紫外光分光光度法测定食品包装纸用天然色素虎杖黄酮含量的研究

研究了紫外光分光光度法测定食品包装纸用色素虎杖黄酮含量的方法,以芦丁为参照品,测量波长为359nm,平均回收率为99.96%,精密度为1.34%,说明紫外分光光度法是一种较理想的测定方法.     

紫外光分光光度法测定食品包装纸用黄柏黄酮含量的研究

研究了紫外光分光光度法测定食品包装纸用色素黄柏黄酮含量的方法,以芦丁为参照品,测量波长为359 nm,平均回收率为99.90%,精密度为1.27%,说明紫外分光光度法是一种较理想的测定方法.     

基于紫外可见分光光度法的富勒烯纯度测量不确定度评定北大核心CSCD

富勒烯纯度影响了其力学、热学等性能及其在润滑、超导等领域的应用。紫外可见分光光度法仪器简单、操作简便,适用于富勒烯纯度的快速测量。然而,目前紫外可见分光光度法对富勒烯纯度测量的相关文献中,尚未有对测量影响因素的系统分析。因此,基于紫外可见分光光度法,建立了C 60富勒烯纯度测量的数学模型,通过分析紫外可见分光光度法测量富勒烯纯度的不确定度来源,进行不确定度评定。结果表明:电弧法合成的C 60富勒烯纯度为(74±7)%,k=2;燃烧法合成的C 60富勒烯纯度为(99±9)%,k=2。同时,通过不确定度评定,分析最大不确定度分量主要来源于标准曲线的拟合和标准系列溶液的配制,为后续基于紫外可见分光光度法的富勒烯纯度测量降低不确定度、提高测量准确性提供了技术依据。     

分光光度法测定食品包装纸用紫甘薯总黄酮的含量

以芦丁为标准样品,比较了可见光及紫外光分光光度法测定食品包装纸用色素紫甘薯总黄酮的方法.在可见光分光光度法中,以硝酸铝作显色剂,测量波长为520nm.而在紫外分光光度法,测量波长为370nm.结果表明,紫外分光光度法是一种较理想的测定紫甘薯总黄酮方法.     

矿石中微量铀的分析

用分光光度法和中子活化分析法测定了同一铀矿石不同粒度的样品中铀的含量,并对两种方法的结果进行了比较.对四组不同粒度的样品的分析结果显示,分光光度法的结果略高于中子活化分析的结果.两种方法结果都表明,单位质量的矿石中铀的含量随粒度减小而增加.用中子活化分析u的不确定度小于1%;分光光度法的相对标准偏差优于8%,在误差范围内与活化分析的结果保持一致,其值略高于活化分析的结果.     

鱼腥草中铁含量分析方法研究

本文采用X-射线荧光光谱法对鱼腥草中共存元素进行了普查,通过一系列的干扰因素试验及分析,发现经典的邻二氮菲分光光度法可直接用于鱼腥草中铁含量的测定,且共存元素不产生干扰。将邻二氮菲分光光度法用于鱼腥草中铁含量的测定,方法精密度(RSD)为1.8%～2.7%,平均回收率为92.0%,鱼腥草样品中铁含量为129.3μg/g。该方法简便、准确,为合理食用鱼腥草进行补铁提供了可供参考的分析方法。     

紫外分光光度法测定替硝唑注射液中替硝唑的含量的研究

目的：建立紫外分光光度法测定替硝唑注射液中替硝唑的含量。方法：紫外分光光度法，检测波长为317nm。     

桉叶精油微胶囊包埋油含量测定方法的比较

目的比较3种测定桉叶精油微胶囊包埋油含量的方法,为包埋油含量的测定提供科学依据。方法采用干燥失重法、挥发油测定法和紫外分光光度法对桉叶精油微胶囊包埋油含量进行测定,并对这3种方法进行对比分析。结果 3种方法的RSD值均不超过5%,加标回收率均在90%~120%之间,均具有良好的精密度和准确度。干燥失重法测定结果偏高。紫外分光光度法操作复杂,相对成本较高,但检测速度快。挥发油测定法操作简便、成本低,但耗时较长。结论 3种方法均适合包埋油含量的测定,但挥发油测定法和紫外分光光度法精密度和准确度更高。     

分光光度法测定蔬菜中的碳水化合物

利用分光光度法具有的简便、快速等优点,测定了7种蔬菜中的碳水化合物含量,加标回收率在98.7%～101.4%,相对标准偏差(RSD)为1.81%,具有较高的准确度。     

