毛细管区带电泳法测定复方甘草片中的甘草酸、甘草次酸、吗啡和苯甲酸钠

 在紫外检测波长为 2 2 8nm、电压为 14kV、背景电解质为 5 0mmol/L硼砂溶液、内标为氢氯噻嗪的条件下 ,用毛细管区带电泳法对复方甘草片中的甘草酸、甘草次酸、吗啡和苯甲酸钠进行了定量分析。结果甘草酸、甘草次酸、吗啡和苯甲酸钠的相对峰面积 (组分与内标的峰面积之比 )与各自的质量浓度之间呈良好的线性关系 ,上述 4种组分的平均回收率分别为 98 2 % ,97 3% ,97 1%和 97 5 %。方法简便、快速、准确。     

高效液相色谱-二级管阵列检测器法测定化妆品中邻苯二甲酸酯

用甲醇将化妆品样品超声提取15min,离心、过滤,以XDB-C18分析枉分离分析,二级管阵列检测器检测,结合保留时间和光谱定性分析,采用高效液相色谱法测定化妆品中的邻苯二甲酸酯,外标法定量。邻苯二甲酸酯邻苯二甲酸丁基苄基酯（BBP）、邻苯二甲酸二丁酯（DBP）、邻苯二甲酸二（2-乙基已）酯（DEHP）在0．5-10．0mg／L浓度范围内均有良好的线性关系,相关系数r〉0．9998。BBP,DBP,DEHP在1．000,2．000mg／L添加水平的回收率为92％-105％,相对标准偏差（RSD）小于4％0=6）,检出限分别为14,12,6mg／kg。该方法适用于化妆品中BBP,DBP和DEHP含量的检测。     

新型除草剂丙酯草醚A环14C均标记合成和鉴定

以U-¹⁴C-对氨基苯甲酸为前体, 通过酯化、缩合、还原和取代四步反应获得了A环¹⁴C均标记的丙酯草醚, 用PHPLC对其进行纯化. 采用HPLC-MS(ESI), MS(EI)和¹H NMR验证了其结构, 通过HPLC(外标法)确定其化学纯度大于98%; HPLC-LSC和TLC-IIA两种方法分析表明, 其放射化学纯度大于98%, 其比活度为1.089±0.011 mCi/mmol. 合成的化学收率和放化收率均为53%.     

2-(对烷氧基苯甲酸酯基或对烷氧基苯丙烯酸酯基)-5-氧-2,5-二氢呋喃化合物的合成与液晶性质研究

Two series of p-alkoxybenzoates Ia-If and p-alkoxycinnamates IIa-IIf, each species beating one terminal furanone, have been synthesized and characterized by IR, ^13C NMR, ^1H NMR, MS spectra and elemental analysis. The mesogenic properties of both series of furanones have been studied by polarizing optical microscopy and differential scanning calorimetry （DSC）. The relationship between structures and mesogenic properties was discussed. The results show that the increased alkoxy chain length （C7-C12） and the bridging groups between the benzene ring and the furanone ring affected the mesomorphic properties greatly, and the two series of furanones might display monotropic or enantiotropic nematic （N） or semetic C （SmC） mesophases and different mesomorpic phase temperature ranges corresponding to different carbon chain length.     

环戊二烯掺杂乙烷桥联有序介孔材料的制备、表征及应用

 以单硅酯 (2-(环戊基-1,3-二烯基) 乙基) 三乙氧基硅烷 (TEECp) 和含有亚乙基桥键的硅酯 1,2-二 (三乙氧基硅基) 乙烷为硅源, 以三嵌段共聚物 P123 为模板剂, 通过调节 TEECp 预水解时间, 采用共聚法合成了环戊二烯掺杂乙烷桥联材料 (Cp-PMO), 并采用小角 X 射线衍射、N2 物理吸附、透射电镜、红外光谱和热重等技术对样品进行了表征. 结果表明, 环戊二烯基被成功引入到乙烷桥联材料中, 所得 Cp-PMO 样品具有高度有序的二维六方介孔孔道, 热稳定性较高; 随着材料中环戊二烯含量的增加, 其有序性降低, 孔径、比表面积和孔体积均有所减小, 孔壁逐渐增厚. 在乙酸乙酯与正丁醇的酯交换反应中, Cp-PMO 样品表现出较高的催化活性. 当该样品中环戊二烯含量为 30% 时, 乙酸乙酯转化率和乙酸丁酯收率分别可达 19.3% 和 10.6%.     

