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21.
Herein, we report a template free and surfactant less electrochemical approach for the preparation of flower‐like yttrium hexacyanoferrate (YHCF) particles on reduced graphene oxide (RGO) modified glassy carbon electrode (GCE). The morphology of YHCF particles has been controlled by varying the molar ratio of Y(NO3)2 and K3Fe(CN)6 for the first time. The surface morphology of as‐prepared RGO/YHCF composite was characterized using SEM, EDX, IR and XRD methods. The electrocatalytic activity of the RGO/YHCF composite modified GCE towards Paracetamol (PA) oxidation has been investigated by using cyclic voltammetry (CV) and linear sweep voltammetry (LSV). Besides, the practical feasibility of the fabricated modified GCE has been demonstrated through the determination of PA from commercially purchased Paracetamol tablets.  相似文献   
22.
目的 对马莲花中的微量元素进行分析.方法 采用微波消解法处理样品,利用电感耦合等离子体质谱法(ICP-MS)对马莲花中钾、钠、钙、镁、铜、铁、锌、锰、钼、镍等10种元素进行测定.所测元素校准方程的相关系数均大于0.999 0,回收率范围为90.2% ~107.0%,相对标准偏差为1.54%~7.57%.结果 马莲花中含有丰富的钾、钙、镁等元素.结论 该法简便、快速、准确,灵敏度高,可用于马莲花中10种元素的同时测定.  相似文献   
23.
The novel nanostructures of CuO with improved morphology are strongly required for the development of devices with enhanced performance. In this study flower like nanostructures of CuO are synthesized by hydrothermal method using urea as tuning material for the morphology of CuO during the growth process. Scanning electron microscopy (SEM) and X‐ray diffraction (XRD) techniques were used for the characterization of these nanostructures. The nanostructures are highly dense, uniform and well aligned on the gold coated glass substrate. Moreover, CuO nanostructures exhibited pure phase of CuO. These novel CuO nanostructures were potentially used for the construction of cadmium ion sensor by functionalizing with tetrathia‐12‐crown‐4 a selective cadmium ion ionophore. The proposed cadmium ion sensor has detected the wide range of cadmium ion concentrations from 1.0×10?9–1.0×10?1 M with a sensitivity of 29.3±0.3 mV/decade and also a fast response time of less than 10.0 s is demonstrated. CuO nanostructures based cadmium ion selective electrode has also shown excellent reproducibility, repeatability, selectivity, and stability. The sensor electrode was also used as indicator electrode for the confirmation of practical utility and the obtained result describes the good behavior of the sensor in the potentiometric titration for the determination of cadmium ions.  相似文献   
24.
火焰原子吸收光谱法测定12种药用植物花中金属元素   总被引:1,自引:0,他引:1  
采用浓硝酸-高氯酸(4+1)溶解消化方法进行样品处理,火焰原子吸收光谱法对12种药用植物花中Na、K、Ca、Mg、Zn、Fe、Cu、Mn、Cr、Pb、Ni、Co和Cd13种金属元素分析测定.研究测定不同元素仪器的最佳工作条件、方法的准确性、精密度及介质硝酸浓度对各元素测定结果的影响.结果表明:在实验范围内,硝酸浓度对测定结果无明显影响.12种药用植物花富含人体所需的金属元素Na、K、ca、Mg、Zn、Fe、Cu、Mn.研究发现同一品种不同地区的药用植物花中元素的含量存在一定的差异,同一地区同一品种不同时期采集的药用植物花中元素的含量也存在差异.该方法校准曲线线性关系良好(r=0.9969-1.0000),加标平均回收率在96.2%-109.9%,RSD平均值在0.55%-2.90%,在选定的测定条件下,各元素间相互无干扰,火焰原子吸收光谱法快速、简单,结果可靠.  相似文献   
25.
Narcissus pseudonarcissus (daffodil) is a valuable plant for the cosmetic, pharmaceutical and therapeutical traits. The flower volatile compounds (FVCs) of ten Narcissus pseudonarcissus cultivars were analyzed by Headspace/Solid Phase Micro Extraction-Gas Chromatography Mass Spectrometry (HS/SPME- GC/MS). 69 and 73 FVCs were detected in perianth and corona of the ten cultivars. The compounds are largely comprised of monoterpenes, sesquiterpene, benzenoid compounds and other minor compounds classes. Monoterpenes were major component among the FVCs, with beta-ocimene and beta-myrcene as the two major compounds in most perianths and coronas. The composition and content of the FVCs of different cultivars are quite different from each other.  相似文献   
26.
