超临界CO2萃取-高效液相色谱法测定银杏外种皮中银杏酚酸

建立了银杏外种皮中银杏酚酸超临界CO2萃取高效液相色谱的分析方法,使用C18液相色谱柱,以甲醇:水(85:15,V/V)为流动相,在UV310 nm下对其进行了定性定量分析,方法的线性相关系数r=0.99993。加标回收率≥97.5%,RSD小于2%,该方法已用于银杏外种皮中银杏酚酸的萃取检测。     

反相高效液相色谱法测定银杏中银杏酸

采用反相高效液相色谱法测定银杏中5种银杏酸的含量。样品用甲醇为提取溶剂回流提取后定容至25 mL,取2 mL用正己烷从含有硅藻土的pH 2～3溶液进行液-液萃取,上清液真空旋干,加甲醇定容至2 mL后,取20μL进样用Waters Symmetry-C₁₈色谱柱分离,以甲醇-水（88+12,含5%乙酸）为流动相,二极管阵列检测器在波长310 nm处检测。峰面积与5种银杏酸的质量浓度分别在一定范围内呈线性关系,方法的检出限（3S/N）在0.26～1.37 mg·L^-1之间。方法的平均回收率为99.2%,测定值的相对标准偏差（n=5）为6.83%。     

荧光分析法测定银杏酚酸

根据银杏酚酸在紫外光激发下能产生荧光的性质,建立了检测银杏酚酸的荧光分光光度法.以80%乙醇80℃回流8 h提取银杏外种皮,提取液经硅胶柱层析后得酚酸样品.以白果酸为标样,激发波长345 nm、发射波长420 nm测定银杏酚酸.线性回归方程为y=2.5024x+0.4152;线性范围为0.50～100 mg/L,相关系数r=0.9922,相对标准偏差2.6%;检出限0.11 mg/L.     

荧光分析法测定银杏酚酸

根据银杏酚酸在紫外光激发下能产生荧光的性质，建立了检测银杏酚酸的荧光分光光度法。以80％乙醇80℃回流8h提取银杏外种皮，提取液经硅胶柱层析后得酚酸样品。以白果酸为标样，激发波长345nm、发射波长420nm测定银杏酚酸。线性回归方程为，y=2．5024x＋0．4152；线性范围为0．50～100mg／L，相关系数r=0．9922，相对标准偏差2．6％；检出限0．11mg／L。     

银杏酸的分光光度法测定

建立了简便、快速、准确的银杏酸含量的分光光度分析方法。银杏酸粗提物经硅胶柱色谱一次预净化处理后 ,即可在 2 4 2nm或 310nm波长处测定银杏酸。线性回归方程分别为 :A =1.5 5× 10 -4+16 .36C(R =0 .999)或A =0 .0 31+9.0 8C(R =0 .997) ,两者的线性范围均为 6 .0～ 110mg/L。在 2 4 2nm和 310nm两个波长处测定的银杏酸含量都与HPLC法测定结果接近。实验测得了各银杏酸单体的摩尔吸光系数 ,其数值相近。该法简便、快速、准确 ,线性范围宽 ,最低可测至 5 .72mg/L ,可用于银杏酸的定量分析     

薄层扫描法测定银杏外种皮中白果酸含量

报道了一种简单、灵敏、准确测定银杏外种皮中白果酸含量的方法——薄层色谱扫描法。线性范围为1．0～5．0μg／点，纯品的相对标准偏差为1．29％(n=6)，平均回收率为99．7%，方法简便、重现性好。     

高效液相色谱法测定滇白珠植物中滇白珠甙

提出反相高效液相色谱法测定滇白珠甙含量的方法。反相Kromasil C18柱，甲醇－乙腈－水（V／V）＝25：5：70为流动相，紫外220nm检测，外标法定量。线性范围为0.005-0.800g/L，r=0.9997-0.999，方法回收率和标准偏差分别在98.605-102.90%和0.58%-0.69%之间（n=6），3种甙的检测限在0.01-0.02mg/L之间。本方法快速、准确、重现性好，适用于工艺生产中质量控制。     

热辅助下的在线甲基衍生化-气相色谱法分析银杏叶中的银杏酸

采用热辅助下的在线甲基衍生化-气相色谱法测定银杏叶中的银杏酸。银杏叶样品与衍生化试剂四甲基氢氧化铵(TMAH, 25%甲醇溶液)同时进样,在300 ℃的进样口瞬间生成了银杏酸甲基衍生物,银杏叶中6种银杏酸得到很好的分离。在一定的质量浓度范围内银杏酸的线性关系良好,回归系数均大于0.9966,最低检出限范围为0.8～2.8 mg/kg。银杏叶中主要的烷基酚类物质为银杏酸C13∶0,C15∶1和C17∶1,它们的含量(用质量分数表示)分别为11.0%,36.7%和42.8%,3次平行测定的相对标准偏差(RSD)均小于3.4%(n=3)。银杏叶样品中总银杏酸的含量为4.0～10.9 mg/g。该方法无需繁琐费时的衍生化和纯化等前处理步骤,不失为银杏叶中银杏酸测定的一种快速、简便、准确的方法。     