Fast and sensitive high performance liquid chromatography analysis of cosmetic creams for hydroquinone, phenol and six preservatives

A fast and sensitive HPLC method for analysis of cosmetic creams for hydroquinone, phenol and six preservatives has been developed. The influence of sample preparation conditions and the composition of the mobile phase and elution mode were investigated to optimize the separation of the eight studied components. Final conditions were 60% methanol and 40% water (v/v) extraction of the cosmetic creams. A C18 column (100 mm × 2.1 mm) was used as the separation column and the mobile phase consisted of methanol and 0.05 mol/L ammonium formate in water (pH=3.0) with gradient elution. The results showed that complete separation of the eight studied components was achieved within 10 min, the linear ranges were 1.0-200 μg/mL for phenol, 0.1-150 μg/mL for sorbic acid, 2.0-200 μg/mL for benzoic acid, 0.5-200 μg/mL for hydroquinone, methyl paraben, ethyl paraben and propyl paraben, butyl paraben, and good linear correlation coefficient (≥0.9997) were obtained, the detection limit was in the range of 0.05-1.0 μg/mL, the average recovery was between 86.5% and 116.3%, and the relative standard deviation (RSD) was less than 5.0% (n=6). The method is easy, fast and sensitive, it can be employed to analyze component residues in cosmetic creams especially in a quality control setting.     

Spectral Properties and Solubilization Location of 2'-Ethylhexyl 4-(N,N-Dimethylamino)benzoate in Micelles

在阳离子、非离子和阴离子表面活性剂胶束溶液中,研究了4-(N,N-二甲氨基)苯甲酸2'-乙基己基酯(EHDMAB)的双重荧光和紫外吸收．当EHDMAB增溶在不同的胶束溶液中,紫外吸收增强,在离子型胶束溶液中,可观察到具有较长波长的EHDMAB分子内扭转电荷转移(TICT)荧光,相反,在非离子型胶束溶液中,可观察到具有较短波长TICT荧光,特别是位于阳离子胶束Stern层中的吡啶阳离子可强烈猝灭EHDMAB分子的双重荧光,所吸收的紫外辐射主要通过TICT荧光和非辐射去活化衰减．按照EHDMAB分子TICT荧光在有机溶剂中的极性依赖性,EHDMAB分子的4-(N,N-二甲氨基)在离子型胶束和非离子型胶束中处于不同的极性环境;根据EHDMAB和表面活性剂分子的结构和大小分析,EHDMAB分子的4-(N,N-二甲氨基)应朝向胶束的极性头基团,而2'-乙基己基链则朝向疏水性的胶束内核．动态荧光猝灭测量为EHDMAB分子在不同胶束中的位置进一步提供了佐证．     

A computational study of stereospecifity in the thermal elimination reaction of menthyl benzoate in the gas phase

This paper reports a theoretical study, at the B3LYP/6–31 + G(d,p) and M05‐2X/6–31G + (d,p) levels, on the thermal decomposition of menthyl benzoate (2‐isopropyl‐5‐methylcyclohexyl benzoate). It undergoes a unimolecular first‐order elimination to give 3‐menthene (1‐isopropyl‐4‐methylcyclohexene), 2‐menthene (3‐isopropyl‐6‐methylcyclohexene), and benzoic acid. We studied two possible mechanisms trying to explain the formation of 2‐ and 3‐menthene, via six‐membered or four‐membered cyclic transition states. Rate constants were calculated at two temperatures, 587.1 and 598.6 K, and they agree well with the experimentally determined values. We verify that 3‐menthene is the product mainly formed at both temperatures. The progress of the reactions has been followed by means of the Wiberg bond indices. Intrinsic reaction coordinate (IRC) calculations have been carried out to verify that the localized transition state structures connect with the reactants and products and also to verify that the parent compound, menthyl benzoate, is taking the cis‐configuration needed in the reaction. Copyright © 2009 John Wiley & Sons, Ltd.     

Photodegradation of butyl acrylate in the troposphere by OH radicals: kinetics and fate of 1,2‐hydroxyalcoxy radicals

The rate constant of the reaction of OH radicals with butyl acrylate was studied for the first time using an atmospheric simulation chamber at 298 K and ～750 Torr of air or nitrogen. The decay of the organics was followed using a gas chromatograph with a flame ionization detector (GC‐FID), and the rate constant was determined using a relative rate method with different references. The obtained average value of (1.80 ± 0.26) × 10^?11 cm³ molecule^?1 s^?1 is in agreement with previous determinations of the rate constants of OH radicals with acrylates and methacrylates in the literature. Additionally, product identification under atmospheric conditions was performed for the first time by the GC‐MS technique. Butyl glyoxalate was observed as the degradation product in accordance with the addition of OH to the less substituted carbon atom of the double bond, followed by decomposition of the 1,2‐hydroxyalkoxy radicals formed. Room temperature rate coefficient was used to estimate the atmospheric lifetime of the ester studied. Reactivity trends are discussed in terms of the substituent effects and the length of the hydrogenated chain of the ester. The atmospheric persistence of BUAC was calculated taking into account the experimental rate constant obtained. Copyright © 2008 John Wiley & Sons, Ltd.