脲铵氮肥中缩二脲测定方法的研究

HG/T 4214-2011《脲铵氮肥》中规定,测定脲铵氮肥中缩二脲含量的依据为GB/T 22924—2008《复混肥料(复合肥料)中缩二脲含量的测定》。本文对分光光度法和高效液相色谱法两种方法进行比较。试验结果为分光光度法由于其他离子干扰太多,检测结果偏高;用液相色谱法测定快捷干扰小,加标回收率达到98.2%~101.5%,检测方法更准确可靠。     

刚果红水杨酸法测定水中的微量镁

建立一种简便快速的水中微量镁的测定新方法。利用镁离子与刚果红、水杨酸反应,在0.08mol/L的NaOH溶液的条件下显色,进行分光光度分析。在实验最适条件下,镁离子含量在0.01μg-2μg/ml之间时,镁离子含量与吸光度线性关系良好,方法检出限为0.08μg/ml相对标准偏差4.3%,样品加标回收率在96%~106%。本方法操作简便,灵敏度高。用于水中微量镁的测定,结果满意。     

银杏叶中黄酮的水提取及HPLC测定

本文运用水提法提取了银杏叶中的黄酮,提取物经酸水解后,用HPLC—UV法进行定量分析,测得黄酮用本法提取的产量为1.78%(W/W)。     

茶叶中镁含量分析方法研究

本文研究了刚果红分光光度法测定茶叶中镁含量的方法。结果表明：在一定条件下,镁离子含量在0～45μg／25mL范围内遵守朗伯比尔定律,检测限为3．8p,g／L,方法的表观摩尔吸光度为1．27×10^4L·mol^-1·cm^-1,方法的精密度（RSD）小于2．5％,样品加标回收率在96％-103％之间,结果令人满意。     

LC-MSn methods for saccharide characterization of monoglycosyl flavonoids using postcolumn manganese complexation

A simple tandem mass spectrometry method for differentiating isomeric monoglycosyl flavonols, flavones, and flavanones using manganese complexation is reported. Dissociation of the [Mn(II) (L) (L - H)]+ and [Mn(II) (L)2 (L - H)]+ species provides unique fragment ions that allow the identification of the saccharide moiety as glucose, galactose, arabinose, or xylose. The glycosylation site of the flavonoid can also be determined by the fragmentation pathways of the Mn complexes. The Mn complexation method was adapted for on-line liquid chromatography-mass spectrometry analysis and tested using flavonoid extracts from Fuji apples (Malus domestica Borkh. cv. Fuji) and red onions (Allium cepa L.). Using fragmentation data obtained from collisional activated dissociation of the deprotonated flavonoid glycosides and their Mn complexes, the major flavonoid species in these extracts were identified.     

Effect of green synthesised silver nanoparticles on morphogenic and biochemical variations in callus cultures of kinnow mandarin (Citrus reticulata L.)

Citrus reticulata is economically important tree fruit crop in Pakistan, fortified with various nutrients and minerals including Vitamin C and secondary metabolites. Nanotechnology is a twenty‐first century science and deals with production of minute particles termed as nanoparticles. In present study, silver nanoparticles (AgNPs) were synthesised through green method by utilising leaves of Olea europea as main reducing and capping agent. The synthesised AgNPs were characterised through UV visible spectroscopy, SEM, and energy dispersive X‐ray. Furthermore, different concentrations of AgNPs (10, 20, 30 ppm) in combination with Thidiazuron (0.5, 1.0 mg/l) were added onto MS medium to study development and secondary metabolites production in callus culture of C. reticulata. Callus induction percentage (96%) was more in 20 ppm AgNPs and 1 mg/l TDZ concentration. Moreover, high total phenolic, flavonoid contents, and antioxidant activity was observed in 20 ppm AgNPs combined with 0.5 and 1 mg/l TDZ. Enzymatic components (SOD, POD and CAT) were increased in MS medium augmented with 30 ppm AgNPs and TDZ. The total protein content (TPC) was significant in callus cultures treated with TDZ only. This study provides the first evidence of green synthesised AgNPs on callus culture developments and further quantification of biochemical profiling in C. reticula. Inspec keywords: nanoparticles, silver, ultraviolet spectra, scanning electron microscopy, antibacterial activity, agricultural products, nanotechnology, biotechnology, agricultural engineering, nanofabrication, genetic engineering, cropsOther keywords: green synthesised silver nanoparticles, morphogenic variations, biochemical variations, kinnow mandarin, citrus reticulata L, nutrients, minerals, green method, UV visible spectroscopy, energy dispersive X‐ray, MS medium, secondary metabolites production, callus induction percentage, TDZ, flavonoid contents, callus culture developments, capping agent, phenolic contents, tree fruit crop     

