献血员血清中20种元素的ICP-MS测定

用电感耦合等离子体质谱（ＩＣＰ－ ＭＳ） 测定献血员血清中２０ 种元素, 采用多元素内标法校正基体效应引起的系统误差, 加入内标元素Ｓｃ 、Ｉｎ 和Ｔｌ 分别校正质量数＜ １００ 、１００ ～１８０ 和＞ １８０ 的元素测定, 用牛血清标样ＧＢＷ ０９１３１ 为质控标准物质, 检验方法的可靠性。 测定了献血组和健康对照组血清中微量元素含量, 进行数理统计, 检验其差异性。     

美洛昔康的合成

从糖精钠出发,经４步反应合成美洛昔康,总收率４３．５％,首次分离,纯化了甲基化反应的重要副产物,经元素分析、氢谱,质谱确定为双甲基化产物。用重结晶方法对单甲基化物进行纯化。     

苯并呋喃并香豆素的合成及其钙拮抗活性初步研究

１引言香豆素是一类具有重要生理活性的天然产物,具抗凝血、抗肿瘤、抗病毒等多种活性,最近又发现某些香豆素化合物具有钙桔抗活性［‘,’］。目前对此类物质钙站抗活性的研究国内外还开展较少。我们设计合成了一系列苯并吠哺并香豆素化合物,选取其中三个（;、Ｄ。、Ｄ３）＄０一个简单二羟基香豆素（Ｃ。）经放射性‘’Ｃａ跨膜流动技术测定,表明其对电压依赖性钙离于通道（ＰＤＣ）均有较显著阻滞作用（见表１）。其中Ｄ。未见文献报道,其结构经ＮＭＲ、ＩＲ、ＭＳ确证。已知物Ｄ;、Ｄ。和Ｃ。的钙通道阻滞活性尚未见其它文献报道…     

舞花姜的化学成分

舞花姜（Ｇｌｏｂｂａｒａｃｅｍｏｓａｓｍｉｔｈ）为姜科舞花姜属植物,产于我国南部、西南部等地。其根和果实在民间药用,有健胃、消炎的功能,用于治疗胃炎、消化不良、急慢性肾炎等［１］。尚未见有关舞花姜属植物化学成分和药理活性的研究报道,为此我们对其地下部分的化学成分进行了研究。乙醇提取物的石油醚可溶部分经硅胶柱和萄聚糖凝胶柱层析分离得到五个化合物,经光谱鉴定为木栓酮（ｆｒｉｅｄｅｌｉｎ１）,ｃｙｃｌｏｅｕｃａｌｅｎ－ｏｌ（２）、３－羟基－豆甾－５烯－７－酮（３－ｈｙｄｒｏｘｙ－ｓｔｉｇｍａｓｔ－５－…     

轻质石油产品电导率仪检定系统分析

论述研制轻质石油产品电导率仪检定系统的必要性,介绍各级检定标准装置的原理和检定方法。     

Micellar effects on the electrochemistry of dopamine and its selective detection in the presence of ascorbic acid

The electrochemistry of dopamine (3-hydroxytyramine) was studied by cyclic voltammetry at a glassy carbon electrode in the presence of cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) micelles at different pH. The anodic peak potential (E(pa)) and peak current (I(pa)) were found to be remarkably dependent on the charge and the concentration of the surfactant. The E(pa) and I(pa) change abruptly around the critical micellar concentration (CMC) of the surfactants and reach a plateau above the CMC. The E(pa) at the plateau shifts to more positive values in the cationic CTAB micellar solution, e.g. from 180 mV vs SCE in aqueous solution at pH 6.8 to 410 mV in CTAB micelle, whilst it shifts to less positive values in the anionic SDS micellar solution, e.g. 150 mV at pH 6.8. Therefore, the overlapped anodic peaks of dopamine and ascorbic acid in the mixture of the two compounds in aqueous solutions can be separated in CTAB micelles since the micelle shifts the E(pa) of ascorbic acid to less positive values. The two peaks are separated by ca. 400 mV at pH 6.8 in CTAB micelle, hence dopamine can be determined in the presence of 100 times excess of ascorbic acid. In SDS micelle and in the presence of ascorbic acid, the I(pa) of dopamine is greatly enhanced due to the catalytic oxidation of the latter that enables quantitative determination of both compounds.     

Determination of rare earth impurities in high purity gadolinium oxide by inductively coupled plasma mass spectrometry after 2-ethylhexylhydrogen-ethylhexy phosphonate extraction chromatographic separation

A method was developed for the determination of rare earth impurities in high purity Gd(2)O(3) by inductively coupled plasma mass spectrometry (ICP-MS). The matrix suppression effect of Gd(2)O(3) on signals of rare earth impurities was compensated for by Re internal standardization. The spectra overlap interferences from GdH, GdO, GdOH(n) (n=1-3) on Tb, Tm, Yb and Lu were eliminated by 2-thylhexylhydrogen-2-ethylhexy phosphonate (EHEHP) extraction chromatographic separation. The detection limits for REEs were 0.005-0.017 ng ml(-1) in solution and 0.002-0.05 mug g(-1) in solid. Recoveries of spiked sample for REEs were from 88 to 121% with the precision of 1.0-7.5% RSD. Determination of trace REEs in two Gd(2)O(3) samples were performed. The method can be applied to analysis of 99.99-99.9999% high purity Gd(2)O(3).     

Heterolytic cleavage of a beta-phosphatoxyalkyl radical resulting in phosphate migration or radical cation formation as a function of solvent polarity

[formula: see text] The 2-(diethylphosphatoxy)-2-(p-methoxyphenyl)-1,1-dimethylethyl radical (1) reacted to give the benzylic radical product from phosphate migration or a radical cation (or a mixture of the two) as a function of solvent. Smooth acceleration in rates of reactions of 1 in solvents of increasing polarity and consistent entropies of activation indicate that radical 1 reacts by common mechanism irrespective of the final products formed, specifically by initial heterolysis to a radical cation-phosphate anion pair.     

Using molecular quantum similarity measures as descriptors in quantitative structure-toxicity relationships

In this paper molecular quantum similarity measures (MQSM) are used to describe molecular toxicity and to construct Quantitative Structure-Toxicity Relationships (QSTR) models. This study continues the recently described relationships between MQSM and log P values, which permits to use the theoretical MQSM as an alternative to the empirical hydrophobic parameter in QSPR studies. In addition a new type of MQSM is presented in this work: it is based on the expectation value of electron-electron repulsion energy. The molecular properties studied here, as application examples are aquatic toxicity, toxicology on Bacteria and inhibition of a macromolecule employing four different molecular sets.