Capillary electrophoresis with field-enhanced stacking for rapid and sensitive determination of strychnine and brucine

A new capillary electrophoresis procedure with field-enhanced stacking concentration for the analysis of strychnine and brucine is established. After optimization of the separation and concentration conditions, the two alkaloids can be separated within 5 min and quantified with high sensitivity (The detection limits were 1.0 ng mL(-1) for strychnine and 1.4 ng mL(-1) for brucine). The method was useful for qualitative and quantitative analysis of strychnine and brucine in Strychnos nux-vomica L with recovery of 105.1% for strychnine and 98.4% for brucine.     

Determining the wax content of crude oils by using differential scanning calorimetry

By the use of differential scanning calorimetry (DSC), a new method to measure the wax content of crude oil has been developed. In this paper, the wax content of a crude oil is proposed and proved to be the Q (total thermal effect of wax precipitation in sample) ratio of the crude oil and its corresponding wax obtained by using standard acetone method, i.e. Q_oil/Q_wax. For the 14 studied crude oils with the wax content ranging from 1 to 27 wt.%, the wax contents determined by the presented method are in good agreement with those determined by standard acetone method, with an absolute average deviation of only 0.82 wt.%. This method has an advantage over reported DSC methods in which the exact dissolution or precipitation enthalpy of wax is a must. It is also found that the wax contents determined by either of the two methods show good linear relationship with the total thermal effect Q_oil, with the correlation coefficients over 0.96. According to the empirical correlations, the wax content of a crude oil can be easily determined by using the DSC total thermal effect Q_oil. In addition and more significantly, the new method can be applied to improve the accuracy in determining the amount of precipitated wax in a waxy crude oil at different temperatures.     

Determination of thiol by high-performance liquid chromatography and fluorescence detection with 5-methyl-(2-(<Emphasis Type="Italic">m</Emphasis>-iodoacetylaminophenyl)benzoxazole

A new high-performance liquid chromatographic (HPLC) method for measuring low molecular weight (LMW) thiol-containing compounds, including cysteine (CysH), glutathione (GSH), N-acetylcysteine (Nac), penicillamine (PA), and 2-mercaptoethanol (2-ME), has been developed by using 5-methyl-(2-(m-iodoacetylaminophenyl)benzoxazole (MIPBO) as fluorescence-labeling reagent. The derivatization and separation conditions have been investigated in detail. Detection limits ranging from 3.5 to 15.0 fmol were achieved for the thiols investigated in a 16 min separation with detection wavelengths 310 and 375 nm for the excitation and emission, respectively. The utility of the proposed method has been validated by measuring CysH in human urine samples.     

MoO3、NiO、ZnO在小表面金红石上的分散行为

Dispersion of MoO3, NiO, ZnO on rutile TiO2 with low specific surface area was studied with Mercury Porosimeter, SEM, XPS and Ammonia Extraction method. The dispersion thresholds of MoO3, NiO, ZnO on three rutile TiO2 carriers were obtained with XPS, and com-pared with those on anatase TiO2 with high specific surf are area. Ammonia Extraction method was used to identify the surface oxide species interarting with support surface in different strength and it was found that the proportions of oxides that can not be extracted by ammonia extraction are different for MoO3, NiO and ZnO which are supported on rutile TiO2.     

Influence of ultrasonic field on microcystins produced by bloom-forming algae

Under the background of algae removal and growth inhibition by ultrasonic irradiation, the effects of ultrasonic irradiation on removal of Microcystis, the concentration variation of microcystins (MC) produced by Microcystis in Microcystis suspension, and sonochemical degradation of microcystins in water, were studied in the paper. The results showed that ultrasonic irradiation could efficiently inhibit the growth of Microcystis, and ultrasonic irradiation shorter than 5 min would not introduce the increase of microcystins dissolved in Microcystis suspension simultaneity. Also, microcystins dissolved in Microcystis suspension would not increase as ultrasonic power increasing. Further research showed that microcystins were effectively degraded in ultrasonic fields. After 20 min ultrasonic irradiation at 150 kHz and 30 W, the removal rate of microcystins reached 70%.     

Three-component one-pot total syntheses of glyantrypine, fumiquinazoline F, and fiscalin B promoted by microwave irradiation

A microwave-promoted three-component one-pot reaction has been developed to provide access to the core pyrazino[2,1-b]quinazoline-3,6-dione (1) scaffold, which is common to several families of alkaloids with significant biological activities. By adapting this synthetic strategy through the use of selected Boc-amino acids and amino acid esters, we have accomplished highly efficient and concise total syntheses of glyantrypine (2), fumiquinazoline F (3), and fiscalin B (5), achieving overall yields of 55, 39, and 20%, respectively.     

羟基锆及锆铝交联粘土的合成与表征

制备了锆交联粘土和锆铝交联粘土。锆交联粘土制备条件的研究表明，直接用ＺｒＯＣｌ２．８Ｈ２Ｏ水溶液作交联剂，延长老化时间和增大交联剂浓度有利于制备大比表面积高温有序的锆交联粘土。     

Er:Yb:KGW激光晶体生长及缺陷研究

采用顶部籽晶(TSSG)法生长ErYbKGW晶体.通过研究助熔剂的种类、组成与溶质的比例关系对晶体生长的影响,设计了合理的工艺条件转速30～40 r·min-1;拉速1～2 mm·d-1;降温生长速率0.05 ℃·h-1;降温速率15 ℃·h-1;生长周期15～20 d.通过对晶体缺陷的观察分析认为,晶体裂缝及包裹物等缺陷与生长工艺条件密切相关,应尽量减少生长过程中的温度、浓度及生长速度的波动,保持晶体的稳态生长.     

Luminescence 3D-ordered porous materials composed of CdSe and CdTe nanocrystals

The luminescence porous materials of CdTe or CdSe nanocrystals (NCs) were prepared by filling the corresponding NCs into the voids of colloidal crystal by co-deposition of polymer beads and NCs. After removing the beads with tetrahydrofuran (THF), the 3D-ordered porous materials of CdTe (or CdSe) NCs were obtained. The wavelength of maximum photoluminescence of the NCs porous material shows obvious red shift compared with their aqueous dispersion. Under the excitation of high-energy electron the porous materials of CdTe and CdSe NCs will emit photons that can be collected to form a cathode luminescence (CL) image.