Quantitative measurement of prostaglandins E2 and E3 by selected ion monitoring

A method for the simultaneous quantative analysis of prostaglandin E₂ (PGE₂) and PGE₃ is described. The PG were analyzed by selected ion monitoring as the methyl ester-TMS ether derivatives of PGB₂ and PGB₃, respectively. The internal standard for the quantification of both species was [3,3,4,4-²H₄]PGE₂. A linear response over the range 0.6–50 ng (1.7–143 pmoles) was demonstrated for PGE₃. The chromatographic conditions used (2% SP-2330 column) afforded nearly baseline separation of the prostaglandins. New standard curves for PGE₃ must be developed each time the ion source parameters are changed. In a typical calibration run, the instrumental precision, expressed as coefficient of variation, ranged from 1.1 to 7.2% for PGE₂ (3 to 100 ng injected) and from 1.6 to 11.1% for PGE₃ (1.5–50 ng injected). The method was applied to the PG analysis of rat renomedullary tissues. The recovery of synthetic PGE₂ added to medullary homogenates was 100.5±1.7% (mean±SEM, n=9), and the recovery of PGE₃ was 91.3±1.4% (n=9).     

Extraction of prostaglandins E1, E2 and E3 from human seminal plasma

Isolation of individual prostaglandins of the E group from human seminal plasma consists of three main steps: preliminary purification from other lipids; resolution of this partially purified material into various groups of prostaglandins on a column of silicic acid; and further purification and resolution of various prostaglandins of each group by reversed phase partition chromatography. The last step is time-consuming and has been replaced by a two-step thin layer chromatography: first on silica gel, which ensures purification of the PGEs, followed by argentation thin layer chromatography, which resolves them into E₁, E₂ and E₃ in microgram quantities.     

Biodesulphurization of a coal by packed-column leaching. Simultaneous thermogravimetric and mass spectrometric analyses

This study has two aims: to improve the biodesulphurization of a semi-anthracite by packed-column leaching by reducing the insoluble sulphate on the coal surface, and to determine whether after the combustion of treated and untreated coal, sulphate sulphur is transformed completely into sulphur dioxide or part remains in the ashes without reacting. Combustion tests were analysed by TG-MS. To reduce the precipitation of salts, two parameters are worked on: solution pH, which is reduced to 1.3, and the idle time between washes (ITBW), which is altered. After 125 days of treatment, comparison with the results of previous studies showed that the precipitated salt content was reduced pyritic desulphurization was increased up to 43%, and total desulphurization to 24%.     

Synthesis of prostaglandins (PGE,PGF, PGA and PGB) in human platelets

Human blood platelets, which previously have been shown to possess the necessary enzymic system for the synthesis of prostaglandins E, are also able to synthesize other prostaglandins, namely PGF, PGA and PGB. The synthesis and degradation rate of the prostaglandins were studied by chase experiments. Their synthesis rate was ca. 0.025 nmol acetate incorporated into PGE₁ (and E₂) per 10⁹ platelets, while their degradation rate per hour was ca. 13% (PGE) and 8% (PGF) of the initial amount.     

Simultaneous preconcentration of Cd(II), Cu(II) and Pb(II) on Nano-TiO2 modified with 2-mercaptobenzothiazole prior to flame atomic absorption spectrometric determination

Nano-TiO₂ modified with 2-mercaptobenzothiazole (MBT) was investigated as a new adsorbent for preconcentration of Cd(II), Cu(II) and Pb(II). The metal ions are adsorbed onto nano-TiO₂-MBT, eluted by nitric acid and determined by flame atomic absorption spectrometry. The parameters affecting the adsorption were investigated. Under optimized conditions, the calibration curves were linear in the range of 0.2–25.0, 0.2–20.0, and 3.0–70.0 ng mL⁻¹ for cadmium, copper and lead, respectively. The limits of detection for Cd(II), Cu(II) and Pb(II) were 0.12, 0.15 and 1.38 ng mL⁻¹, respectively. The method was applied to determination of Cd(II), Cu(II) and Pb(II) in water and ore samples.     

