解吸附电晕束电离质谱法快速检测中成药及保健食品中非法添加的β-受体阻滞剂

建立了新型的解吸附电晕束离子源耦合离子阱质谱法(DCBI-MS),在无需复杂的样品前处理及色谱分离的条件下,可快速检测降血压中成药及保健食品中非法添加的7种β-受体阻滞剂阿替洛尔、比索洛尔、美托洛尔、普萘洛尔、盐酸塞利洛尔、盐酸贝凡洛尔和卡维地洛.采用一级质谱快速筛选和二级质谱确证的方法对目标化合物进行了定性和半定量测定.各目标物的检出限均低于0.1 mg/L,在0.5～100 mg/L浓度范围内线性关系良好.实验获得的7种β-受体阻滞剂的裂解规律为芳氧丙醇胺类化合物的质谱检测提供了参考依据.通过与高效液相色谱-电喷雾离子化质谱法(HPLC-ESI/MS)对比表明,DCBI-MS方法的检测结果可靠.对9种市售样品进行检测,有1批次中成药检出含有未标示的卡维地洛.结果表明,DCBI-MS法测定单个样品的时间不超过1 min,分析速度快,可以在大批量复杂基质样品中β-受体阻滞剂的筛查和药品品质的在线监测中发挥重要作用.     

High throughput screening of O-glycosylation conditions

We report a novel methodology for rapid and quantitative screening of O-glycosylation reactions of application to the analysis of parallel reaction systems. Our system exploits perdeuterated benzyl (Bn-d₇) ether, and stereoselectivity and yield are evaluated by ¹H NMR and MALDI-TOF MS, respectively. This paper summarizes over 240 screenings of 1 → 3 linkage formation between glucose residues targeting the α-isomer in high yield.     

Rapid resolution liquid chromatography-mass spectrometry and high-performance liquid chromatography-fluorescence detection for metabolism and pharmacokinetic studies of ergosta-4,6,8(14),22-tetraen-3-one

Ergosta-4,6,8(14),22-tetraen-3-one (ergone) from many medicinal plants has been demonstrated to possess a variety of pharmacological activities in vivo and in vitro, including cytotoxic, diuretic and immunosuppressive activity. Metabolism and pharmacokinetic studies on rat were conducted for ergone. Rapid resolution liquid chromatography with atmospheric pressure chemical ionization tandem multi-stage mass spectrometry (RRLC-APCI-MSⁿ) and high-performance liquid chromatography with fluorescence detection (HPLC-FLD) methods were applied for the identification and quantification of ergone and its metabolite from rat plasma, faeces and urine. A metabolite was identified by RRLC-DAD-APCI-MSⁿ: 22,23-epoxy-ergosta-4,6,8(14)-triaen-3-one (epoxyergone). The concentrations of the analyte with its metabolites were determined by HPLC-FLD at excitation wavelength of 370 nm and emission wavelength of 485 nm. The samples were deproteinized with methanol after addition of camptothecin as internal standard (IS). The analysis was performed on a Diamonsil C18 column (150 mm × 4.6 mm × 5 μm) with a mobile phase gradient consisting of methanol and water at a flow rate of 1 mL min⁻¹. The assay was linear over the concentration range of 42-1500, 36-7500 and 42-1500 ng mL⁻¹ for plasma, faecal homogenate and urine respectively. The absolute recoveries were found to be 97.0 ± 1.2%, 98.1 ± 0.7% and 96.6 ± 1.8% for plasma, faecal homogenate and urine respectively. The intra-day and inter-day relative standard deviations (RSD) were less than 10%. The previous HPLC-MS/MS method is not affordable for most laboratories because of the specialty requirement and high equipment cost. However, the HPLC-FLD method is economic and operating simply for quantitative determination of ergone and its metabolite in rat plasma, faeces and urine. In addition, liquid chromatography coupled with ion trap multi-stage mass spectrometry is becoming a useful technique for ergone metabolite identification.     

高质量CdTe量子点的水相快速合成

系统考察了水相合成CdTe量子点的主要影响因素, 通过改变无水乙醇-水体系的体积, 提高NaHTe的合成质量, 并调整反应温度, 改变反应的初始pH值, 在水相中快速合成了量子产率高、粒径分布范围窄的CdTe量子点, 实现了对量子点发光性质的调控, 在最佳条件(无水乙醇3 mL, 水1 mL, 反应初始pH 8.0, 反应温度40 ℃)下, 最高量子产率达68%. 量子点胶体溶液在回流过程中有时产生白色沉淀, 放置7 d后, 未过滤白色沉淀的量子点比过滤后的量子点荧光强度提高15%, 白色沉淀还有减小粒径分布的作用.     

A chemiluminescence biochemical oxygen demand measuring method

A new chemiluminescence biochemical oxygen demand (BOD_CL) determining method was studied by employing redox reaction between quinone and Baker's yeast. The measurement was carried out by utilizing luminol chemiluminescence (CL) reaction catalyzed by ferricyanide with oxidized quinone of menadione, and Saccharomyces cerevisiae using a batch-type luminometer. In this study, dimethyl sulfoxide was used as a solvent for menadione. After optimization of the measuring conditions, the CL response to hydrogen peroxide in the incubation mixture had a linear response between 0.1 and 100 μM H₂O₂ (r² = 0.9999, 8 points, n = 3, average of relative standard deviation; R.S.D._av = 4.22%). Next, a practical relationship between the BOD_CL response and the glucose glutamic acid concentration was obtained over a range of 11-220 mg O₂ L⁻¹ (6 points, n = 3, R.S.D._av 3.71%) with a detection limit of 5.5 mg O₂ L⁻¹ when using a reaction mixture and incubating for only 5 min. Subsequently, the characterization of this method was studied. First, the BOD_CL responses to 16 pure organic substances were examined. Second, the influences of chloride ions, artificial seawater, and heavy metal ions on the BOD_CL response were investigated. Real sample measurements using river water were performed. Finally, BOD_CL responses were obtained for at least 8 days when the S. cerevisiae suspension was stored at 4 °C (response reduction, 69.9%; R.S.D. for 5 testing days, 18.7%). BOD_CL responses after 8 days and 24 days were decreased to 69.9% and 35.8%, respectively, from their original values (R.S.D. for 8 days involving 5 testing days, 18.7%).     