用水将荞麦花中的水溶性成分提取后,再从水溶性提取物中将黄酮类物质分离,用硝酸铝-亚硝酸钠方法对黄酮的含量进行了测定,求得其校准曲线的回归方程为y=11.902x-0.021,相关系数为r=0.9996,平均回收率为100.8%,RSD=0.98%(n=5)。  相似文献   
27.
采用邻二氮菲-Fe2+氧化法,邻苯三酚自氧化法以及卵黄脂蛋白不饱和脂肪酸(PUFA)过氧化体系,对甘青铁线莲花乙醚提取物、甲醇提取物、乙醇提取物和槲皮素的抗氧化活性进行测定和比较。结果表明,甘青铁线莲花不同溶剂提取物对不同的自由基清除作用差异较大。与槲皮素相比较,各提取物对超氧阴离子自由基(·O2-)清除的强弱为:槲皮素>乙醚提取物>乙醇提取物>甲醇提取物。对于羟基自由基(·OH)的清除能力乙醚提取物优于其他2种提取物,但低于槲皮素,对抑制卵黄脂蛋白脂质过氧化(LPO)作用的大小依次为乙醇提取物>槲皮素>乙醚提取物>甲醇提取物。因此,不同溶剂的提取物均具有一定的抗氧化性,其中乙醚提取物对几种自由基的清除作用相对较好,三种提取物对脂质过氧化物作用抑制最强,可以作为潜在的天然抗氧化剂开发利用。  相似文献   
28.
PanaxquinquefoliumL .belongstothePanaxgenusoftheAraliaceae .ItoriginatesinAmericaandCanada .Itsroots ,afamousandexpensivetraditionalChinesemedicinalmateri al,havebeenstudiedcontinuallysinceitssuccessfulcultivationinChinainthe 1 970’s .Inre centyearsthedevelop…  相似文献   
29.
In this article we present a survey of the pigments found in the flowers and fruits of old and modern varieties of roses. The yellow colors are produced by carotenoids, the reds by anthocyanins, and the modern oranges by a mixture of the two. The great structural diversity of the carotenoids contrasts with a surprisingly small number of anthocyanins. For the carotenoids found in roses, a clear correspondence exists between the structure and the breeding partners used; the old yellow roses, which arose from crosses with Chinese varieties, mainly contain carotenoids from early stages in the biosynthesis, while in the modern yellow roses, which are descended from Central Asian foetida types, hydroxylations, epoxidations, and epoxide transformations readily occur. A recently elucidated carotenoid degradation sequence follows the scheme C40 → C13 + C27 → C13 + C14. The C13 compounds are odoriferous substances that contribute to the scent of roses. In the physiological pH region, copigmentation with flavonol glycosides is crucial for stabilization of the anthocyanin chromophores. Many roses, including the “apothecary's rose”, which was once used medicinally, contain large amounts of strongly astringent ellagitannins, monosaccharide esters of gallic acid.  相似文献   
30.
建立了间接顶空固相微萃取-气相色谱-质谱对红花香雪兰天然花香成分的分析方法。首先利用气体采样装置对花香成分进行固相富集,富集后的花香成分在浸提液中解析,之后利用顶空固相微萃取方法对浸提液中的花香成分进行分析。红花香雪兰花香中主要成分(沉香醇、松油醇、紫罗兰酮和二氢紫罗兰酮)定量分析优化实验条件:Florisil(弗罗里硅土)作为吸附剂,水-甲醇混合液(9∶1, V/V)和0.6 mol/L HCl作为浸提液,萃取温度70℃,平衡时间为25 min。实验结果表明,沉香醇和松油醇在1~100μg/mL范围内有良好的线性关系(R2≥0.981),检出限分别为0.05和0.10μg;二氢紫罗兰酮和紫罗兰酮在0.5~50μg/mL范围内有良好的线性关系(R2≥0.988),检出限为0.02μg。  相似文献   
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