Simultaneous determination of ten flavonoids of crude and wine‐processed Radix Scutellariae aqueous extracts in rat plasma by UPLC‐ESI‐MS/MS and its application to a comparative pharmacokinetic study

Radix Scutellariae (RS) is a herbal medicine with various pharmacological activities to treat inflammation, respiratory and gastrointestinal infections, etc. In this study, a rapid, sensitive and selective UPLC‐ESI‐MS/MS method was developed for simultaneous determination of 10 flavonoids – scutellarin, scutellarein, chrysin, wogonin, baicalein, apigenin, wogonoside, oroxylin A‐7‐O‐glucuronide, oroxylin A and baicalin – from RS aqueous extracts in rat plasma with propyl paraben as internal standard (IS). Chromatographic separation was achieved on a C₁₈ column using gradient elution with the mobile phase consisting of methanol and water (containing 0.1% formic acid) at a flow rate of 0.2 mL/min. The detection was performed in multiple reaction monitoring mode using electrospray ionization in negative mode. The validated method showed good linearity over a wide concentration range (r >0.9935). The intra‐ and interday assay variabilities were <9.5% and <12.4% for all analytes, respectively. The extraction recovery ranged from 71.2 to 89.7% for each analyte and IS. This method was successfully applied to pharmacokinetic comparision after oral administration of crude and wine‐processed RS aqueous extracts. There were significant differences in some pharmacokinetic parameters of most analytes between crude and wine‐processed RS. This suggested that wine‐processing exerted effects absorption of most flavonoids. Copyright © 2014 John Wiley & Sons, Ltd.     

A practical strategy for the characterization of coumarins in Radix Glehniae by liquid chromatography coupled with triple quadrupole-linear ion trap mass spectrometry

The aim of the present study was to develop a practical method for the characterization of coumarins in Radix Glehniae by liquid chromatography–mass spectrometry (LC–MS). First, 10 coumarin standards (including two pairs of isomers) were studied, and mass spectrometry fragmentation patterns and elution time rules for the coumarins were found. Then, an extract of Radix Glehniae was analyzed by the combination of two scan modes, i.e., multiple ion monitoring-information-dependent acquisition-enhanced product ion mode (MIM-IDA-EPI) and precursor scan information-dependent acquisition-enhanced product ion mode (PREC-IDA-EPI) on a hybrid triple quadrupole-linear ion trap mass spectrometer. A total of 41 coumarins were identified on the basis of their mass spectrometry fragmentation patterns. This is the first time that these two scan modes have been combined to characterize chemical constituents in traditional Chinese medicine. This new method allowed the identification of coumarins in Radix Glehniae in trace amounts. The methodology proposed in this study could be valuable for the structural characterization of coumarins from complex natural and synthetic sources.     

Identification and determination of the saikosaponins in Radix bupleuri by accelerated solvent extraction combined with rapid‐resolution LC‐MS

A method based on accelerated solvent extraction combined with rapid‐resolution LC–MS for efficient extraction, rapid separation, online identification and accurate determination of the saikosaponins (SSs) in Radix bupleuri (RB) was developed. The RB samples were extracted by accelerated solvent extraction using 70% aqueous ethanol v/v as solvent, at a temperature of 120°C and pressure of 100 bar, with 10 min of static extraction time and three extraction cycles. Rapid‐resolution LC separation was performed by using a C₁₈ column at gradient elution of water (containing 0.5% formic acid) and acetonitrile, and the major constituents were well separated within 20 min. A TOF‐MS and an IT‐MS were used for online identification of the major constituents, and 27 SSs were identified or tentatively identified. Five major bioactive SSs (SSa, SSc, SSd, 6″‐O‐acetyl‐SSa and 6″‐O‐acetyl‐SSd) with obvious peak areas and good resolution were chosen as benchmark substances, and a triple quadrupole MS operating in multiple‐reaction monitoring mode was used for their quantitative analysis. A total of 16 RB samples from different regions of China were analyzed. The results indicated that the method was rapid, efficient, accurate and suitable for use in the quality control of RB.     

