Liquid chromatography-tandem mass spectrometry method for identification and quantification of two biologically active polyisoprenylated benzophenones, isoxanthochymol and camboginol, in Garcinia species

A sensitive liquid chromatography/electrospray ionization tandem mass spectrometrical (LC/ESI-MS/MS) method was developed for simultaneous identification and quantification of two polyisoprenylated benzophenones, isoxanthochymol and camboginol, in the extracts of the fruit rinds, stem bark, seed and leaves of Garcinia indica and in the fruit rinds of Garcinia cambogia. The separation of isoxanthochymol and camboginol was achieved on an RP-8 column using the solvent system consisting of a mixture of acetonitrile-water (80:20) and methanol-acetic acid (99.0:1.0) as a mobile phase in a gradient elution mode. A multiple reaction monitoring (MRM) method was developed for quantification of isoxanthochymol and camboginol in the above extracts of Garcinia species. Based on a signal-to-noise ratio of 3, the limits of detection in MRM mode for isoxanthochymol and camboginol were 2.0 and 5.0 ng/mL respectively. The method was validated in terms of linearity, accuracy and precision for 6 days. The method developed was found to be useful for identification and quantification of isoxanthochymol and camboginol in the extracts of the fruit rinds, stem bark, seed and leaves of Garcinia indica and in the fruit rinds of Garcinia cambogia.     

气相色谱-串联质谱法测定不同产地大米中的角鲨烯

通过比较大米中角鲨烯的不同提取方法,选用优化后的索氏提取/气相色谱-串联质谱(GC- MS/MS)法对不同产地大米中的角鲨烯进行定性及定量分析.结果表明,该方法在1-50 mg/L质量浓度范围内线性良好,相关系数为0.9987;检出限为0.1 mg/kg;在5,20 mg/kg 2个加标水平下的回收率可达96%-104...     

有机废弃物发酵加富大棚CO2对叶菜类蔬菜生长的影响

采用由作物秸秆与畜禽粪便发酵产生CO2的简易发酵装置来加富大棚CO2,一次堆料可使大棚CO2体积分数维持600 ×10-6 13 d以上,并且可使大棚内的生菜、青菜和油麦菜等叶菜类蔬菜叶片加厚,单株鲜质量分别增加135%、322%和140%,产量分别提高127.1%、122.8%和97.9%.说明农业有机废弃物发酵加富...     

肉苁蓉醇提物的傅里叶变换红外光谱三级鉴定

采用傅里叶变换红外光谱结合二阶导数谱和二维相关红外光谱的三级鉴定技术对肉苁蓉的不同浓度醇提物药液和相应的药渣由表及里地进行了分析与评价研究.结果表明,用乙醇提取肉苁蓉活性成分的加工过程使苯乙醇苷类等活性物质在红外光谱上得以明显体现,并发现70％乙醇提取物中苯乙醇苷类等物质均高于其他浓度提取物.该技术从整体上揭示了乙醇萃...     

HG-AFS法测定铀钼矿钼反萃取液、净化液中砷含量

建立氢化物发生-原子荧光光谱法(HG-AFS)测定铀钼矿钼反萃取液、净化液中砷含量的分析方法。仪器主要工作条件:负高压280 V,灯电流60 mA,原子化器高度9 mm,载气流量400 mL/min,屏蔽气流量1000 mL/min。砷的质量浓度在0～40μg/L范围内与荧光强度呈良好的线性,线性相关系数r=0.9998。方法测定砷的检出限为0.037μg/L,测定结果的相对标准偏差小于5%(n=6),加标回收率为90.5%～102.5%。针对溶液中的钼同多酸和杂多酸以及存在的其它氧化物,采取抗坏血酸-硫脲混合溶液进行预还原,溶液中铀含量约为0.1 g/L时,对砷的测定无影响。该法能满足铀钼矿钼反萃取液、净化液中砷含量0.005～4 g/L的测定要求。     

高光谱图像信息的柑橘叶片光合色素含量分析技术研究

暗箱环境下采集柑橘叶片高光谱图像,采用阈值法提取整叶有效光谱信息区域的平均光谱,比对分析了柑橘叶片光谱信息不同预处理方法和光谱PLS、BPNN和LS-SVM预测模型对叶绿素a、叶绿素b和类胡萝卜素等光合色素含量的预测精度。结果显示,采用MSC对原始光谱进行预处理和LS-SVM建模对叶绿素a含量的预测效果较好,Rp达0.898 3,RMSEP为0.140 4;采用SNV光谱预处理和LS-SVM模型对叶绿素b含量的预测其Rp为0.912 3,RMSEP为0.042 6;采用MAS预处理和PLS模型对于类胡萝卜素含量预测的Rp和RMSEP分别为0.712 8和0.062 4。结果表明:采用高光谱图像信息可较好地进行柑橘叶片叶绿素a,叶绿素b和类胡萝卜素等光合色素含量的预测,为进一步研究柑橘叶片光合色素含量与组分构成的非损伤实时检测提供了依据。     