反相银化高效液相色谱法测定银杏叶中银杏酚酸(英文)

 建立了反相银化高效液相色谱测定银杏叶中银杏酚酸含量的分析方法。在样品的浸提液中加入少量酸性盐溶液和吸附剂后 ,用一步反萃取法净化样品 ,有机相浓缩后供HPLC分析。流动相 :V(甲醇 )∶V(体积分数为 5 %的乙酸水溶液 ) =90∶10 ,其中银离子浓度 0 0 3mol·L-1,紫外检测波长 310nm。结果表明 4种银杏酚酸之间达到基线分离 ,该方法平均回收率为97 3% ,相对标准偏差 1 6 % ,最低检测量 0 0 2 6 μg ,可有效地用于银杏叶及其提取物中银杏酚酸的定量分析。     

DLLME-HPLC方法测定银杏叶提取物中银杏酸单体含量

银杏叶提取物(EGB)中的银杏酸(GAs)对渐冻症、癌症和其他一些疑难病症具有独特的疗效。因此,提高液相色谱检测EGB中银杏酸单体的灵敏度和准确度成为探讨EGB药效的重要研究内容。本文以三氯甲烷为分散液液微萃取剂,对EGB试样中的微量GAs进行分散液液微萃取(DLLME)前处理,然后结合高效液相色谱进行检测,从而建立了一种测定EGB中银杏酸单体含量的方法。该方法对EGB中5种银杏酸单体的检出限为0.11～0.22 mg·kg^-1,定量限为0.36～0.74 mg·kg^-1。在5.00 mg·kg^-1加标水平下回收率为94.35%～102.49%。     

微柱液相色谱的研究进展

介绍了微柱液相色谱（μ-LC）。从理论上简单讨论了μ-LC的柱特性、色谱洗脱效应和柱外效应等一系列问题，综述了μ-LC的柱技术的最新进展，讨论了μ-LC对仪器和附件的要求，特别是微流量输液和检测技术，还探讨了μ-LC与多维色谱、质谱等技术的联用。     

反向模式-强阳离子交换-反向模式二维色谱法测定人血浆中甲氨蝶呤浓度

建立了反向模式-强阳离子交换-反向模式(Reversed phase-strong cation exchange-reversed phase)二维色谱平台测定人血浆中甲氨蝶呤浓度的方法。样品经三氯醋酸沉淀蛋白后,在ASTON C8一级柱(100 mm×4.6 mm,5μm)上完成初分离,通过六通阀切换,经ASTON SCX中间级(20 mm×4.6 mm,5μm)二次分离和储存,在SAC C8二级柱(100 mm×4.6 mm,5μm)上完成最后分离,并测定。一级柱流动相为10 mmol/L醋酸铵-乙腈(90∶10,V/V,以醋酸调至p H 3.8),流速为1.0 m L/min;中间级流动相为10 mmol/L H3PO4溶液(p H 3.0);二级柱流动相为50 mmol/L醋酸铵-乙腈(87∶13,V/V,以醋酸调至p H 5.2),流速为1.2 m L/min,检测波长306 nm。单次分析时间4 min,线性范围0.09~5.1μmol/L,检出限为0.005μmol/L,日内RSD小于1.8%,日间RSD小于3.5%,相对回收率99.1%~101.25%,绝对回收率85.7%~86.4%。本方法简便、准确,适合日常血药浓度监测和药代动力学研究。     

Preparation,evaluation, and application of a novel reversed-phase/zwitterionic/hydrophilic interaction liquid chromatographic mixed-mode stationary phase

The present study described the preparation and application of a reversed-phase/zwitterionic/hydrophilic interaction liquid chromatography stationary phase, named as SIL-PS. The SIL-PS was prepared through a four-step reaction, chemical bonding, nucleophilic addition, SN1 substitution, and sulfonation on the silica matrix. It was featured with C₁₂ alkyl chain, quaternary ammonium, tertiary amine, and sulfonate groups. After SIL-PS was packed into the stainless steel column (150?× 2.1 mm i.d.), chromatographic parameters, including acetonitrile content, pH, and ionic strength of the mobile phase, and the column temperature, were systematically investigated to study the retention mechanism. Electrostatic adsorptive/repulsive, partition, and hydrogen-bonding interactions were demonstrated to contribute to the retention. The stability of the SIL-PS was satisfactory, with relative standard deviations of retention factors of 1.93, 2.08, and 1.90% for loxoprofen, adenosine, and liquiritin, respectively. Additionally, to investigate the separation selectivity, the non-steroidal anti-inflammatory drugs, nucleobases/nucleotides, and alkaloids/glycosides were separated; the HPLC fingerprinting of the Cortex phellodendri extract was also conducted, and the separation performance was superior to that of the C18 column in terms of peak shape, resolution, and analytical time. The results revealed that the prepared SIL-PS possessed multifunctionalities for multiretention and could be promising for complicated samples.     

