Determination of Trace Elements in Dendrobium Officinale Cultivated in Various Conditions

Dendrobium officinale is an important medicinal plant in traditional Chinese medicine. The consumption of D. officinale has increased rapidly in recent years due to the health awareness among Chinese people. The present study aimed to determine trace elements levels in 42 D. officinale samples and to utilize the elemental data for identifying the cultivation technique. Eighteen trace elements (B, V, Cr, As, Mn, Fe, Mo, Cu, Zn, Se, Sr, Sn, Ti, Al, Co, As Pb, Cd, and Bi) were determined by inductively coupled plasma–mass spectrometry. Of the 11 essential elements, the mean concentrations ranged from 30.6?µg?kg^?1 (Mo) in D. officinale with greenhouse cultivation to 161?mg?kg^?1 (Fe) in D. officinale with rock cultivation, and the contributions of Mn may exceed the dietary reference intake value by the uptake of 20?g of D. officinale. Of the seven toxic elements, the mean concentrations ranged from 3.29?µg?kg^?1 (Bi) in the D. officinale with greenhouse cultivation to 342?mg?kg^?1 (Al) in the D. officinale with rock cultivation, and the contributions of Al may exceed the provisional tolerable daily intake value by the uptake of 20?g of D. officinale. The concentrations of seven metals (Bi, Pb, Fe, Al, Cr, As, and Mo) were utilized to identify the cultivation technique of the analyzed D. officinale samples through linear discriminant analysis.     

Determination of Pyrethroids in Dendrobium officinale by Ultrasound/Microwave-Assisted Solid–Liquid–Solid Dispersive Extraction,Gas Chromatography,and Triple-Quadrupole Mass Spectrometry

An ultrasound/microwave-assisted solid–liquid–solid dispersive extraction method was developed for the determination of 16 pyrethroid insecticides in Dendrobium officinale. The extraction and purification were performed in one step. The pyrethroids were extracted with 8:2 acetone:hexane and purified with a mixture of primary secondary amine, Florisil, C18, and graphitized carbon black. The extraction temperature, extraction time, and ultrasound power were optimized. Trans-cyfluthrin-d₆ was used as the internal standard to improve the accuracy. Under the optimized conditions, the recoveries of the pyrethroids were from 72.2 to 113.9% with the limits of detection between 0.29 and 9.38?µg?kg^?1. The optimized method was successfully used for the determination of pyrethroids in commercial D. officinale samples and may allow monitoring pyrethroids in herbal products.     

Ultrasound/microwave‐assisted solid–liquid–solid dispersive extraction with high‐performance liquid chromatography coupled to tandem mass spectrometry for the determination of neonicotinoid insecticides in Dendrobium officinale

A one‐step ultrasound/microwave‐assisted solid–liquid–solid dispersive extraction procedure was used for the simultaneous determination of eight neonicotinoids (dinotefuran, nitenpyram, thiamethoxam, clothianidin, imidacloprid, acetamiprid, thiacloprid, imidaclothiz) in dried Dendrobium officinale by liquid chromatography combined with electrospray ionization triple quadrupole tandem mass spectrometry in multiple reaction monitoring mode. The samples were quickly extracted by acetonitrile and cleaned up by the mixed dispersing sorbents including primary secondary amine, C₁₈, and carbon‐GCB. Parameters that could influence the ultrasound/microwave‐assisted extraction efficiency such as microwave irradiation power, ultrasound irradiation power, temperature, and solvent were investigated. Recovery studies were performing well (70.4–113.7%) at three examined spiking levels (10, 50, and 100 μg/kg). Meanwhile, the limits of quantification for the neonicotinoids ranged from 0.87 to 1.92 μg/kg. The method showed good linearity in the concentration range of 1–100 μg/L with correlation coefficients >0.99. This quick and useful analytical method could provide a basis for monitoring neonicotinoid insecticide residues in herbs.     

秋水仙素诱导铁皮石斛多倍体研究

用不同质量分数秋水仙素处理铁皮石斛种胚原球茎诱导多倍体,结果表明：1.秋水仙素对种胚原球茎的生长有不同程度的抑制作用,对根系生长的抑制尤为明显.2.由于种胚原球茎完整性好,耐受性强,要获得多倍体则需较高质量分数的秋水仙素或较长的处理时间.3.本实验诱导多倍体有相当一部分是非整倍体,通过流式细胞检测到的变异率高于形态学观察的结果.4.经秋水仙素处理后,有些植株的茎变得粗短,出现茎分叉现象,叶片形状呈锯齿状,变小变厚等变异特征.     