生物合成纳米金与MWCNTs/L-Cys复合修饰玻碳电极测定左旋多巴

利用荷叶萃取液生物合成纳米金,并与多壁碳纳米管/L-半胱氨酸复合成修饰电极材料,研究了左旋多巴在该修饰电极上的电化学行为.在0.2 mol/L乙酸-乙酸钠体系(pH=2.6)中,氧化峰电流与左旋多巴浓度在0.6~40μmol/L及60~120μmol/L范围内呈良好的线性关系,检出限达5.2×10-8mol/L.实验结果表明,生物合成纳米金复合多壁碳纳米管/L-半胱氨酸修饰电极具有良好的稳定性和高灵敏度,对实际样品测定的回收率在91.2%~102.5%之间.     

Strongly Veined Carbon Nanoleaves as a Highly Efficient Metal‐Free Electrocatalyst

Effective integration of one‐dimensional carbon nanofibers (CNF) and two‐dimensional carbon sheets into three‐dimensional (3D) conductive frameworks is essential for their practical applications as electrode materials. Herein, a novel “vein‐leaf”‐type 3D complex of carbon nanofibers with nitrogen‐doped graphene (NG) was prepared through a simple thermal condensation of urea and bacterial cellulose. During the formation of the 3D complex CNF@NG, the graphene species was tethered to CNF via carbon–carbon bonds. Such an interconnected 3D network facilitates both the electron transfer and mass diffusion for electrochemical reactions.     

Process design based on physicochemical properties for the example of obtaining valuable products from plant-based extracts

Herbal ingredients for use in the food, cosmetic and pharmaceutical industry are mainly gained from plant extracts. The challenge of producing these ingredients is the economic optimization of the design for the corresponding technical processes. To achieve this goal, a systematic, model-based approach is necessary, which is not yet available for complex mixtures (Bart and Pilz, 2010 [11]). The general basis for modeling and simulation of industrial processes is the knowledge of the physical properties of the system. A cost-effective option to get hold of separation factors of mixtures is the direct characterization of the multicomponent system, which has been the subject of earlier publications (Josch et al., 2012 [2]; Josch and Strube, 2012 [3]; Bart and Pilz, 2010 [11]). In this work, a systematic approach is illustrated on how to effectively characterize complex mixtures for a first process design. In addition, physical properties for individual plant components can be determined for modeling to optimize industrial processes. For this purpose, those processes which are well established in the chemical industry, including the use of substance databases and calculation of properties by means of thermodynamic theories, will be discussed. In addition, limitations of these approaches and resulting research requirements are shown.     

The Preparation of Dye Sensitized Solar Cell (DSSC) from TiO2 and Tamarillo Extract

Energy crisis is what being faced by every country today. Many efforts have been devoted to overcome the problems. One of several offered solutions is to develop solar cells (SCs) since solar energy is abundant and free to use. Especially in a tropical country like Indonesia, solar energy is available a whole year with quite high power 450 mWcm^-2. Several types of SCs, especially silicon-based, have been mass-produced and applied in our daily life. Silicon-based SC has high efficiency yet has high price. Dye Sensitized Solar Cell is an inexpensive type of SC. The natural ingredients could be utilized as dyes for DSSC. In this research, tamarillo extract was employed as the dye for TiO₂-based DSSC. TiO₂ powder was spin-coated on top of Fluorine- Doped Tin Oxide (FTO) conductive glass and calcined at 550 ̊C, 650 ̊C and 750 ̊C each for 60 and 120 min. Scanning ElectronMicroscope (SEM) and X-Ray Diffractometer (XRD) were used to characterize the morphology and structure of the material. Brunauer-Emmet-Teller (BET) analysis was utilized to measure the material active surface area. As the result, the sample calcined at 650 ̊C for 60 minutes showed the highest electrical performance of 542.5 mV and 0.356 mAcm^-2 which corresponded to an SC efficiency of 0.043%. This result was supported by the BET analysis showing the sample calcined at 650 ̊C for 60 min had the largest active surface area of 9.3 m²g^-1. A large active surface area enabled more dye and electrolyte to be stored inside the material so that photon adsorptions from solar energy became more effective and resulting in higher efficiency. Despite of the small efficiency, this work demonstrated the opportunities of tamarillo and TiO₂ to be applied as a DSSC.