熔融萘萃取铁(Ⅱ)-4,7-二苯基-1,10-菲啰啉-四苯硼酸盐三元络合物光度法测定铁

研究了以熔融萘作为萃取剂,以4,7 二苯基 1,10 菲口罗啉作为显色剂,测定天然水中微量铁的分光光度法。在pH4的条件下,铁(Ⅱ)与4,7 二苯基 1,10 菲口罗啉和四苯硼酸盐能够形成红色三元络合物。在熔融萘存在下,此络合物可以迅速萃入熔融萘。将含有络合物的萘冷却、固化、分离,配制成25mL丙酮溶液,对其进行分光光度分析。实验表明,该络合物最大吸收波长为534nm,摩尔吸光系数和桑德尔灵敏度分别为2×104L·mol-1·cm-1和0.0025μg/cm2,铁(Ⅱ)的质量浓度在0～2 0μg/mL的范围内符合比耳定律。大多数常见离子不干扰测定。已应用于天然水中微量铁的测定。     

近红外光谱法同时测定银杏提取液中总黄酮和总内酯含量

采用傅里叶变换近红外透射光谱和偏最小二乘法,对银杏提取液中总黄酮和总内酯的含量进行了定量测定。所建立的数学模型对校正集样本的银杏总黄酮和总内酯复相关系数(MR)分别为O．998和o．986;对预测集样本的银杏总黄酮和总内酯复相关系数分别为0．983和0．971,标准回收率分别为95．71％～103．3％和95.29％～104.6％,相对标准偏差(RSD)分别为2．44％和3．19％。结果表明,近红外光谱测定银杏提取液中总黄酮和总内酯含量具有快速、准确的优点,有望应用于银杏提取过程的中间控制和大批量产品的检测。     

Simple quality assessment approach for herbal extracts using high performance liquid chromatography-UV based metabolomics platform

A lack of adequate or accepted research methodology has been a major obstacle to study herbal medicines. In this study, instead of the prevalent hyphenated chromatographies, common high performance liquid chromatography equipped with ultraviolet detector (HPLC-UV) and multivariate statistical analysis were utilized to assess the qualities of total flavones of sea buckthorn (TFS), an 85% ethanol extract of the sea buckthorn berries. Two complementary HPLC-UV methods were developed, validated and combined to comprehensively determine the ingredients in TFS. Principal component analysis (PCA) and partial least square-discriminant analysis (PLS-DA) of the combined analytical data showed that the six batches of TFS could be well differentiated. Hierarchical cluster analysis (HCA) using Ward's minimum variance method of the PLS-DA loading matrix demonstrated the known ingredients (quercetin, kaempferol, isorhamnetin, oleanolic acid and ursolic acid) and three unknown ingredients in TFS significantly contributed to the quality differences. A PLS regression model indicated that the results of the present method correlated well with the content of total flavones, which is now the quality control approach of TFS. Results from this study indicated that the proposed method is reliable for the quality reassessment of some widely used herbal extracts.     

On-line identification of 4″-isovalerylspiramycin I in the genetic engineered strain of S. spiramyceticus F21 by liquid chromatography with electrospray ionization tandem mass spectrometry,ultraviolet absorbance detection and nuclear magnetic resonance spectrometry

LC-hyphenated techniques were applied to the on-line identification of isovalerylspiramycin I (isp I), a spiramycin-like macrolide in the crude extract of fermentation broth from a genetically engineered strain of S. spiramyceticus F21. In the structural characterization of the large molecular secondary metabolite of isp I, LC–DAD-UV–ESI-MSⁿ analysis played a crucial role, and stop-flow LC–¹H NMR measurement, with bitespiramycin used as reference, was a valuable complement approach. This rational approach proved to be an efficient means for the rapid and accurate structural determination of known microbial secondary metabolites, by which targeted isolation of component(s) of interest can be subsequently performed for further biological and pharmacological studies in drug development.     

