气相色谱内标法测洗涤剂中的甲醇

目的:探索适用于含异丙醇成份的手洗餐具用洗涤剂中甲醇的气相色谱内标法的测定方法。方法:洗涤剂样品用N-N二甲基甲酰胺溶解稀释,加入适量丙酮作为内标,定容后取样,用气相色谱仪测定。经DB-624毛细管柱分离,FID检测器检测,内外标混合法定量。结果:本法检出浓度为2.6μg/ml,甲醇在10~400μg/ml浓度范围内呈线性关系,平均回收率为91%~99%,相对标准偏差(RSD)为0.32%~0.79%。结论:本法操作简单,灵敏度高,且数据可靠,可为气相色谱法测定手洗餐具洗涤剂中甲醇提供参考[1]。

Determination of Lycopene Concentration in Dog Plasma by RP-HPLC

A method for determination of lycopene concentration in dog plasma wasestablished. Methods RP-HPLC was used; the mobile phase consisted of methanol-acetonitrile-methylenechloride (40:30:30, V/V) , the wavelength of detection was 472 nm, the column temperature wasambient temperature, and the flow rate was 1.0 mL·min^(-1). Results The standard curve was linearin the range from 0.012 4 to 0.496 μg·mL^(-1) with r=0.9992. The average extraction recovery was97.6% +-4.2%. The intra-day and inter-day RSD were 1.52% -4.95% and 2.31% -7.38%, respectively.Conclusion This method is sensitive, rapid, reproducible, and of good selectivity for the analysisof lycopene in dog plasma.

Solubilities of Nizatidine in Methanol+Water, Ethanol+Water and i-Propanol+Water from 273.15 to 303.15 K

The solubilities of nizatidine in methanol + water, ethanol + water and i-propanol + water mixtures were determined in the temperature range from 273.15 K to 303.15 K at atmospheric pressure by a static analytical method. The general single model was used to correlate the experimental data, which fits the data very well.

Vapor-Liquid Equilibrium Measurements and Modeling for Ternary System Water ＋ Ethanol ＋ 1-Butyl-3-methylimidazolium Acetate

Vapor-liquid equilibrium(VLE) data were measured for ternary system water + ethanol + 1-butyl-3methylimidazolium acetate([bmim][OAc]),in a relatively wide range of ionic liquid(IL) mass fractions up to 0.8.Six sets of complete T-x-y data were obtained,in which the mole fraction of ethanol on IL-free basis was fixed separately at 0.1,0.2,0.4,0.6,0.8,and approximate 0.98.The non-random-two-liquid(NRTL) and electrolyte non-random-two-liquid(eNRTL) equations were used for correlation,showing similar deviations.The ternary VLE was also modeled with the correlation from two data sets,with the mole fractions of ethanol on IL-free basis being 0.1 and approximate 0.98.The VLE data were also reproduced satisfactorily.With the eNRTL model,the root-mean-square deviation for temperature is 0.79 K and that for vapor-phase mole fraction is 0.0094.The calculations are in good agreement with experimental data.The effect of the IL on the VLE behavior of the volatile components is also illustrated.

Simulation of ^(13)C NMR chemical shifts of carbinol carbon atoms using quantitative structure-spectrum relationships

A quantitative structure-spectrum relationship (QSSR) model was developed to simulate 13C nuclear magnetic resonance (NMR) spectra of carbinol carbon atoms for 55 alcohols. The proposed model,using multiple linear regression,contained four descriptors solely extracted from the molecular structure of compounds. The statistical results of the final model show that R2= 0.982 4 and S=0.869 8 (where R is the correlation coefficient and S is the standard deviation). To test its predictive ability,the model was further used to predict the 13C NMR spectra of the carbinol carbon atoms of other nine compounds which were not included in the developed model. The average relative errors are 0.94% and 1.70%,respectively,for the training set and the predictive set. The model is statistically significant and shows good stability for data variation as tested by the leave-one-out (LOO) cross-validation. The comparison with other approaches also reveals good performance of this method.