Micellar and aqueous‐organic liquid chromatography using sub‐2 μm packings for fast separation of natural phenolic compounds

The objective of the present work was to investigate the chromatographic behavior of natural phenolic compounds in micellar and aqueous‐organic LC using a short column packed with 1.8 μm particles. Firstly, the effect of ACN and SDS on elution strength and selectivity was examined by isocratic submicellar (0–30% ACN/5% 1‐butanol/1–6 mM SDS) and micellar (0–30% ACN/5% 1‐butanol/40–60 mM SDS) systems. The varied concentrations of two modifiers in the mobile phases revealed different eluting power. Then, the application of organic modifier gradient was discussed in both submicellar and micellar LC using mobile phases of 4 mM SDS/5% 1‐butanol or 50 mM SDS/5% 1‐butanol containing ACN gradient from 0 to 30%, respectively. For micellar system, the separation was found to be better in gradient than isocratic elution. Additionally, the sensitivity of aqueous‐organic LC was examined. The mobile phase was a mixture of ACN and water employing gradient elution at a flow rate of 0.5 mL/min, with analysis time below 9 min. It was found that separation efficiency was significantly better compared with micellar LC. Besides, the aqueous‐organic LC has been applied to separation of various phenolic compounds in Yangwei granule or Radix Astragali samples.     

测定天然和栽培缬草根金属元素的微波和干灰化消解-FAAS法

采用微波消化法和马弗炉干灰法处理天然和栽培缬草根样品，火焰原子吸收光谱法连续测定样品中金属元素，分别检出12种和11种元素，其中Zn、Cu、Fe、Co、Mn、Ni、Cr为生命必需微量元素；两种样品各用两种消化法处理，测得金属元素及含量有差异，干灰法操作简单，但消化温度高、时间长、易挥发、元素容易损失，使检测值偏低；而微波消化法简便、省时、损失减少；两种消化法的加标回收率分别为95％-100％和96％-105％。     

Nonaqueous capillary electrophoresis for rapid and sensitive determination of fangchinoline and tetrandrine in radix Stephaniae tetrandrae and its medicinal preparations

A simple, rapid, and sensitive non-aqueous capillary electrophoresis procedure with head-column field-amplified sample stacking concentration for the analysis of fangchinoline and tetrandrine is established. Optimum separation and stacking conditions were obtained when the sample was injected at 8 kV for 50 s after preliminary pressure injection of ethanol (16.9 kPa) for 0.6 s and separated with the buffer containing 50 mM ammonium acetate, 0.5% (v/v) acetic acid, and 50% (v/v) acetonitrile in methanol medium at 24 kV applied voltage. The analytes were detected by UV at 214 nm. The two bisbenzylisoquinoline alkaloids can be separated within 6 min and quantified with high sensitivity. The detection limits were 0.30 ng mL(-1) for fangchinoline and 0.34 ng mL(-1) for tetrandrine, which indicated that the sensitivities were at least 1000-fold enhanced over those reported in the literature as obtained by UV detection. The method was applied to the analysis of fangchinoline and tetrandrine in Radix Stephaniae tetrandrae and its medicinal preparations with good results.     

解答连续统猜想

连续统猜想，即可数基数后面紧接着就是实数基数，是一个l00多年来未被证明解答的问题．本文首先对无限的根本性进行了证明，然后通过分析论证推翻了集合论中的S＜P（S）（S为无限集合)和R＝2^ω0，并从无限集合的“全体等于部分”这一根本特性出发，证明4个无限基数定理，最后对连续统问题进行了证明解答．     

RP-HPLC法测定木香与川木香中木香烃内酯的含量

目的:测定木香与川木香中木香烃内酯的含量.方法:采用RP-HPLC法,用kromasil色谱柱(250mm×4.6mm,5μm),以甲醇-水梯度洗脱,流速1ml·min-1,柱温30℃,检测波长225nm.结果:在0.4～1.4μg之间,峰面积与进样量的线性关系为A=671028.2864C-65332.7036(r=0.9999),平均回收率为97.3%.结论:所建方法简便、准确、重复性好,可用于木香与川木香中木香烃内酯的含量测定.     

贵州产三颗针药材HPLC指纹图谱的研究

建立贵州产三颗针药材的HPLC指纹图谱.采用高效液相色谱法,色谱条件为:色谱柱:DiamonsilTM(钻石)C18(250 mm×Φ4.6 mm,5μm),乙腈-水(每100 mL中含0.34%磷酸二氢钾)为流动相,梯度洗脱,体积流量1.0 mL/min,检测波长为220 nm,柱温为25℃.该指纹图谱方法重现性较好,可作为贵州产三颗针的一项质控指标.