Pharmacokinetics and tissue distribution study of bisabolangelone from Angelicae Pubescentis Radix in rat using LC–MS/MS

A sensitive and accurate LC–MS/MS method was established for quantifying bisabolangelone in rat plasma and tissues. Bisabolangelone was isolated and purified from Angelicae Pubescentis Radix. The pharmacokinetic and tissue distribution of bisabolangelone after administration to rat was performed by LC–MS/MS. Separation was carried out on a C₈ (4.6 × 100 mm, 1.8 μm) column. The MS/MS transitions of bisabolangelone and tussilagone (internal standard) were set at m/z 249.1 → 109.1 and m/z 391.4 → 217.4, respectively. The lower limit of quantification in plasma and other tissues ranged from 1 to 4 ng/mL. The biosamples were prepared using protein precipitation method with acetonitrile. The recovery was >92%. The results showed that values of maximum concentrations and area under the curve depended linearly on the studied doses (2.5, 5 and 7.5 mg/kg body weight). The other ingredients in Angelicae Pubescentis Radix extract possibly reduce the absorption of bisabolangelone in rat. Tissue distribution revealed that bisabolangelone was widely distributed in vivo. The highest and lowest concentrations of bisabolangelone were found in the stomach and in the brain, respectively. It was concluded that the newly established HPLC–MS/MS method was suitable to describe the pharmacokinetic characteristics of bisabolangelone in rat after administration.     

Fast determination of curcumol, curdione and germacrone in three species of Curcuma rhizomes by microwave-assisted extraction followed by headspace solid-phase microextraction and gas chromatography-mass spectrometry

Curcumol, germacrone and curdione are the main active ingredients in a common traditional Chinese medicine (TCM) of Rhizoma Curcuma, and commonly used as the TCM quality control markers. In the present work, microwave-assisted extraction (MAE) followed by headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) was developed for the quantitative analysis of curcumol, curdione and germacrone in Rhizoma Curcuma. The MAE and HS-SPME parameters were studied, and the method was validated. The optimal MAE conditions obtained were: microwave power of 700 W and irradiation time of 4 min, and HS-SPME optimal conditions were: fiber coating of 100 microm PDMS, extraction temperature of 80 degrees C, extraction time of 20 min, stirring rate of 1,100 rpm, and salt concentration of 30% NaCl. The proposed method provided good precision (RSD less than 12%) and recoveries between 86% and 93%. The proposed method was applied to the determination of the three marker compounds in three species of Curcuma rhizomes (Curcuma wenyujin, Curcuma phaeocaulis, and Curcuma kwangsiensis). To demonstrate the proposed method reliability, a conventional technique of steam distillation was also used for the analysis of curcumol, germacrone and curdione in the TCMs. The results show that MAE-HS-SPME is a simple, rapid, solvent-free and reliable method for the determination of curdione, curcumol and germacrone in TCM, and also a potential and powerful tool for quality assessment of Rhizoma Curcuma.     

Development of microwave-assisted extraction followed by headspace single-drop microextraction for fast determination of paeonol in traditional Chinese medicines

Paeonol is an important active component present in traditional Chinese medicines (TCMs), which was used for the treatment of many diseases such as eczema. In this work, microwave-assisted extraction (MAE) was firstly combined with headspace single-drop microextraction (HS-SDME), and applied to rapid determination of paeonol in two TCMs of Cynanchum paniculatum and Paeonia suffruticosa. In the proposed method, paeonol in TCMs was isolated by using MAE, followed by extraction and concentration by HS-SDME, and detected by gas chromatography-mass spectrometry (GC-MS). The experiment parameters of MAE and HS-SDME were discussed, and the method precision, recovery and detection limit were also studied. To further demonstrate the reliability of the quantification, both the proposed method and a standard method of steam distillation (SD) were simultaneously applied to quantitative analysis of paeonol in TCM samples from different growing areas. The experimental results show that MAE-HS-SDME is a simple and rapid method for the quantitative analysis of paeonol in TCMs, and is also a potential and alternative tool for quality monitoring for the two TCMs of C. paniculatum and P. suffruticosa.     