Rapid bonding of Pyrex glass microchips

A newly developed vacuum hot press system has been specially designed for the thermal bonding of glass substrates in the fabrication process of Pyrex glass microchemical chips. This system includes a vacuum chamber equipped with a high-pressure piston cylinder and carbon plate heaters. A temperature of up to 900 degrees C and a force of as much as 9800 N could be applied to the substrates in a vacuum atmosphere. The Pyrex substrates bonded with this system under different temperatures, pressures, and heating times were evaluated by tensile strength tests, by measurements of thickness, and by observations of the cross-sectional shapes of the microchannels. The optimal bonding conditions of the Pyrex glass substrates were 570 degrees C for 10 min under 4.7 N/mm(2) of applied pressure. Whereas more than 16 h is required for thermal bonding with a conventional furnace, the new system could complete the whole bonding processes within just 79 min, including heating and cooling periods. Such improvements should considerably enhance the production rate of Pyrex glass microchemical chips. Whereas flat and dust-free surfaces are required for conventional thermal bonding, especially without long and repeated heating periods, our hot press system could press a fine dust into glass substrates so that even the areas around the dust were bonded. Using this capability, we were able to successfully integrate Pt/Ti thin film electrodes into a Pyrex glass microchip.     

Au@PVP核壳纳米粒子作为表面增强拉曼散射基底检测孔雀石绿

采用水热法合成了粒径均一、壳层厚度可控的Au@PVP核壳纳米粒子,利用壳层PVP分子分散纳米粒子的特性,使其形成均一、排列致密的单层结构,利用其内核金纳米粒子的等离子共振效应实现了孔雀石绿( MG)分子的表面增强拉曼检测。通过优化吸附时间与壳层厚度,在致密的、均匀的核壳纳米粒子表面增强拉曼散射(SERS)基底上实现MG分子高灵敏分析检测,检测线性范围1×10-10~1×10-5 mol/L,线性相关系数R2达到0.98,检出限可达1×10-12 mol/L。将本方法用于罗非鱼鱼肉中MG含量检测,样品未检出,样品加标回收率为70.8％~126.0％。结果表明,本方法快速准确、操作简单,可用于鱼肉中MG的快速检测。     

Mo对脱合金制备的Ni-Mo电极骨架结构与析氢性能的影响

采用快速凝固结合脱合金化方法制备了不同Mo含量的纳米多孔Ni-Mo合金,通过X射线衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）和N₂吸附-脱附分析等对多孔合金的物相、形貌结构及孔径分布进行了表征,并通过线性扫描伏安、Tafel斜率、交流阻抗和循环伏安等方法测试了多孔合金电极的电催化析氢性能.结果显示,多孔合金电极材料在50 mA/cm²电流密度下析氢过电位随着Mo含量的增加先降低后升高,Ni_2.5Mo_2.5合金析氢活性最强,过电位为218 mV,析氢过程由Volmer-Heyrovsky步骤控制,交换电流密度为0.29 mA/cm²,经1000周循环后的极化曲线基本保持原状,50 mA/cm²电流密度下过电位增加3.67%,表现出优良的析氢稳定性.     

硝酸胍的单点滴定法快速分析

报道了以Ｓ－ 十二烷基双硫腙－ 苦味酸为载体制备苦味酸根离子电极, 研究了电极的性能, 并以该电极为指示电极研究了硝酸胍的单点滴定分析, 导出了定量关系式。 以０ ．１００ ０ ｍｏｌ／ Ｌ 标准硝酸胍溶液滴定０ ．１００ ０ ｍｏｌ／Ｌ 苦味酸, 控制滴定至９５ ％ ,１０ 次实验的平均值为０ ．１００ ２ ｍｏｌ／Ｌ, 相对标准偏差为０ ．２４ ％ , 滴定至９０％ ～９５ ％ 相对标准偏差小于０ ．３ ％ 。 用该法进行工业硝酸胍含量分析, 数分钟就能完成, 结果与重量法很好吻合。     

Characterisation of proanthocyanidin aglycones and glycosides from rose hips by high-performance liquid chromatography-mass spectrometry, and their rapid quantification together with vitamin C

Fifteen individual proanthocyanidin aglycones and 19 glycosides, together with a complex mixture of chromatographically non-separated tetra- to octameric proanthocyanidin glycosides were detected--the non-separated glycosides being novel natural products--and characterised from dog rose hips using high-performance liquid chromatography-electrospray ionisation mass spectrometry (HPLC-ESI-MS). Along with these phenolics, a 50% aqueous ethanol extract of rose hips was found to contain high levels of Vitamin C. A simple and rapid HPLC method assisted by diode array detection for the estimation of the total concentration of proanthocyanidin aglycones and glycosides, as well as Vitamin C, in rose hip extracts was developed.