气相色谱-质谱测定香烟灰中的多环芳烃

采用正己烷-二氯甲烷(体积比为1:1)索氏提取,硅胶柱净化技术,用气相色谱-质谱(GC-MS)的分段选择性离子监测(SIM)对烟灰中多环芳烃(PAHs)进行定性定量分析.通过优化19种PAHs的分离条件,SIM法实现烟灰中19种PAHs的同时测定,检出限达到0.02ng/mL.该法灵敏、准确,适合于烟灰等食品中多环芳烃含量的测定.     

Characterization of Pygeum africanum bark extracts by HRGC with computer assistance

The components of Pygeum africanum bark extracts, used for the treatment of benign prostatic hypertrophy, were characterized by high resolution gas chromatography (HRGC) and mass spectrometry (MS). Among various compounds n-docosyl trans-ferulate was identified and quantitated by HRGC as a derivative of n-docosanol, which is considered to be one of the active components of the extract. The origin of different Pygeum a. extracts can be studied by eigenvector projection of HRGC profiles with computer assistance.     

A Study of the Constituents of the Bark of Chamaecyparis Formosensis Matsum

Sixteen compounds were isolated from the bark of Chamaecyparis formosensis Matsum. These compounds include four categories: (a) long-chain alcohols, acids and esters, (b) sterols and their glucosides, (c) o-methoxyphenol and related compounds, (d) diterpenes of abietane, pimarane, secoabietane and totarane.     

粉煤灰基氧氟沙星分子印迹聚合物的制备及其应用

以工业废料粉煤灰微球为基质,氧氟沙星 (OFL) 为模板分子,采用表面印迹法制备印迹材料MIP。通过紫外光谱法结合理论分析选择实验条件,并对该印迹材料结构、吸附行为进行研究。结果表明,该印迹材料对氧氟沙星具有良好的特异识别性和优良的亲和性。与以硅胶为载体制备的印迹聚合物相比,该材料吸附容量更高和印迹效果更好。将其作为固相萃取填料对鸡产品进行分离富集,与C18柱相比,分离富集效果更好。结合UPLC,对实际样品中氧氟沙星进行分析,回收率为82.0%-96.7%,相对标准偏差低于5.5%,可用于鸡产品中氧氟沙星分离分析。     

流动注射分光光度法测定煤灰中的微量铀

在稀硝酸介质中,以2-(3-羧基苯偶氮)-7-(4-氯-2-膦酸基苯偶氮)-1,8-二羟基-3,6-萘二磺酸(CPA-mK)作为显色剂,建立了一种测定微量铀的流动注射分光光度法,在最佳实验条件下,该方法的线性范围为0-35mg/L,检出限为0.026mg/L,应用该方法测定煤灰样品中的铀,其相对标准偏差为1.8%-3....     

Evaluation of antioxidant activities of the edible and medicinal Acacia albida organs related to phenolic compounds

This study compared phenolic contents and antioxidant activity in different organs of Acacia albida (leaves and bark) and focuses on identification of phenolic compounds of leaves by HPLC-DAD. The analysed organs exhibited differences in total polyphenol contents (100 and 59.5 mg GAE g^? 1 DW). Phenolic contents of leaves were two times higher than those in bark. Ethanolic extracts exhibited good antioxidant activities with IC₅₀ = 26 μg mL^? 1 for DPPH and EC₅₀ = 50 μg mL^? 1 for FRAP. Identification by HPLC-DAD revealed the presence of nine phenolic compounds known for their high antioxidant activity. The results suggested that this species can be used as source of natural antioxidants.     

FEB氦灰问题研究

本文从现有的氦灰输运和排除的实验数据出发，计算了ＦＥＢ的氦灰积累速率，得到了平衡氦灰浓度，另外，从α粒子平衡方程和等离子体功率平衡方程出发得到的结果与直接从实验数据计算得到的结果相一致。最后，用二维Ｍｏｎｔｅ－Ｃａｒｌｏ程序模拟了排灰效率与偏滤器工程结构参数和靶板附近的等离子体参数之间的敏感性关系。     

顺序等离子体光谱技术测定煤飞灰中常量,少量和微量元素

本文采用顺序等离子体光谱技术测定煤飞灰中主要成份（Ｃａ、Ｍｇ、Ｆｅ、Ａｌ、Ｓｉ、Ｎａ、Ｋ、Ｔｉ）及微量成份（Ｃｕ、Ｓｃ、Ｖ、Ｎｉ、Ｂｅ、Ｍｎ）。用扫描光谱法研究了分析线的选择和光谱背景的扣除。试样用密封罐混酸溶解。测定煤飞灰标准样品ＮＢＳ１６３３ａ的结果与标准值一致。方法用于测定新制备的煤飞灰标准参考物。     

Chemical Constituents from the Root Bark of Formosan Zanthoxylum Ailanthoides

Two new N‐isobutylamides, hydroxy lanyuamide I ( 1 ) and hydroxy lanyuamide II ( 2 ), together with one hundred and ten known compounds, have been isolated from the root bark of Formosan Zanthoxylum ailanthoides. These known compounds include twenty coumarins, twenty‐one benzo[c]phenanthridines, ten quinoline derivatives, one aporphine, one purine, seven amides, twelve benzenoids, one lactone, four flavonoids, nine lignans, eight steroids, two chlorophylls, eleven terpenoids and three other compounds, which were determined by means of spectral analyses.     

原子吸收光谱法测定粉煤灰中氧化镁

采用火焰原子吸收光谱法测定粉煤灰中氧化镁的含量。用氢氟酸-高氯酸混合酸分解样品,以氯化锶消除其他元素的干扰。本方法操作简便、再现性好、灵敏度高,氧化镁浓度在0.10—2.00μg/mL之间线性关系良好,检出限可达0.02%,适用于粉煤灰中氧化镁的测定。