反式β-甲基-β-硝基苯乙烯类化合物的制备

提供一种快速高效反式β-甲基-β-硝基苯乙烯类化合物的环境友好合成方法,超声波辅助下利用苯甲醛与硝基乙烷烃反应生成硝基烯烃,得到较高的收率,探索了对合成硝基烯烃影响的各种因素。实验表明,最适反应条件为：原料配比（硝基乙烷：苯甲醛）为1．6：1,反应的催化剂用量用量为7％,反应温度为45℃,反应时间为5h。     

GC-MS内标法测定大豆渣油中维生素E的含量

建立气相色谱-质谱联用仪内标法测定大豆渣油中维生素E的方法。以Agilent-5MS 5%Phenyl MethylSiloxane(30 m×0.25 mm×0.25μm)毛细管气相色谱柱为分析柱,柱温230℃,进样口230℃,检测器230℃,内标法计算维生素E的含量。维生素E线性范围是0.1～2 mg/mL,回收率为95.95%,RSD为3.52%。该方法快速、简便,是测定大豆渣油中维生素E含量的一种较好的方法。     

Simultaneous measurement of flow pattern and mass transfer coefficient in bubble columns

Mass transfer studies were carried out in a bubble column using the chemical method. Catalytic oxidation of sodium sulfite was chosen for the studies and the corresponding specific rates of oxidation were obtained using a stirred cell. Laser Doppler anemometer (LDA) was used to measure the instantaneous velocities in the same stirred cell as well as in bubble columns (100 and i.d.). An efficient algorithm based on the multiresolution analysis of the velocity-time data using wavelets was used for the isolation of data belonging to the gas and liquid phases. Eddy isolation model was used for the characterization of the eddy motion including the estimation of the energy dissipation rate. Using the knowledge of eddy motion, a methodology was developed for the prediction of true mass transfer coefficient (k_L) in a stirred cell as well as in bubble columns. The predicted values of k_L have been compared with the experimental values obtained by the chemical method.     

(E)-2-(1-萘亚胺)苊酮席夫碱的合成及晶体结构

以1,2-苊二酮和甲萘胺为原料合成标题化合物,其结构经1HNMR、MS和单晶X-射线衍射技术表征。实验结果表明,该化合物晶体为单斜晶系,P21/c空间群,化合物分子式为C22H13NO,分子量为307.33,晶胞参数为a=0.825 90(11)nm,b=1.551 4(2)nm,c=1.202 39(16)nm,α=90.00°,β=100.342(4)°,γ=90.00°,V=1.515 6(3)nm3,Z=4,CCDC:1035525。     

Synthesis of 2(E),6(E)-bis(chloromethylidene)-4-thiomorpholinamine-1-oxide and its hydrazones

An efficient method for preparation of earlier unknown S-oxide of 2(E),6(E)-bis(chloromethylidene)-4-thiomorpholinamine by oxidation of 2(E),6(E)-bis(chloromethylidene)-4-thiomorpholinamine hydrochloride with hydrogen peroxide in H₂O or EtOH/H₂O followed by the reaction mixture neutralization with Na₂CO₃ has been described. Interaction of the S-oxide with acetaldehyde, butanal, benzaldehyde, 4-methoxybenzaldehyde and 4-pyridinecarboxaldehyde in EtOH, C₆H₆, in the mixture of acetonitrile and ethanol or ethanol and benzene affords the unknown hydrazones, N-organylmethylidene-2(E),6(E)-bis(chloromethylidene)-4-thiomorpholinamine-1-oxides.     

