Determination of 4-hydroxy-2-nonenal in primary rat hepatocyte cultures by liquid chromatography with laser induced fluorescence detection

An HPLC (high performance liquid chromatography) method with laser induced fluorescence (LIF) detection is described for the determination of 4-hydroxy-2-nonenal (HNE) formed from lipid peroxidation in rat hepatocytes. Carbonyl compounds were fluorescently labelled by incubating the hepatocyte samples with a tagging reagent, 4-(2-carbazoylpyrrolidin-1-yl)-7-nitro-2,1,3-benzoxadiazole (NBD-ProCZ), at 60 degrees C for 10 min. The hydrazone derivatives were extracted with a C18 solid phase extraction (SPE) cartridge and separated on a reversed-phase HPLC column. The detection limit was 2.5 fmol or 0.5 nM (5 microL injection) of HNE in the cell homogenate. Method precision (C.V.) was 5% at the 5 nM level. The method has been used to determine free HNE in rat hepatocyte samples treated with several pro-oxidant toxins. A significant HNE increase (from 4 to 27.6 pmol/10(6) cells) was observed with the samples treated by allyl alcohol. The results were in accordance with those for malondialdehyde formation as measured by a thiobarbituric acid (TBA) assay.     

Studies on the determination of diacetyl guanfubase A concentration in rabbit plasma and pharmacokinetics

A gas chromatographic method for monitoring diacetyl guanfubase A in plasma is described. The procedure involved a single solvent extraction of drug from rabbit plasma into ethyl acetate with guanfubase A as an internal standard. The extract was analyzed subsequently on a gas chromatograph equipped with a hydrogen flame ionization detector. The recovery was 86.43% +/- 6.90% (+/- SD); the RSD of within-day and between-day was 2.81%-5.26% and 5.22%-8.24%, respectively; the regression line was linear over the concentration range of 25-200 micrograms/mL, the limit of detection was 10 micrograms/mL. No endogeneous interference was found in chromatograms of the biological samples. This method was applied to the pharmacokinetic study of diacetyl guanfubase A in rabbits.     

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometric analysis of phospholipase A2 and fibrinolytic enzyme, two enzymes obtained from Chinese Agkistrodon blomhoffii Ussurensis venom

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) was used to analyze two enzymes, phospholipase A2 and fibrinolytic enzyme isolated from Chinese Agkistrodon blomhoffii Ussurensis venom. Using sinapinic acid as the matrix, positive ion mass spectra of the enzymes were obtained. In addition to the dominant protein [M + H]+ ions, multimeric and multiply charged ions were also observed in the mass spectra. The higher the concentration of the enzymes, the more multiply charged polymer and multimeric ions were detected. Our results indicate that MALDI-TOFMS can provide a rapid and accurate method for molecular weight determination of snake venom enzymes. Mass accuracies of 0.1 and 0.3% were achieved by analysis of highly dialyzed phospholipase A2 and fibrinolytic enzyme, and these results are much better than those obtained using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. MALDI-TOFMS thus provides a reliable method to determine the purity and molecular weight of these enzymes, which are of potential use as therapeutants.     

双波长K系数—标准加入吸光光度法同时测定锰和锌

研究应用双波长K系数—标准加入吸光光度法同时测定锰和锌二组分混合物.试验确定了锰和锌测定中K_(Mn)与K_(Zn)的回归方程.对合成试样、人发试样测定,结果满意.     

Immobilization of single-stranded deoxyribonucleic acid on gold electrode with self-assembled aminoethanethiol monolayer for DNA electrochemical sensor applications

A synthesized 24-mer single-stranded deoxyribonucleic acid (ssDNA) was covalently immobilized onto a self-assembled aminoethanethiol monolayer modified gold electrode, using water-soluble 1-ethyl-3(3-dimethylaminopropyl)-carbodiimide (EDC). The covalently immobilized ssDNAs were hybridized with complementary ssDNA (cDNA) or yAL(3) gene in solution, forming double-stranded DNAs (dsDNA). Meanwhile, daunomycin as an electrochemical active intercalator in the hybridization buffer solution was intercalated into the dsDNA to form a dsDNA/daunomycin system on the gold electrode surface, which was used for DNA electrochemical sensor. The cathodic waves of daunomycin bound to the double-stranded DNA (dsDNA) by linear sweep voltammetry were utilized to detect the cDNA. The cathodic peak current (i(pc)) of duanomycin was linearly related to the concentrations of cDNA between 0.1 mug ml(-1) and 0.1 ng ml(-1). The detection limit was about 30 pg ml(-1).     

AFM imaging and characterization of latex particles formed by copolymerization of styrene and poly(ethylene oxide) macromonomer

A new type of latex particle was prepared by copolymerization of styrene and poly(ethylene oxide) macromonomer. By controlling the concentration of styrene in reaction mixtures, several latexes with different grain sizes were obtained. The packing patterns of the latex films as well as shapes and sizes of the latex particles were measured with atomic force microscopy (AFM). AFM images revealed that the grain sizes of the latexes increase with increasing concentration of styrene. At a higher styrene concentration (10 wt%), the latex showed a rather homogenous distribution of grain sizes. Lateral force microscopy (LFM) was used to reveal frictional features of latex particles. Contact and non-contact mode AFM were employed to image the same sample of the latex films. The results show that AFM working in non-contact mode can be used to effectively eliminate the horizontal-line-like artifacts, which may obscure AFM images.     

Application of capillary electrophoresis to process monitoring in the manufacturing of semisynthetic penicillins

Application of capillary electrophoresis to monitoring the concentration of material penicillin and the intermediates in the manufacturing process of semisynthetic penicillins was investigated. Factors affecting the precision of analysis were screened and optimised by orthogonal array designs. Compared to conventional HPLC methods, the capillary electrophoresis method gives better resolution and faster sample throughput. Other advantages of the capillary electrophoresis method over HPLC methods include much less consumption of buffer solution and the absence of organic solvents in the analysis.     

二茂钛苄氧基衍生物的合成及性质研究

Ｃｐ２ＴｉＣｌ２及（ＭｅＣｐ）２ＴｉＣｌ２在Ｅｔ３Ｎ或ＮａＮＨ２存在下与苄醇类化合物反应，高产率地合成了６个未见文献报道的二茂钛（Ⅳ）苄氧基衍生物，甲基二茂钛（Ⅳ）苄氧基化合物，经元素分析，ＨＮＭＲ和ＩＲ光谱确定了化合物的结构，并对其部分性质进行了讨论。     

合成1，3－二（3－羟丙基）四甲基二硅氧烷的新方法

用二乙氧基二甲基硅烷与３－氯丙醇反应，合成了新化合物３－氯丙氧基乙氧基二甲基硅烷，然后用格氏反应代替Ｗａｌｔｅｒ的钠缩合反应，最后经水解制备了１，３－二（３－羟丙基）四甲基二硅氧烷，总收率为４２．０％。     

卡尔曼滤波分光光度法同时测定钢样中的硅、磷、砷

研究了在聚乙烯醇存在下,硅、磷、砷钼杂多酸与罗丹明6G形成离子缔合物的反应,建立了能同时测定硅、磷、砷的卡尔曼滤波分光光度法。用于钢样中微量硅、磷、砷的同时测定,操作简便快速,相对误差小于8％。