Estimating Aluminum leaching from Aluminum cook wares in different meat extracts and milk

A method of estimating Al leaching from Al cook ware in some meat extracts and liquid milk was investigated. In the present work four kinds of Al cook wares from four countries were chosen from the local market. Extracts of boiled meat (lamb, chicken, and fish) were used to make 10–50% (w/v) concentrations. In addition liquid fresh milk and long life milk were diluted to make 10–50% (v/v) concentrations. Weight loss (WL) method, atomic absorption, polarization method, and surface study were applied. The “estimated” Al intake per person from WL in 30% meat extract and milk range from 8.16 to 12.75 mg/h with fish extract having the highest leaching and chicken extract having the lowest leaching. Atomic absorption gave comparable results to that of WL. Comparing the present results with the Provisional Tolerance Weekly Intake of Al approved by the FDA/WHO shows that Al leaching from Al cook wares may add high doses of Al into the diet.     

Development of a novel label-free amperometric immunosensor for the detection of okadaic acid

Okadaic acid (OA), a lipophilic phycotoxin is mainly produced by toxigenic dinoflagellates. The need to develop high performing methods for OA analysis able to improve the traditional ones is evident. In this work, a novel experimental methodology for label-free detection of OA was developed. Protein G magnetic beads (protein-G-MBs) modified gold electrode was used to immobilize anti-OA monoclonal antibody (anti-OA-MAb). Preliminary, colorimetric tests were performed in order to validate protein-G-MBs and anti-OA-MAb reaction. Electrochemical detection was carried out by differential pulse voltammetry in ferri/ferrocyanide solution. The limit of detection value obtained (0.5 μg L⁻¹) validated the developed electrochemical immunosensor as a promising tool for routine use. The matrix effect and the recovery rate were also assessed with real samples, showing a good percentage of recovery.     

神华煤直接液化残渣超临界溶剂萃取研究

利用甲苯、苯和乙醇三种溶剂在反应釜中对神华煤直接液化残渣进行了超临界溶剂萃取,考察了压力、温度、萃取时间、溶剂/残渣比等对萃取产物收率和重质液体萃取组成的影响。结果表明,以甲苯为溶剂进行萃取时,萃取时间对重质液体产率及HS和A收率的影响不大,而温度、压力以及溶剂/残渣质量比都会影响萃取产物的产率及组成。溶剂超临界萃取过程中,有其他组分向HS组分转化,提高了HS的收率。三种溶剂中,苯显示了和甲苯相似的萃取性能,而乙醇的萃取性能相比苯和甲苯则较差,但乙醇萃取得到的重质液体中轻质组分含量高于苯和甲苯。萃取过程中,残渣中的灰分和硫分主要富集至萃取残渣中。     

Separation of amino acids in plant tissue extracts by capillary zone electrophoresis with indirect UV detection using aromatic carboxylates as background electrolytes

Summary Amino acids in extracts of plant tissue were separated and detected by capillary zone electrophoresis (CZE) with indirect UV detection. Various aromatic carboxylates such as salicylate, benzoate, phthalate and trimellitate were investigated as background electrolytes (BGEs). A BGE of benzoate gave the best resolution and detector response. Amino acids were separated at a highly alkaline pH to charge amino acids negatively. Separation was achieved by the co-electroosmotic flow (Co-EOF) by the addition of the cationic surfactant myristyltrimethyl-ammonium bromide (MTAB) to the electrolyte. The condtions affecting the separation of amino acids, including electrolyte pH, concentrations of both benzoate and MTAB, were investigated and optimised. Separation of a mixture of 17 amino acids at pH 11.20 with indirect UV detection at 225 nm was achieved with a BGE of 10 mM benzoate containing 1.0 mM MTAB at pH of 11.20. Detection limits ranged between 10 and 50 μM. The proposed method was demonstrated by the determination of amino acids in extracts of Eucalypt leaves with direct injection of samples.     

凤凰竹叶黄酮类物质提取条件的优化

天然植物黄酮类物质具有消炎、消肿、降压、降血脂,以及清除氧自由基等多种功能,其提取物质已用于食品、药品、化妆品等产品中。