Analysis of nuclear proteome in C57 mouse liver tissue by a nano-flow 2-D-LC-ESI-MS/MS approach

The analysis of whole cell or tissue extracts is too complex for current protein identification technology and not suitable for the study of proteins with low copy levels. To concentrate and enrich low abundance proteins, organelle proteomics is a promising strategy. This approach can not only reduce the protein sample complexity but also provide information about protein location in cells, organs, or tissues under analysis. Nano-flow two-dimensional strong-cation exchange chromatography (SCX)-RPLC-ESI-MS/MS is an ideal platform for analyzing organelle extracts because of its advantages of sample non-bias, low amounts of sample required, powerful separation capability, and high detection sensitivity. In this study, we apply nano-scale multidimensional protein identification technology to the analysis of C57 mouse liver nuclear proteins. Organelle isolation has been optimized to obtain highly pure nuclei. Evaluation of nucleus integrity and purity has been performed to demonstrate the effectiveness of the optimized isolation procedure. The extracted nuclear proteins were identified by five independent nano-flow on-line SCX-RPLC-ESI-MS/MS analyses to improve the proteome coverage. Finally, a total of 462 proteins were identified. Corresponding analyses of protein molecular mass and pI distribution and biological function categorization have been undertaken to further validate our identification strategy.     

Indirect laser-induced fluorescence detection of diuretics separated by capillary electrophoresis

Indirect LIF detection was applied to the detection of four acidic diuretics separated by CZE. Semiconductor laser was employed to provide the stable excitation of 473 nm. With an optimized electrophoretic buffer system which contained 5 mM of triethylamine, 0.1 microM of fluorescein, and 5% of n-butanol, fast separation of four diuretics (ethacrynic acid, chlorthalidone, bendroflumethiazide, and bumetanide) can be performed within 3 min with the detection limits of 0.2-2 microg/mL. The impacts of buffer components including the concentrations of the electrolytes, fluorescence probe, and the organic additives were demonstrated. The method was applied for the detection of diuretics in urine. As an alternative way for the fast analysis of diuretics, this indirect detection method provided the technical support for future microchip performances, in which diuretics may be detected in the microchip by the common LIF detector without derivatization.     

Preparation of the capillary-based microchips for solid phase extraction by using the monolithic frits prepared by UV-initiated polymerization.

A microfluidic solid phase extraction (SPE) array for sample enrichment was prepared by a simple method, a hot embossing technique. Five fused-silica capillaries (250 microm i.d., 380 microm o.d.) were partly embedded parallel in a polymethyl methacrylate (PMMA) microchip to serve as the extraction channels. Within each of the channels, a 2-mm-long monolithic porous polymer was prepared by in-situ photoinitiated polymerization. This then acted as the frit for packing of the extraction materials (octadecylsilica beads, ODS). By defining the light-exposure window on the channels, one can easily control the length and location of the polymer frits and the ODS beads can be packed at the desired location. With this method, solid phase extraction channels for microfluidic use can be easily prepared without complex fabrication of microstructures. Several SPE channels can be conveniently made in one microchip since the frits can be prepared in different channels through one polymerization; packing of the different channels can also be performed simultaneously. With the use of dilute ephedrine solutions, the sample loading capacity, linearity, and reproducibility were characterized. Coupled with the fast capillary electrophoresis separation, this microchip SPE array was applied for the detection of ephedrines in human urine.     

高功率二极管激光器寿命测试

 介绍了高功率激光二极管不同模式的失效机理，分析了激光二极管不同的寿命测试方法；在冷却水温20℃和实际工作温度下分别对封装的激光器进行了寿命测试。根据试验结果得出退化率，推算出准连续二极管激光器在水温20℃，电流90A，占空比为10%（500Hz，200μs）时，平均激光工作寿命为2.19×10⁹次脉冲；冷却水温35℃时，其平均激光工作寿命下降为1.65×10⁹次脉冲。由实验结果分析得出，高功率激光器封装工艺中的焊料沉积和多层焊接技术，以及工作环境温度是影响激光器可靠性和寿命的关键因素。     

光学速调管改造后辐射段磁场垫补和测量

 合肥国家同步辐射实验室正在开展储存环相干谐波自由电子激光研究，并对原来的光学速调管进行了改造。磁场的垫补和测量方法由原来的整体测量改为分段进行，垫补的使用使各段积分场及位相误差都尽可能小。详述了合肥储存环的光学速调管辐射段磁场垫补的三种方式，测量了垫补前后不同间隙下积分场分布、位相误差及横向均匀度，各项指标都达到了要求。同样的方法将用于色散段和调制段磁场垫补与测量中，为相干谐波自由电子激光研究提供实验保障。