侧柏叶中微量元素的测定

侧柏分布于全国大部分地区,且有很高的药用价值及其他作用,像抗氧化等．本文采用干法和湿法对侧柏叶进行处理,用空气一乙炔火焰原子吸收法测定了其中9种金属元素Fe,Mg,Ca,Zn,Cu,Pb,Ni,Cd,Cr的含量．实验结果表明：侧柏叶中有益元素含量较高,有害元素含量较低,因而具有广阔的发展前景．     

香椿叶水溶性多糖初步纯化及清除自由基活性研究

对香椿叶粗多糖进行了提取,测定了其蛋白质含量,并对其进行了初步纯化,然后对粗多糖和初步纯化多糖进行了抗氧化实验,测定了不同质量浓度的香椿粗多糖和初步纯化多糖对自由基的清除作用．纸层析、GC分析结果表明：香椿叶初步纯化多糖的单糖组成为Xyl,Ara,Rha,Gal,Glc,Gal—A,Man;摩尔比为1．0：3．7：1．3：9．0：2．7：10．0：0．7．抗氧化实验结果表明：不同质量浓度的粗多糖和初步纯化多糖都能有效地清除羟自由基和超氧阴离子,而且初步纯化多糖比粗多糖的清除效率要高,香椿粗多糖对R·有清除作用,而初步纯化多糖在实验规定的浓度范围内对R·却没有清除作用．     

反相高效液相色谱法测定白肋烟烟叶中的游离氨基酸

建立了一种用于烟草中游离氨基酸测定的反相高效液相色谱法．实验采用超声波水解、邻苯二甲醛／3-巯基丙酸作为衍生剂进行柱前衍生．色谱柱为依利特C18柱（4．6mmi．d．×250mm,5μm）,流动相A为18mmol／L的醋酸钠溶液（pH7．2）含体积分数为0．002％的三乙胺和0．3％的四氢呋喃,流动相B组成为：100mmol／L的醋酸钠溶液（pH7．2）-乙腈-甲醇（体积比为1：2：2）,流速为1．0mL／min,柱温为40℃．荧光检测器,激发波长350nm,发射波长450nm．方法的回收率为95．3％～100．7％,RSD为2．32％～9．24％（n=6）．该方法简便、准确、重现性好．测定了不同肥料配比生产的白肋烟烟叶中17种游离氨基酸的含量．结果表明,不论有机肥与无机肥怎样配比,天冬氨酸的含量与各氨基酸相比都是最高的;随着饼肥的加入,大部分氨基酸的含量是先增加后逐渐降低的趋势,15％饼肥＋85％无机肥与30％饼肥＋70％无机肥配比时,大部分游离氨基酸的含量接近,30％饼肥＋70％无机肥配比时的游离氨基酸总量最高,综合考虑,30％饼肥＋70％无机肥配比时的烟叶质量最好．     

锶胁迫条件下生菜光谱效应特征

锶（Sr）胁迫条件下生菜的反射光谱特征会发生明显改变。通过室内生菜水培试验，获取了36个不同生长期、6个不同锶浓度胁迫的生菜叶片400～950 nm波段区间的生化参数信息（叶绿素含量、细胞结构、叶片金属含量）和反射光谱信息，利用光谱技术并结合数学统计方法研究了生菜叶片7个光谱特征参数与实测叶片锶元素含量之间的相关性，优选了较敏感光谱特征参数，建立了其与生菜叶片锶含量的线性回归模型。结果表明，锶胁迫生菜叶片叶绿素含量呈先上升后下降的规律，细胞结构差异不明显。锶胁迫生菜叶片反射光谱直观上无规律，通过采用光谱技术方法分析得出锶胁迫生菜叶片的红边波段位置先“红移”再“蓝移”，红谷波段位置则“红移”，植被指数B4/B3比值先升高后降低，红边归一化植被指数（NDVI）值随着锶浓度的升高而降低。相关性及线性回归模型分析表明红边波段位置与叶片锶含量显著相关。本文为下一步基于光谱特征的叶片重金属含量反演模型的构建提供了较好的数据源和基础理论。     

Simultaneous determination and pharmacokinetics study of three triterpenoid saponins in rat plasma by ultra-high-performance liquid chromatography tandem mass-spectrometry after oral administration of Astragalus Membranaceus leaf extract

A selective and sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of three triterpenoid saponins isolated from Astragalus membranaceus leaf extract. In this article, a method for simultaneous determination of Huangqiyenin A, Huangqiyenin E, and Huangqiyenin K was established for the first time. The method was successfully applied to the pharmacokinetic study of Astragalus membranaceus leaf extract after oral administration. Liquid–liquid extraction was applied to plasma sample preparation. Multiple reaction monitoring mode with an electrospray ion source in positive electrospray ionization was chosen to quantify the analytes. Chromatographic separation was performed on a Waters HSS T3 column, using gradient elution with a mobile phase composed of acetonitrile and 5 mM ammonium acetate/water. The pharmacokinetic results showed that all three compounds had the characteristics of rapid absorption-slow metabolism trend. The time of maximum plasma concentration of Huangqiyenin A is higher than Huangqiyenin E and Huangqiyenin K. And the maximum plasma concentration of Huangqiyenin A is higher as well. The pharmacokinetic results revealed the pharmacokinetic characteristics of the three analytes in rat plasma, which could provide a helpful reference for the further study of Astragalus membranaceus leaf extract.     

Mulberry Leaves (Morus Rubra)-Derived Blue-Emissive Carbon Dots Fed to Silkworms to Produce Augmented Silk Applicable for the Ratiometric Detection of Dopamine

Silk fibers (SF) reeled from silkworms are constituted by natural proteins, and their characteristic structural features render them applicable as materials for textiles and packaging. Modification of SF with functional materials can facilitate their applications in additional areas. In this work, the preparation of functional SF embedded with carbon dots (CD) is reported through the direct feeding of a CD-modified diet to silkworms. Fluorescent and mechanically robust SF are obtained from silkworms (Bombyx mori) that are fed on CDs synthesized from the Morus rubra variant of mulberry leaves (MB-CDs). MB-CDs are introduced to silkworms from the third instar by spraying them on the silkworm feed, the mulberry leaves. MB-CDs are synthesized hydrothermally without adding surface passivating agents and are observed to have a quantum yield of 22%. With sizes of ≈4 nm, MB-CDs exhibited blue fluorescence, and they can be used as efficient fluorophores to detect Dopamine (DA) up to the limit of 4.39 nM. The nanostructures and physical characteristics of SF weren't altered when the SF are infused with MB-CDs. Also, a novel DA sensing application based on fluorescence with the MB-CD incorporated SF is demonstrated.