In vitro germination and biochemical profiling of Brassica napus in response to biosynthesised zinc nanoparticles

With the progression of nanotechnology, the use of nanoparticles (NPs) in consumer products has increased dramatically and green synthesis is one of the cheapest and eco‐friendly methods to obtain non‐hazardous NPs. In the current research zinc (Zn) NPs synthesis was carried out by using the fresh and healthy leaves of Mentha arvensis L. followed by characterisation through ultraviolet (UV)–visible spectroscopy, X‐ray diffraction (XRD) and scanning electron microscopy (SEM). UV–visible spectroscopy confirmed the green synthesis of ZnNPs, while XRD confirmed the size of NPs, which was 30–70 nm. SEM shows that the shape of ZnNPs was irregular. The effects of green synthesised NPs on two different varieties of Brassica napus were evaluated. Exposure to ZnNPs (5, 15, and 25 mg/l⁻¹) caused a significant increase in root and shoot length of B. napus. The application of NPs significantly improved plant germination and triggered the production of secondary metabolite and antioxidant enzymes. ZnNPs showed a significant increase in chlorophyll, superoxide dismutase, total flavonoid content (TFC) and antioxidant enzymes while total phenolic content was decreased when TFC increased. Thus, it has been concluded from the current study that ZnNPs may possibly trigger the production of antioxidant enzymes and various biochemical compounds.Inspec keywords: zinc, nanoparticles, nanofabrication, ultraviolet spectra, visible spectra, X‐ray diffraction, scanning electron microscopy, particle size, enzymes, molecular biophysics, biochemistry, nanobiotechnology, botanyOther keywords: biochemical profiling, Brassica napus, biosynthesised zinc nanoparticles, nanotechnology, Mentha arvensis L, ultraviolet‐visible spectroscopy, X‐ray diffraction, Zn, biochemical compounds, total phenolic content, total flavonoid content, superoxide dismutase, chlorophyll, antioxidant enzymes, secondary metabolite, plant germination, green synthesis, SEM, scanning electron microscopy, XRD     

毛细管电泳法分析盐酸头孢吡肟中N-甲基吡咯烷含量

建立了一种毛细管电泳间接紫外检测注射用盐酸头孢吡肟中的N-甲基吡咯烷(NMP)含量的方法,讨论了检测波长、电压、进样时间、缓冲溶液的pH值等因素对盐酸头孢吡肟中NMP的影响,获得了优化的分离条件.结果表明,以含0.01 mol/L咪唑和1 mol/L的醋酸(pH=4.7)溶液为背景电解质.在电压为3.00kV,检测波长...     

Identification and quantification of flavonoids in human urine samples by column-switching liquid chromatography coupled to atmospheric pressure chemical ionization mass spectrometry

A rapid and sensitive high-performance liquid chromatographic mass spectrometric (HPLC-MS) method is described for the determination and quantification of 12 dietary flavonoid glycosides and aglycons in human urine samples. Chromatographic separation of the analytes of interest was achieved by column-switching, using the first column (a Zorbax 300SB C-3 column) for sample cleanup and eluting the heart-cut flavonoid fraction onto the second column (a Zorbax SB C-18 column) for separation and detection by ultraviolet and atmospheric pressure chemical ionization MS using single ion monitoring in negative mode. The fragmentor voltage was optimized with regard to maximum abundance of the molecular ion and qualifier ions of the analytes. Calibration graphs were prepared for urine, and good linearity was achieved over a dynamic range of 2.5-1000 ng/mL. The inter- and intraassay coefficients of variation for the analysis of the 12 different flavonoids in quality control urine samples were 12.3% on average (range 11.0-13.7%, n = 24, reproducibility) and the repeatability of the assay were 5.0% (mean, range 0.1-14.8%, n = 12). A subset of 10 urine samples from a human dietary intervention study with high and low flavonoid content was analyzed, and the results are reported.