG is implemented simply in a commercial cross fitting and has been tested up pressures to 2000 psi. Under typical operating conditions, the zero current concentration (open circuit penetration, OCP) is negligible. The generated eluent concentration linearly increases with applied current with a slope that is essentially Faradaic. The device permits both isocratic and gradient operation with good reproducibility, as demonstrated by the analysis of anions using HCO₃⁻/CO₃²⁻ EDG.     

Pd/ZSM-5/MCM-41催化剂加氢脱硫性能研究

本工作将三种材料：全硅MCM-41 （Si-MCM-41）、通过机械混合Si-MCM-41和HZSM-5得到的Z-MCM-41-M、通过在HZSM-5外部包覆Si-MCM-41制备得到的Z-MCM-41,采用XRD、N₂吸附-脱附、NH₃-TPD、Py-IR手段进行了表征.分别以这些材料为载体,制备出负载型贵金属Pd催化剂,以二苯并噻吩（DBT）为模型化合物,在固定床反应器上进行加氢脱硫（HDS）性能考察.反应结果表明,载体的表面积或分散程度并不是影响负载型Pd催化剂HDS性能的关键性因素,催化剂的HDS性能受到载体的孔尺寸和载体的酸性双重影响.负载在酸性载体上表现出较好的HDS性能和加氢选择性,与溢流氢有关.其中,在三种催化剂中,Pd/Z-MCM-41催化剂表现出最高的HDS活性和优异的加氢活性,说明在载体的介孔孔道结构中引入微孔的酸中心对提高加氢脱硫活性有重要影响,仅靠机械混合方式制备的载体不能将介孔的孔道优势与微孔的酸性优势表现出来,不能产生较好的协同催化作用,具有介孔孔道结构和适中酸性的Z-MCM-41复合材料是潜在的贵金属加氢脱硫催化剂载体.