高效分离糖及糖和糖甙的α-、β-差向异构体的新型柱——β-环糊精化学键合相柱

]β-环糊精化学键合相色谱柱用于分离糖、糖醇,糖与糖甙的α-和β-差向异构体有好的分离效果。在室温,常规洗脱分离糖,大多数不存在差向异构体的分离。分离一些糖的差向异构体,在0℃有更好的效果。多种溶剂体系,如乙腈/水、丙酮/水,乙酸乙酯/甲醇/水、乙醇/正己烷等都可有好的分离效果。所有的分离都为正相体系。柱效和柱的稳定性均很好。如果使用uv检测器的低波长端（如195nm,以乙腈/水为移动相,不仅可用之检测糖,还可作梯度洗脱。     

西他沙星差向异构体的毛细管电泳分离

以γ-环糊精和D-苯丙氨酸为手性选择剂,采用毛细管区带电泳成功地分离了新型抗菌素西他沙星差向异构体。考察了添加剂的种类、浓度和缓冲溶液的pH对毛细管电泳分离西他沙星的影响。分离电压为15 kV,选用60 cm(有效长度52.5 cm)×50 μm i.d.的石英毛细管,缓冲溶液组成为10 mmol/L KH2PO4-K2HPO4(pH 4.5),10 mmol/L CuSO4,20 mmol/L γ-环糊精和 10 mmol/L D-苯丙氨酸。实验结果表明,添加剂的种类和浓度是影响西他沙星手性分离的重要因素,只有当 D-苯丙氨酸、铜离子和γ-环糊精同时存在并达到一定浓度时,西他沙星差向异构体在毛细管电泳中才具有良好的分离效果。该方法可用于西他沙星差向异构体的定量分析。     

牛蒡叶中微量木脂体牛蒡子甙和牛蒡子甙元的分离与鉴定

 建立了分离鉴定牛蒡叶中微量木脂体牛蒡子甙(arctiin)和牛蒡子甙元(arctigenin)的方法。牛蒡叶粗提物经聚酰胺柱提取,浓缩其甲醇洗脱液并于低温下静置析出白色沉淀物。沉淀物用甲醇溶解后经反相高效液相色谱(RP-HPLC)分离,纯化得到两个主要组分。经紫外光谱(UV)、红外光谱(FTIR)及电喷雾质谱(ESI-MS)检测,并与牛蒡子甙和牛蒡子甙元对照品的UV,LC-ESI-MS,HPLC及FTIR图谱比较,鉴定两个主要成分为牛蒡子甙和牛蒡子甙元。     

亚叶酸钙差向异构体的毛细管电泳分离分析

亚叶酸钙在临床治疗肿瘤中与甲氨蝶呤合用可提高人体对甲氨蝶呤耐受性,它有两个手性中心：(1)分子的谷氨酸部分;(2)位于蝶啶环的6位C原子上。由于采用L-谷氨酸原料合成,分子中谷氨酸部分的手性碳处于光学纯状态,使亚叶酸钙一般以差向异构体混合物的形式使用。临床实验证明(6S)-异构体具有更显著的药理作用,且毒性低。需要获     

含羟基的青蒿倍半萜内酯差向异构体的合成

本文报道以青蒿酸(2)为原料合成了一些含羟基的青蒿倍半萜内酯差向异构体9与10、11与12、13与14。其中9已从青蒿中分离到。     

鬼臼毒素类4位差向异构体的HPLC研究

八对鬼臼类木脂素类化合物,其中包括有五对为稳定氮氧自由基自旋标记的鬼臼类化合物被用高效液相色谱(HPLC)在C-18反相柱上得到很好的分离.并对它们的保留时间和行为进行了研究.结果表明,甲醇对于分离这些差向异构体是必须的,而加入乙腈对含某些官能团的衍生物是很有效的.     

HPLC法同时测定刺五加注射液中刺五加甙B和甙E的含量

利用ＨＰＬＣ梯度洗脱法同时测定刺五加注射液中刺加甙五加甙Ｅ的含量,试验证明本法快速,灵敏、简便、准确。     

芳香环状低聚体的结构表征

综述了芳香环状低聚体结构表征的发展过程及最新进展,以高效液相色谱、快原子（离子）轰击质谱、激光质谱、电喷雾质谱为主结合其他辅助方法分别做以介绍并比较了各种表征方法的特点及应用范围。     

液相色谱-电喷雾电离质谱与电子轰击质谱联用筛选百合中的甾体皂甙

 利用高效液相色谱 电喷雾电离质谱联用仪 (HPLC/ESI MS)、电子轰击质谱 (EI MS)和半制备型高效液相色谱 ,从卷丹百合中筛选出了两种甾体皂甙 ,其中一种为含有 3个糖基与提果皂甙元的甾体皂甙 ,另一种为含有 3个糖基和薯蓣皂甙元的甾体皂甙。结果表明 :在线的HPLC/ESI MS能够准确快速地提供糖甙类化合物的分子质量和糖链部分的有益信息 ,但对甙元部分提供的信息极少 ;离线的EI MS只需极少量 (1mg～ 2mg)的纯品就能准确地提供甙元部分的有益信息 ,但很难获得糖甙的分子离子峰与糖链部分的信息 ,两者有机地结合起来能快速地从植物中筛选甾体皂甙。     