Study on Vapor Liquid Equilibrium for C_9 Separation by Azeotropic Distillation

In this work,ethylene glycol monomethylether(EE) was chosen as an entrainer for the azeotropic distillation of 1,3,5-trimethylbenzene+1-methyl-2-ethylbenzene system to investigate the influence of the entrainer on vapor liquid equilibrium(VLE) of this system.Three sets of binary VLE data in the system consisting of EE + 1,3,5-trimethylbenzene +1-methyl-2-ethylbenzene were measured using the Dvorak-Boublik still.The binary parameters of NRTL model were correlated by using the likelihood method.The ternary VLE data of the system were measured as well and were predicted by using the binary parameters of NRTL model.The test results indicated that the binary data passed the thermodynamic consistency tests,and the difference between the predicted values of ternary VLE and the experimental data reached the research standard for VLE data.Addition of EE had a great influence on the relative volatility between 1,3,5-trimethylbenzene and 1-methl-2-ethyl-benzene:when the ratio of solvent was 4,and the relative volatility between 1,3,5-trimethylbenzene and 1-methyl-2-ethylbenzene increased from 1.0125(without solvent addition) to 1.283.

Determination of Salt Impurities in MDEA Solution Used in Desulfurization of Highly Sulphurous Natural Gas

The foaming phenomenon of N-methyldiethanolamine(MDEA) solution used in desulfurization process occurs frequently in the natural-gas purification plant. The foaming phenomenon has a strong impact on operation of the process unit. The salt impurities are the main reason for causing the foaming of MDEA solution, so the full analysis of salt impurities is necessary. A method for comprehensive analysis of salt impurities in MDEA solution used in desulfurization process was established. Anions and non-metallic cations of MDEA solution were determined by different conditions of ion chromatograph, respectively. Metallic cations of the solution were detected by atomic absorption spectrophotometer with the N2O-C2H2 flame absorption. The analytical results of salt impurities in the desulfurization solution can provide a theoretical basis for an accurate analysis of the factors affecting the foaming of MDEA to unveil further control measures.

Determination and Correlation of Solubilities of Four Novel Benzothiazolium Ionic Liquids with PF_6^- in Six Alcohols

Four novel benzothiazolium ionic liquids with 6PF?([C1Bth][PF6], [C4Bth][PF6], [C5Bth][PF6] and [C6Bth][PF6]) were synthesized, and the rang of their melting points were determined between 358.35 K-424.05 K. The relationship of their melting points and the length of the straight alkyl chain on cation reflected ‘S' type ten-dency. Then, the solubilities of the four ionic liquids in six lower alcohols(methanol, ethanol, 1-propanol, 2-propanol, 1-butanol and 2-methyl-1-propanol) were measured in the temperature rang of 253.15-383.15 K at at-mospheric pressure with static analytical method, respectively. It was found that [C6Bth][PF6] in all investigated ionic liquids had the largest solubility in six alcohols and the solubility of [C4Bth][PF6] in methanol was very sensi-tive for temperature in 313.15-333.15 K, which was so-called "temperature-sensitivity". This feature is of great significance to their application of catalyzing reaction or extraction process, and makes the recovery and reuse of ionic liquids(ILs) become easier. Moreover, the experimental solubility data were correlated with the modified Apelblat equation and λh equation, respectively. It was found that the result of correlation using two divided tem-perature ranges was better than that of using the whole temperature range.

Anti-anxiety activity of successive extracts of angelica archangelica linn.on the elevated t-maze and forced swimming tests in rats

OBJECTIVE:Angelica archangelica Linn.is widely used in food and liquor preparations and also in Kashmiri folk medicine to reduce anxiety.We evaluated the anxiolytic effect of successive extracts of A.archangelica linn.(SAE) on rats tested in the elevated T-maze test(an animal model of generalized anxiety) at doses that exhibit antidepressant-like activity in humans.METHODS:A.archangelica(1 kg) was subjected to successive extraction in a soxhlet apparatus with solvents [petroleum ether(40-60℃),chloroform,ethyl acetate,methanol and decoction with water] in order of increasing polarity(yield:6.9%,7.3%,5.1%,11.88% and 8.2% w/w,respectively).SAE were evaluated for anxiolytic effects using the elevated T-maze and forced swimming tests in rats.RESULTS:Oral dosing of diazepam(1 mg/kg) and extracts(50,100 and 200 mg/kg) clearly showed an anxiolytic-like profile in the elevated T-maze test:it increased one-way escape and decreased inhibitory avoidance on the first,third and seventh day.In the forced swimming test,imipramine and SAE showed antidepressant-and anxiolytic-like effects as reflected by increased climbing time,swimming time and decreased immobility time on the first,third and seventh day.Aqueous and methanol extracts showed the most,petroleum ether(40-60℃) and chloroform intermediate,and ethyl acetate the least anxiolytic activity(*P<0.05,**P<0.01,***P< 0.001) in both models.CONCLUSIONS:These results suggest the anti-anxiety activity of various extracts of A.archangelica and strongly justify its use in traditional Indian medicine for the treatment of anxiety.