Selective hydrogenation of (E)-2-hexenal to (E)-2-hexen-1-ol over Co-based bimetallic catalysts

Hydrogenation of (E)-2-hexenal was carried out in a liquid phase using Co-based bimetallic catalysts (M–Co/Al₂O₃, M=Pd, Pt, Ru, Rh, Sn, Fe, or Cu). Pd–Co/Al₂O₃ showed the highest activity among the catalysts tested and catalyzed the hydrogenation of CC bond predominantly to produce hexanal and 1-hexanol. Pt–Co/Al₂O₃ was more active than monometallic Co/Al₂O₃ for the hydrogenation of CO bond. The excellent result, 92% selectivity to (E)-2-hexen-1-ol formation at 90% conversion, was obtained by the hydrogenation over Pt–Co/Al₂O₃ bimetallic catalyst. No improved activities were observed for the other bimetallic catalysts.     

Thermogravimetric/mass spectrometric characterization of the thermal decomposition of (4-O-methyl-D-glucurono)-D-xylan

A thermogravimetric/mass spectrometric (TG/MS) system was used to characterize the thermolysis reactions of (4-O-methyl-D -glucurono)-D -xylan. The mass spectrometric peaks, measured as function of time, were attributed to water, methanol, carbon monoxide, carbon dioxide, formaldehyde, formic acid, acetic acid, acetone, acrolein, 2-furaldehyde, and 3-hydroxy-2-penteno-1,5-lactone. The time derivative of the thermogravimetric curve (DTG) consisted of two partially overlapping peaks, indicating a multistep mechanism. The mass spectrometric intensities of the peaks assigned to methanol and 2-furaldehyde coincided with the first DTG peak, suggesting that the first DTG peak represents both dehydration and fragmentation pathways. Methanol, water, formyl group, and carbon dioxide contributed to both of the DTG peaks. This indicates that the dehydration, decarboxylation, and decarbonylation took place in two steps. The compounds observed only in the second DTG peak and later (acetone, formic acid, formaldehyde, acrolein, acetic acid, and 3-hydroxy-2-penteno-1,5-lactone) are probably products of reactions which occur after the collapse of the original polysaccharide structure.     

气相色谱内标法测定2-甲基吡啶和2-羟乙基吡啶的含量

利用气相色谱内标法测定2-甲基吡啶和2-羟乙基吡啶的含量,以吡啶作为内标物,乙醇作溶剂,使用FFAP毛细管色谱柱和FID检测器,对缩合油进行分离与定量。2-甲基毗啶的线性相关系数为0．9995,标准偏差为0．30,变异系数为0．61％,平均回收率为99．76％;2-羟乙基吡啶的线性相关系数为0．9994,标准偏差为0．31,变异系数为1．35％,平均回收率为99．22％。     

KINETICS MODEL FOR INTERFACIAL REACTION OF COPPER EXTRACTION WITH 1-(2'-HYDROXY-5'-NONYLPHENYL)-l-ETHANONE (E)-OXIME AND 1-(2'-HYDROXY-5'-METHYLPHENYL)-1-DECANONE (E)-OXIME

Abstract

A kinetic model for the interfacial reaction of copper extraction with Individual 1-(2'-hydroxy-5'-nonylphenyl)-1-ethanone (E)-oxime and 1-(2'-hydroxy-5'-methylphenyl)-1-decanone (E)-oxime having the same hydrophobicity was used to interpret the effect of hydroxyoxime partition and interfacial activity upon the rate of copper extraction from acidic sulfate solutions. Due to similar hydrophobicity of studied extractants the proposed model, which is very sensitive to the errors of the partition coefficient determination, cannot support any version of extraction mechanism.     

Convenient and efficient syntheses of 4-hydroxy-2(E)-nonenal and 4-oxo-2(E)-nonenal

Lipid peroxidation products 4-hydroxy-2(E)-nonenal (HNE) and 4-oxo-2(E)-nonenal (ONE) were conveniently synthesized using Wittig and Horner-Wardsworth-Emmons (HWE) reaction. Wittig or HWE reaction between an easily prepared phosphorane or phosphonate with glyoxal dimethyl acetal gave a protected 4-oxo-2(E)-nonenal. Hydrolysis gave 4-oxo-2(E)-nonenal, whereas reduction followed by hydrolysis gave 4-hydroxy-2(E)-nonenal.     