中性富勒烯分子的直接电喷雾质谱分析

电喷雾电离是新近发展的一种质谱技术, 适用于分析在溶液中呈离子状态的物质, 具有无碎片的特点。本文根据富勒烯分子的电子亲和性能, 将富勒烯混合物的甲苯溶液直接进行电喷雾质谱分析, 检出了C60, C70, C76, C80, C82, C84, C86,C88, C90, C92, C94和C96等的负离子峰。并用萘钾作还原剂,将富勒烯混合物预先还原, 制得富勒烯负离子溶液后再作电喷雾质谱分析, 得到相同的结果。表明各类富勒烯分子在电喷雾过程中俘获电子的能力与被萘钾还原的能力相一致。     

On the Assignment of Anomeric Configuration

One of the diversities of carbohydrate structure lies in their ability to form different anomers from the monosaccharide unit. Unfortunately, the question of assignment of anomers has not been dealt with properly or accurately in most organic and biochemical textbooks and reference books. In this article, the question of assignment of anomers is examined from several different standpoints and an easy solution for this tricky problem is suggested.     

硝基甲苯与硝基苯甲酸异构体的高效液相色谱法分析

采用KromasilC18柱同时分离了硝基甲苯与硝基苯甲酸异构体。在选定的色谱条件下,硝基甲苯与硝基苯甲酸异构体得到了良好分离。     

番茄中类胡萝卜素及其顺式异构体的HPLC分析

建立了一种能同时快速分离、定性番茄中3种类胡萝卜素及其异构体的高效液相色谱(HPLC)方法。采用正己烷-乙醇(3∶4)对样品进行提取,甲基叔丁基醚+0.05%三乙胺-乙腈+0.05%三乙胺为流动相梯度洗脱,以Carotenoid C30柱(250 mm×4.6 mm i.d.,5μm)进行分离,检测波长为475 nm。结果表明,在优化实验条件下,番茄中有11种类胡萝卜素得到了良好分离,包括3种全反式异构体和8种顺式异构体。叶黄素、β-胡萝卜素、番茄红素分别在0.1~5.0,0.1~20,0.1~100μg/m L浓度范围内线性关系良好,相关系数均在0.99以上,检出限(LOD)分别为0.13,0.12,0.56μg/g,定量下限(LOQ)分别为0.43,0.41,1.88μg/g;日内相对标准偏差(RSD)为1.2%~5.3%,日间RSD为1.9%~7.5%,回收率分别为(88.9±6.1)%~(91.7±3.6)%,(92.3±4.3)%~(94.1±6.3)%,(102.6±4.2)%~(107.1±3.4)%。该方法具有分析时间短、灵敏度高、分离完全等优点,适用于番茄中类胡萝卜素及其顺式异构体的分析测定。     

Analysis for the Isomers of Naphthylamine by Reversed-Phase HPLC with Temperature Controlled

Generally, the analysis of isomers by high performance liquid chromatography (HPLC) requires the liquid-solid adsorption chromatography (LSC) since few satisfactory separations of isomers can be achieved by regular reversed-phase chromatography. Because the moisture absorption from air by the mobile phase will change markedly the separable property of isomers on LSC system, the analysis of isomers by LSC is still a troublesome problem.     

系列烷基甲基萘磺酸盐的高效液相色谱和电喷雾离子化质谱分析

采用反相离子对高效液相色谱(HPLC)和电喷雾离子化质谱(ESI-MS)对系列长链烷基甲基萘磺酸盐(AMNS),包括己基甲基萘磺酸盐、辛基甲基萘磺酸盐、癸基甲基萘磺酸盐、十二烷基甲基萘磺酸盐、十四烷基甲基萘磺酸盐进行分析,通过液相色谱分离条件的优化,找到了最佳分析条件.紫外检测波长230 nm,流动相为甲醇和水混合物,流速为0.8 mL/min,采用梯度洗脱方式进行分析.线性梯度:0～40 min时甲醇-水体积为60:40,在40～70min时,甲醇-水体积比为100:0.样品分离度高,分离效果较好.用面积归一化法得到了样品各组分的相对百分含量.HPLC和ESI-MS是快捷、有效和可靠的分析和表征AMNS的方法.     