Liquid chromatographic separation of alkaloids in herbal medicines: Current status and perspectives

Alkaloids are a widespread group of basic compounds in herbal medicines and have attracted great interest due to various pharmaceutical activities and desirable druggability. Their distinctive structures make chromatographic separation fairly difficult. Peak tailing, poor resolution, and inferior column‐to‐column reproducibility are common obstacles to overcome. In order to provide a valuable reference, the methodologies and/or strategies on liquid chromatographic separation of alkaloids in herbal medicines proposed from 2012 to 2019 are thoroughly summarized.     

The chromatographic quantification of hydrophobicity using micellar mobile phases

Summary In micellar liquid chromatography (MLC), the hydrophobicity of a compound is the predominant factor in its retention and interaction with micelles. A non-linear empirical model can describe the dependence between the retention factor (logk) in MLC and the logarithm of partition coefficients octanol-water (logP). An algorithm based on such a model has been used to makelogP predictions. Retention data for series of neutral compounds eluted with different mobile phases and alkyl-bonded stationary phases have been used to test the predictive ability of the algorithm. The results of this approach are compared with those obtained from automatic computational software packages.     

Liquid Chromatograph Detector for Trace Analysis of Non-Volatile N-Nitroso Compounds

Abstract

A Thermal Energy Analyzer has been interfaced to a high performance liquid chromatograph. The hplc-TEA system can be used for analysis of nanogram amounts of N-nitroso compounds.     

烷基酚聚氧乙烯醚在不同液相色谱分离模式中的分离研究

考察了烷基酚聚氧乙烯醚在反相色谱、正相键合色谱、硅胶吸附色谱、体积排阻色谱4种不同液相色谱分离模式中的分离效果,分别采用Kromasil C_(18)(250 mm× 4.6 mm,5 μm)、Agilent ZORBAX NH2(250 mm× 4.6 mm,5 μm)、Waters Spherisorb S3W(150 mm×2.0 mm,3 μm)和Shodex MSpak GF-310 2D(150 mm×2.0 mm,5 μm)色谱柱,以225 nm为紫外检测波长,对不同液相色谱分离模式的流动相组成、梯度洗脱条件、柱温、流速等进行了优化,并对烷基酚聚氧乙烯醚在不同液相色谱分离模式中的保留机理进行了初步探讨.结果表明,正相键合色谱实现了烷基酚聚氧乙烯醚的最佳分离;硅胶吸附色谱和体积排阻色谱的分离效果较正相键合色谱稍差.     

Chromatographic determination of caffeine in pharmaceutical formulations using micellar mobile phases

Summary An HPLC procedure is described for the determination of caffeine in pharmaceutical preparations. A Spherisorb octadecylsilane ODS-2 C₁₈ analytical column and spectrophotometric detection at 273 nm were used. The chromatographic behaviour of caffeine with different micellar eluents containing sodium dodecyl sulphate (SDS) is described. The determination of caffeine in pharmaceutical preparations was performed by use of a mobile phase containing 0.05 M sodium dodecylsulphate (SDS) and 1.5% propanol at pH7. At a 6.0 g mL^–1 concentration level the peak area and peak height repeatability were 2.6 and 2.4%, respectively. The application of the proposed method to the analysis of five pharmaceutical formulations, using peak heights as the dependent variable, gave recoveries between 85 and 104% of the values declared by the manufacturers. The proposed procedure for the determination of caffeine is rapid (15 min per sample), reliable and free from interferences.     

HPLC study of the intramolecular cyclization of a new nematogenic molecule. The gas chromatographic properties of the resulting liquid crystal

Summary The internal cyclization of a new phenyldiazene liquid crystal (called A), with an activated methylene group in theortho position to the diazo linkage, has been studied. The kinetics of cyclization were studied at different temperatures and followed by HPLC. Separations were performed on a 30 cm×0.4 cm silica column withn-heptane-tetrahydrofuran-acetonitrile, 190∶20∶5 (v/v), as mobile phase. The Van't Hoff plot (of ln reaction constantk against 1000/T) gives a mean activation energy of 101.3±2.1 kJ mol⁻¹. The analytical properties of A and the final compound B during the decomposition were investigated by gas chromatography on home-made glass capillary columns coated with A. The retention times of the solutes tested became constant when the B/A ratio reached 5, which corresponds to 83% cyclization. The nematic phase of B has interesting properties enabling the separation of the isomers of decalin, the positional isomers of diethylbenzenes and phenols, and some polyaromatic hydrocarbons and their derivatives.     

Hexadecyltrimethylammonium bromide/ethanol/water systems as mobie phase in reverse phase high performance liquid chromatography. Study of metal-diethyldithiocarbamate complexes retention

Summary This paper presents the, chromatographic retention of Co(II), Ni(II) and Cu(II) as diethyldithiocarbamate complexes in the presence of hexadecyltrimethylammonium bromide/ethanol/water systems, as mobile phase, by reversed phase high performance liquid chromatography. The presence of an organic modifier reduces the retention times and improves the efficiency. In order to evaluate the interaction between the metal complexes and the mixed micellar system the values of solute binding constants are calculated in, two ways: a) Arunyanart and Cline-Love's treatment and b) multiple regression analysis taking account of the ethanol percentages.