原子吸收光谱法间接测定颜料中微量铟

利用镁－８－羟基喹啉沉淀铟（Ⅲ）置换出定理的镁，火焰原子吸收光谱法测定镁、间接测定铟，线必赤Ｉｎ＾３＋～２．５μｇ／ｍＬ，特征浓度为０．０２μｇ／ｍＬ（相当于１％的净上所对应的溶液浓度），法灵敏度高，操作简单，用于硫化锌基颜料中铟的测定结果满意。     

牛血红蛋白催化荧光猝灭法测定食用油中微量丙二醛

在NH_3·H_2O-NH_4Cl缓冲溶液中,牛血红蛋白催化作用下,过氧化氢氧化L-酪氨酸产生荧光,而丙二醛对该体系产生的荧光有明显的猝灭作用,据此建立一种用荧光猝灭法检测食用油中微量丙二醛的分析方法。在最佳试验条件下,体系的荧光强度变化量(ΔF)与丙二醛质量浓度有良好的线性关系,方法的线性范围为0.208~5.83μg·m L~(-1),检出限为0.140μg·m L~(-1)。将方法应用于食用油中丙二醛的测定,测定结果的RSD为2.5%~3.6%,回收率在93.5%~106%之间。     

色谱指纹谱鉴定食用油品质

随着生活水平的提高,人们对食用油品质的要求也逐渐提高,有必要开发一种快速鉴定食用油品质的方法.食用油的数字化指纹谱的建立借鉴了中药数字化的指纹谱的方法,此方法可应用于食用油的质量控制、真伪鉴别、氧化变质控制等.特征指纹峰的提出保证了鉴定的客观性、科学l生和公正性,也增加了其全面性.食用油的数字化指纹谱的建立为食用油的质量控制提供一种快速、准确、稳定的鉴定方法.     

银杏内酯提取物中微量成分的LC-DAD-ESI-MS分析及结构鉴定

银杏叶ginkgo biloba .L中含有多种二萜内酯和倍半萜内酯.Furukawa.S于1932年首次分离得到银杏内酯混合物;直到1967年,才由Koji Nakanishi和Okabe.K等人鉴定出其中各个成分的结构,并分别命名为Ginkgolide A、B、C、M(简称GA、GB、GC、GM)[1];Weinges K等分别于1969年和1987年分离并鉴定出白果内酯(Bilobalide,BD)[2]和Ginkgolide J[3](GJ).银杏内酯具有抗血小板活化因子(PAF)的作用[4],引起了世界医疗行业的广泛关注.对银杏内酯的HPLC分析常见的检测方法主要有UV、RI和近年出现的ELSD[5],但这些检测方法都有各自的缺陷,UV需在末端检测,易受干扰;RI不适合作梯度洗脱;ELSD灵敏度相对较低.随着对该类化合物的深入研究,发现银杏内酯提取物中尚有一些微量成分,用这些检测方法不足以获得较好的信号响应,本实验以质谱作为检测器,获得了较高的检测灵敏度,结合UV和MS提供的光谱信息,有利于分析鉴别微量成分.     

钛酸锶基陶瓷材料中微量物相鉴定

对具有优良介电性能的高频热补偿多层陶瓷电容器材料（Sr，Ca）TiO3系统进行了研究；X射线粉末衍射法研究表明当瓷料中钛酸锶烧块（简称ST）与钛酸钙烧块（简称CT）摩尔比为nST：nCT≈70：30时，主晶相为具有钙钛矿型结构的（Sr，Ca）TiO3固溶体；微量次晶相为具有钨青铜结构的新化合物铌酸钛钡Ba6Ti2Nb8O30，正交偏光显微分析及材料的介电性能分析进一步验证了这一微量次晶相的存在。     

食用油中非食用油的检验

介绍了食用油中含有的桐油、大麻油、蓖麻油、巴豆油、棉籽油及矿物油等非食用油的检验方法,简便易行,对食用油中含有的非食用油成分的检验有一定的参考作用。     

石油气中微量硫化物的分析

利用石油气分离所得的乙烯及丙烯等,以制造塑料、合成纤维等高分子化合物时,对这些组分中含有的硫化物,均需控制在1～5(毫克/立方米)之间。其分析方法,根据文献报导,有将含硫有机化合物转化为硫化氫及二氧化硫二种途径:前者将含硫有机化合物在高溫下被氫气还原为硫化氫后,再转化为次甲基蓝,     

双酚A中微量杂质的分析

双酚A[2,2-双(4-羟苯基)丙烷]是环氧树脂、聚碳酸酯、改性酚醛树脂和聚砜等高聚物的重要原料,其杂质的含量直接影响产品的性能,因此建立快速而准确的分析双酚A中微量杂质的方法具有重要意义。     

小花玄参中微量金属元素分析

采用干式灰化法分解样品,火焰原子吸收光谱法测定小花玄参不同部位中微量金属元素含量.小花玄参不同部位均含有钙、铁、锰、镁、铜和锌等微量金属元素,其中钙、铁、锰的含量较高,锌、镁的含量较低;6种微量金属元素在块根中含量均高于茎叶;加标回收率在95.3%~104.1%之间,相对标准偏差小于2%,具有较高的精密度与准确度.为小花玄参的质量控制和开发利用提供了重要依据.     