在线二维柱切换-超高效液相色谱法同时测定明目地黄丸中莫诺苷、马钱苷、芍药苷、丹皮酚的含量

建立了二维柱切换-超高效液相色谱法同时测定明目地黄丸中莫诺苷、马钱苷、芍药苷、丹皮酚含量的方法.一维色谱柱为Thermo Accucore XL C18(250mm×2.1 mm,4μm),二维色谱柱为DIONEX Acclaimphenyl-1(150mm ×4.6mm,3μm),一维分析流动相为乙腈-水,梯度洗脱,二维分析流动相为乙腈-水,等度洗脱,14.5 min进行阀切换;检测波长:0～14.5 min为240 nm,14.5～ 30 min为275 nm,流速:0.5 mL/min,柱温:30℃.30 min即可完成明目地黄丸中莫诺苷、马钱苷、芍药苷、丹皮酚的含量测定,并有效地将莫诺苷同分异构体分离.莫诺苷、马钱苷、芍药苷、丹皮酚的线性范围分别为7.6 ～ 377 mg/L,9.2～ 459 mg/L,8.4～419 mg,/L和8.2 ～ 409 mg/L,相关系数为0.9999,加样回收率为98.3％～ 100.2％.本方法快捷高效,可对控制明目地黄丸质量提供参考.     

HPLC Separation of Geometric Isomers of Carbamyl Peptides

Abstract

Carbamylated peptides that were studied showed much improved resolution on C-18 reversed phase HPLC columns compared to the parent peptides. A number of dipeptides were carbamylated with ethyl-, n-propyl- or isopropyl isocyanates. The three carbamyl derivatives of each dipeptide could easily be resolved. Carbamylated dipeptides with reversed amino acid sequences were also easily separated. Methionine-enkephalin, leucine-enkephalin, Angiotensins I, II and III and substance P were carbamylated with isocyanates derived from certain carcinostatic 2-chloroethyl nitrosoureas. 1-(2-Chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU), 1-(2-chloroethyl)-3-(cis-4-hydroxycyclohexyl)-1-nitrosourea (cis-4-hydroxy-CCNU) and 1-(2-chloroethyl)-3-(trans-4-hydroxycyclohexy1)-1-nitroso urea (trans-4-hydroxy-CCNU) gave carbamylated derivatives of each peptide and each mixture of derivatives from a single parent peptide could be resolved. Conditions were found in each case whereby baseline resolution of the corresponding cis-4- and trans-4-hydroxycyclohexylcarbamyl peptides was attained. Cyclohexyl-carbamyl peptides were easily separated from the corresponding peptides from hydroxy-CCNUs. Potential applications are discussed. carbamylation in the expression of antitumor activity or toxicity to normal tissues is still not very clear. A number of DNA polymerases (10, 11), DNA ligase (12), glutathione reductase (13), Serine proteases (14, 15) and tubulin polymerization (16) have been shown to be inhibited by carbamylation by nitrosoureas or isocyanates.

The question of whether carbamylation by CENUs and their metabolites is selective to certain enzymes is an important one because nitrosoureas such as CCNU and Methyl-CCNU are converted to antitumor-active metabolites (8, 17, 18). If it is found that the individual metabolites target different proteins, it could have important applications in chemotherapy and drug design.

In order to determine whether such selectivity of carbamylation exists, it was required that analytical methodology be developed that would permit separation of peptides with the same sequence but with different carbamyl groups. These studies offer hope that if peptides with up to 11 aminoacids are carbamylated by CCNU or the 4-hydroxy-CCNUs, one may be able to separate them by HPLC. This limit may be extended if one need only separate cyclohexyl carbamyl peptides from mixtures of geometric and positional isomers of hydroxycyclohexyl carbamyl peptides as might occur in the cell.     

Isomers of uroporphyrin free acids separated by HPLC

A synthetic mixture of uroporphyrin isomers I, II, III and IV as free acids in the synthetic ratio of 1:1:4:2 was resolved by reverse-phase HPLC using a C0:PEL (ODS) 37-50 micron precolumn and a Micro Bondapak C18 analytical column eluted with acetonitrile (4%) in phosphate buffer (pH 6.95). Clinically important I and III isomers of uroporphyrin were readily resolved directly from acidified urine as porphyrin free acids.     

异头效应与“糖”教学中的几个问题

从异头效应这一视角,阐释了构成淀粉和纤维素的葡萄糖结构单元之间α苷键和β苷键的不同及其如何导致结构的悬殊差异。籍此分析了α异头物和β异头物的相对稳定性、淀粉和纤维素酸性水解的难易,指出大自然对食物链的划分是精妙的。     

单纯形优化高效液相色谱法分离测定维生素E的各种异构体

本文用计算机辅助单纯形优化高效液相色谱法分离、测定了精炼植物油副产物中维生索E的各种异构体。探讨了单纯形优化法指导高效液相色谱选择分离的实验条件,并编写了实用的计算机程序。实验结果表明,本法可使比较困难的条件选择工作有章可循,从而提高工作效率。