Simultaneous measurement of mass flow rate and charge-to-mass ratio of particles in gas-solids pipe flow

This paper summarizes our research on the theory and application of particle charging in gas-solids pipe flow. The particles moving in a pipe are charged by collisions with the pipe wall. The charge transferred from the particles to the wall per unit time is equal to the electric current flowing from the wall to earth, and the current depends on the mass flow rate and the charge-to-mass ratio. Conversely, these values can be calculated from the electric current using a special technique; i.e., two short pipes that are made of different materials are installed in series with electrical isolation. The principle of the calculation is based on the contact charging between different materials and the charge balance in the system; the simultaneous equations can be solved analytically. This method is applicable to online measurement for polymer powders as well as mineral powders.     

阿西替尼中间体(E)-6-碘-3-(2-(吡啶-2-基)乙烯基)-1-(四氢-2H-吡喃-2-基)-1H-吲唑的合成研究

(E)-6-碘-3-(2-(吡啶-2-基)乙烯基)-1-(四氢-2 H-吡喃-2-基)-1 H-吲唑是阿西替尼的关键中间体,以6-硝基-1 H-吲唑为起始原料,经过碘代、加成、偶联、还原、碘代得到目标化合物。探讨了用微波辐射加热偶联反应的问题,并对各步反应合成条件进行了优化。改进后工艺总收率达42.32%(6-硝基-1 H-吲唑为原料计),收率比文献报道值提高近5%,目标化合物和各中间体经1 H NMR和MS等确证结构。改进后的工艺降低了成本,简单可行,适合工业化生产。     

Effect of 4-hydroxy-2(E)-nonenal on soybean lipoxygenase-1

The oxidation of linoleic acid by soybean lipoxygenase-1 (LOX-1) was inhibited in a time-dependent manner by 4-hydroxy-2-(E)-nonenal (HNE). Kinetic analysis indicated the effect was due to slow-binding inhibition conforming to an affinity labeling mechanism-based inhibition. After 25 min of preincubation of LOX-1 with and without HNE, Lineweaver-Burk reciprocal plots indicated mixed noncompetitive/competitive inhibition. Low concentrations of HNE influenced the electron paramagnetic resonance (EPR) signal of 13(S)-hydroperoxy-9(Z), 11(E)-octadecadienoic acid (13-HPODE)-generated Fe³⁺-LOX-1 slightly, but higher concentrations completely eliminated the EPR signal indicating an active site hindered from access by 13-HPODE. HNE may compete for the active site of LOX-1 because its precursor, 4-hydroperoxy-(2E)-nonenal, is a product of LOX-1 oxidation of (3Z)-nonenal. Also, it was an attractive hypothesis to suggest that HNE may disrupt the active site by forming a Michael adduct with one or more of the three histidines that ligate the iron active site of LOX-1.     

Mass spectra of prostaglandins: II. Trimethylsilyl and alkyloxime-trimethylsilyl derivatives of prostaglandins B1 and B2

The mass spectra of the trimethylsilyl ester trimethylsilyl ether derivatives of prostaglandins B₁ and B₂, and of theirO-ethyl andO-methyl oximes are reported and discussed. The high resolution spectra of these compounds are also considered. These spectra are compared with those of the correspondingd ₉-trimethylsilyl derivatives and of the selectively labeled trimethylsilyl esterd ₉-trimethylsilyl ethers. The base peaks of the spectra of the trimethylsilyl derivatives are formed by sequential loss of C₅H₁₁ (by cleavage of C-15/6) and of CO (from the ring). The spectra of the oxime-trimethylsilyl derivatives are dominated by ions resulting from loss of the alkoxy group of the oxime moiety. For Part I, see Reference 1.