红外光谱结合化学计量学快速预测铁皮石斛中总黄酮含量

评价药用植物质量的主要手段之一是有效成分含量检测，不同采收期对药用植物有效成分含量有明显影响。通过傅里叶变换红外光谱(FTIR)结合化学计量学建立快速预测不同采收期铁皮石斛中总黄酮含量的方法，以期为铁皮石斛质量快速预测评价提供研究基础。采收2014年1至12月的铁皮石斛样品干燥粉碎；以氯化铝显色法测定铁皮石斛中总黄酮含量，分析不同采收时间铁皮石斛总黄酮的累积规律；采集样品红外光谱信息，归属红外吸收峰，拟合红外光谱数据和总黄酮含量数据，结合一阶导数、二阶导数、多元散射校正、标准正态变量、正交信号校正等对数据进行预处理，建立偏最小二乘回归模型预测样品中总黄酮含量。结果显示：(1)样品和标准品芦丁均在270 nm附近有共有吸收峰，实验以270 nm为总黄酮定量波长，标准曲线为y=6.076 5x+0.055 8，相关系数r=0.996 6，线性关系良好；重现性、精密度和稳定性相对标准偏差分别为1.00%，0.37%和0.28%，该方法稳定可靠；(2)总黄酮含量随时间变化趋势为先升高后降低，6月-8月样品含量较高，平均含量大于64.10 mg·g-1；(3)铁皮石斛红外光谱数据与总黄酮含量拟合后进行一阶导数、二阶导数、多元散射校正、标准正态变量、正交信号校正等组合处理，用PLSR模型预测铁皮石斛的总黄酮含量，结果最佳预处理方式为2D+SG5+SNV+OSC-PLSR，训练集和验证集r分别为0.979 0和0.882 4，验证均方根误差(RMSEE)和预测均方根误差(RMSEP)分别为2.438 2和4.169 9，铁皮石斛中总黄酮含量预测值与测量值较接近，表明PLS模型可用于总黄酮含量的快速预测。傅里叶变换红外光谱结合化学计量学能实现铁皮石斛中总黄酮含量准确预测，为铁皮石斛质量评价提供快速、有效的方法。     

铁皮石斛多糖含量的高光谱反演研究

铁皮石斛是我国传统的中草药,多糖含量是衡量其品质优劣的一个重要指标。主要研究铁皮石斛多糖含量与光谱间的关系,旨在寻找铁皮石斛多糖含量的无损检测方法。研究方法:实验材料选自不同处理铁皮石斛组培苗和不同生长阶段的驯化苗。其中36个样本作为建模样本建立模型,11个样本作为检验样本对模型进行检验。分别采用偏最小二乘回归法和因子分析法建立样本光谱与多糖含量间的关系。结果表明:(1)光谱一阶微分与多糖含量的相关性优于光谱反射率,其中对多糖含量较敏感的波段主要集中在可见光区域。(2)偏最小二乘回归法的模型决定系数最高,但其预测能力较差。因子分析法模型具有较好预测能力,基于光谱反射率因子分析模型和基于光谱一阶微分因子分析模型的相对分析误差分别为2.269和2.305。     

优化Rpa电压-电感耦合等离子体质谱法测定铁皮石斛中不同部位的14种金属元素

建立了优化Rpa电压-电感耦合等离子体质谱法测定铁皮石斛中不同部位的Mg、Al、K、Ca、Cr、Mn、Fe、Cu、Zn、Ni、As、Se、Cd和Pb 14种金属元素的方法。样品经微波消解后,采用动态反应池去除样品基体带来的质谱干扰,同时针对部分高含量元素的信号溢出问题,实验优化了Rpa电压,免去了样品的二次稀释。各元素的检出限为0.02~32μg/L,日内精密度(RSD,n=6)和日间精密度(RSD,n=12)分别在0.7%~4.6%和1.5%~5.8%之间;样品的加标回收率为83.9%~112%。采用该方法对柑橘叶标准样品(GBW10020)进行了验证,测定值均在参考值范围内。方法对大棚种植的铁皮石斛的不同部位样品进行了测定,发现重金属含量处于较低水平,其中叶和花的重金属含量要显著高于茎中的含量。