食用油中脂肪酸含量的气相色谱分析

随着人们物质生活水平的提高,国内外对食用油中脂肪酸成分的研究日益重视。为测定食用油中脂肪酸成分,我们用高效毛细管色谱法,使饱和脂肪酸,特别是多种不饱和脂肪酸得到很好的分离和测定。本工作采用快速酯交换法代替常规的脂肪酸甲酯的制备方法,对食用油脂进行了色谱分析并将两种方法所测数据进行对比。     

食用油与人体健康

随着人们生活水平的提高和我国新的食用油标准的实施,食用油越来越受到人们的关注。从食用油的主要化学成分、对人体健康的影响、科学合理的膳食等方面介绍食用油的知识。     

有毒汤样中微量农药杀虫环的鉴定

报道了在广东江门市某工厂发生的食物中毒事件中，对致毒汤样品中农药的分析鉴定过程；采用GC－MS联用分析，被分离出的疑为致毒物质的成分在现有的质谱谱库中检索未能鉴定；通过采用综合分析，将可疑成分提取、分离、柱以谱纯化，结合NMR、ICP－AES和元素分析，确证了汤样中的致毒物质是沙蚕毒素类农药“杀虫环”。     

餐厨废油制备的生物基两性表面活性剂的油水界面性能

以餐厨废油制备了生物基两性表面活性剂,应用界面张力和动态光散射方法,研究了该生物基两性表面活性剂体系的油水界面性能及在溶液中的聚集行为。 在无外加碱条件下,由餐厨废油制备的表面活性剂表现出良好的界面性能,在50~70 ℃以及pH值为7~12的条件下,均可以将油水界面张力降至超低值(<10^-3 mN/m),在不同的油藏模拟地层水中均保持较好的界面活性;分别在50、-20和4 ℃下保存,其界面活性均未受到明显影响。 在水溶液中形成的聚集体的平均流体力学半径为10~30 nm,无机盐离子的加入可使聚集体的粒径上升。 基于其优良的界面性质和可再生来源,由餐厨废油制备的生物基两性表面活性剂在三次采油方面具有重要的应用价值。     

Biodiesel Production by Single and Mixed Immobilized Lipases Using Waste Cooking Oil

Biodiesel is one of the important biofuels as an alternative to petroleum-based diesel fuels. In the current study, enzymatic transesterification reaction was carried out for the production of biodiesel from waste cooking oil (WCO) and experimental conditions were optimized, in order to reach maximum biodiesel yield. Bacillus stearothermophilus and Staphylococcus aureus lipase enzymes were individually immobilized on CaCO₃ to be used as environmentally friendly catalysts for biodiesel production. The immobilized lipases exhibited better stability than free ones and were almost fully active after 60 days of storage at 4 °C. A significant biodiesel yield of 97.66 ± 0.57% was achieved without any pre-treatment and at 1:6 oil/methanol molar ratio, 1% of the enzyme mixture (a 1:1 ratio mixture of both lipase), 1% water content, after 24 h at 55 °C reaction temperature. The biocatalysts retained 93% of their initial activities after six cycles. The fuel and chemical properties such as the cloud point, viscosity at 40 °C and density at 15 °C of the produced biodiesel complied with international specifications (EN 14214) and, therefore, were comparable to those of other diesels/biodiesels. Interestingly, the resulting biodiesel revealed a linolenic methyl ester content of 0.55 ± 0.02% and an ester content of 97.7 ± 0.21% which is in good agreement with EN14214 requirements. Overall, using mixed CaCO₃-immobilized lipases to obtain an environmentally friendly biodiesel from WCO is a promising and effective alternative for biodiesel production catalysis.     

Identification and Characterization of the Yellow Pigment Synthesized by Cupriavidus sp. USMAHM13

Microbial pigments are gaining intensive attention due to increasing awareness of the toxicity of synthetic colours. In this study, a novel polymer-producing bacterium designated as Cupriavidus sp. USMAHM13 was also found to produce yellow pigment when cultivated in nutrient broth. Various parameters such as temperature, pH and ratio of culture volume to flask volume were found to influence the yellow pigment production. UV-Visible, Fourier transform infrared and ¹³C-nuclear magnetic resonance analyses revealed that the crude yellow pigment might probably represent new bioactive compound in the carotenoid family. The crude yellow pigment also exhibited a wide spectrum of antimicrobial activity against Gram-negative and Gram-positive bacteria with their inhibition zones and minimal inhibitory concentrations ranged from 25 to 38 mm and from 0.63 to 2.5 mg/ml, respectively. To the best of our knowledge, this is the first report on the identification and characterization of yellow pigment produced by bacterium belonging to the genus Cupriavidus.     

基于费谢尔判别法的原油、燃料油鉴别技术研究

对原油、燃料油的鉴别方法进行了研究.以来自不同国家和地区的30个原油样品以及不同产地、不同种类的24个燃料油样品中的正构烷烃(n-C7～30)、植烷(Ph)、姥鲛烷(Pr)的含量构成训练集.借助SPSS 16.0进行费谢尔(Fisher)判别分析,建立Fisher判别函数.将判别变量值代入后,得到样本的空间位置,再计算样本至各组重心的距离,据此判断分类情况.结果表明,Fisher判别法可以很好地用于原油和燃料油的鉴别,具有快速、准确等特点.     

原油中双环倍半萜指纹的内标法分析

采用气相色谱-质谱联用(GC-MS)技术,建立了原油中双环倍半萜化合物内标法半定量的分析方法,确定了基于谱图特征、确认离子m/z 123、179、193、207及计算保留指数的组分定性方法,对10种双环倍半萜化合物进行了定性、定量分析.对不同地理位置海上油井平台9个原油的双环倍半萜指纹进行了分析.研究结果表明:原油中双环倍半萜化合物总含量在600～8000μg/g之间;各原油中均以4,4,8,9,9-五甲基十氢化萘(BS3)、4,4,8,9,9-五甲基十氢化萘(BS4)、C16-sesquiterpane(BS8)、8β(H)-升补身烷(BS10)化合物的含量较高,占双环倍半萜总量的60％以上;不同地理位置的原油中双环倍半萜含量的分布规律为:涠洲岛海区＞渤海海区＞进口原油G1、G2;国外原油G3的双环倍半萜含量与渤海原油B3的含量相当,但分布形式不同.同一区块不同采油平台原油中的双环倍半萜指纹非常相似,不同来源的原油中双环倍半萜化合物的分布特征及含量有很大的差异.通过此方法可以实现不同来源原油的准确鉴别.     

Transesterification of Waste Cooking Oil by an Organic Solvent-Tolerant Alkaline Lipase from Streptomyces sp. CS273

The aim of this present study was to produce a microbial enzyme that can potentially be utilized for the enzymatic transesterification of waste cooking oil. To that end, an extracellular lipase was isolated and purified from the culture broth of Streptomyces sp. CS273. The molecular mass of purified lipase was estimated to be 36.55 kDa by SDS PAGE. The optimum lipolytic activity was obtained at alkaline pH 8.0 to 8.5 and temperature 40 °C, while the enzyme was stable in the pH range 7.0?～?9.0 and at temperature ≤40 °C. The lipase showed highest hydrolytic activity towards p-nitrophenyl myristate (C14). The lipase activity was enhanced by several salts and detergents including NaCl, MnSo₄, and deoxy cholic acid, while phenylmethylsulfonyl fluoride at concentration 10 mM inhibited the activity. The lipase showed tolerance towards different organic solvents including ethanol and methanol which are commonly used in transesterification reactions to displace alcohol from triglycerides (ester) contained in renewable resources to yield fatty acid alkyl esters known as biodiesel. Applicability of the lipase in transesterification of waste cooking oil was confirmed by gas chromatography mass spectrometry analysis.     

Stress-Relieving Effects of Sesame Oil Aroma and Identification of the Active Components

(1) Sesame oil aroma has stress-relieving properties, but there is little information on its effective use and active ingredients. (2) Methods: ICR male mice were housed under water-immersion stress for 24 h. Then, the scent of sesame oil or a typical ingredient was inhaled to the stress groups for 30, 60, or 90 min. We investigated the effects of sesame oil aroma on mice behavior and the expression of the dual specificity phosphatase 1 (DUSP1) gene, a candidate stress marker gene in the brain. (3) Results: In an elevated plus-maze test, the rate of entering into the open arm of a maze and the staying time were increased to a maximum after 60 min of inhalation, but these effects decreased 90 min after inhalation. As for the single component, anxiolytic effects were observed in the 2,5-dimethylpyrazine and 2-methoxy phenol group, but the effect was weakened in the furfuryl mercaptan group. The expression levels of DUSP1 in the hippocampus and striatum were significantly decreased in 2,5-dimethylpyrazine and 2-methoxy phenol groups. (4) Conclusions: We clarified the active ingredients and optimal concentrations of sesame oil for its sedative effect. In particular, 2,5-dimethylpyrazine and 2-methoxy phenol significantly suppressed the stress-induced changes in the expression of DUSP1, which are strong anti-stress agents. Our results suggest that these molecules may be powerful anti-stress agents.