手性流动相添加剂法拆分安妥沙星对映体

采用L-苯丙氨酸和CuSO_4作为手性流动相添加剂,建立液相色谱法拆分安妥沙星对映体的方法。考察了手性添加剂的种类、浓度及流动相pH等对安妥沙星对映体分离的影响。采用Welch Ultimate XBC_(18)色谱柱(4.6 mm×250 mm,5μm),优化流动相为8 mmol/L L-苯丙氨酸溶液(含4 mmol/L的CuSO_4,pH 3.5)-甲醇(80∶20,V∶V),流速:1.0 mL/min,检测波长:302 nm,结果左、右旋安妥沙星峰达到基线分离,分离度为6.6。     

手性冠醚为手性分离选择剂的胶束毛细管电泳在线富集分离吉米沙星对映体

以手性冠醚为胶束毛细管电泳手性分离选择剂,对吉米沙星对映体药物的在线富集分离进行了研究.考察了阳离子表面活性剂十二烷基三甲基溴化铵浓度、运行缓冲溶液中有机添加剂含量和进样方式对对映体的富集和分离度的影响.使用未涂层毛细管柱(37 cm×51 μm,有效柱长30 cm),45 mmol/L Bis-Tris缓冲液+10 mmol/L十二烷基三甲基溴化铵(DTAB)+1 mmol/L手性冠醚+11%乙腈为运行缓冲溶液(pH=4.0),在紫外检测波长280 nm、运行电压-10 kV、电动进样条件下,对吉米沙星对映体进行在线推扫(sweeping)富集分离,在基线分离的前提下,富集倍数可达600～700倍.吉米沙星浓度为0.3 μmol/L时,两对映体峰高的相对标准偏差<4.0%(n=7).本方法为毛细管电泳在痕量对映体药物分析等方面的应用提供了新方法.     

苯氨基甲酸酯化β-环糊精手性固定相测定中草药中柚皮甙对映体

采用自制的苯氨基甲酸酯衍生化β-环糊精键合SBA-15手性固定相,以甲醇-水作流动相,拆分了柚皮甙对映体;考察了流动相组成、柱温、检测波长等对柚皮甙拆分和测定的影响,优化的色谱条件为:流动相为甲醇-水(55:45,V/V),流速0.5 m L/min,柱温20℃,进样量10μL,检测波长为285 nm。基于上述条件,对中草药化橘红、香橼、枳壳及柚皮中的柚皮甙对映体进行了含量测定。柚皮甙每个对映异构体均在0.5~500μg/m L范围内线性关系良好(r≥0.995),检出限为0.04μg/m L(S/N=3)。以化橘红为例,柚皮甙第一个对映体的加标平均回收率为93.8%和RSD为1.2%(n=5),第二个对映体的加标平均回收率为91.3%和RSD为1.6%(n=5)。测得化橘红、香橼、枳壳和柚皮中柚皮甙两对映体的含量分别为10.42 mg/g和15.84 mg/g,15.39 mg/g和49.52 mg/g,16.53 mg/g和95.80 mg/g,18.47 mg/g和30.98 mg/g。     

毛细管电泳手性分离-激光诱导荧光检测普萘洛尔对映体

用异硫氰酸荧光素衍生普萘洛尔,衍生产物用毛细管电泳分离,激光诱导荧光方法检测。在含有10mmol/L-βCD,50mmol/L硼砂(pH=9.0)的溶液中,普萘洛尔对映体得到了基线分离。本方法线性范围宽(R型:2.0×10-3~1mg/L),灵敏度高(检出限均为1.24μg/L),可用于活体中普萘洛尔对映体的药代动力学研究。     

高效液相色谱手性固定相法拆分和测定乳酸左氧氟沙星中乳酸对映体

建立了高效液相色谱手性固定相法拆分和测定乳酸左氧氟沙星中乳酸对映体的方法。考察了CuSO₄溶液浓度和异丙醇比例对乳酸对映体和左氧氟沙星分离情况的影响。采用Phenomenex 3126(D)-Penicillamine手性色谱柱，优化流动相为2.5 mmol/L CuSO₄溶液-异丙醇(体积比为93∶7),乳酸对映体达到基线分离。以L-乳酸锂和水解后的D-乳酸为标准品，解决了直接采用乳酸为标准品导致测定结果有偏差的问题。L-乳酸和D-乳酸在20～400μg/mL范围内线性良好，相关系数R²分别为09999和0.9998。重复性实验得到的相对标准偏差(RSD)为0.7%～0.8%,回收率为98.77%～100.1%(RSD≤1.0%),准确度和精密度良好。该方法简便，适用于乳酸左氧氟沙星中乳酸对映体含量的测定。     

手性配位交换色谱法拆分普卢利沙星对映体

以L-异亮氨酸和CuSO4作为手性流动相添加剂,采用手性配位交换色谱法拆分普卢利沙星对映体.考察了添加剂的种类、浓度、比例以及流动相pH等因素对拆分的影响.优化的色谱条件为:C18色谱柱,流动相为8 mmol/L L-异亮氨酸和4 mmol/L CuSO4溶液(pH=3.5)-甲醇(68∶32,V/V),流速为1.0 ...     

鼠血中烯丙洛尔对映体的毛细管电泳分离与测定

建立了一种双手性拆分试剂(羟丙基-β-环糊精和羧甲基-β-环糊精)拆分烯丙洛尔对映体的毛细管电泳方法。烯丙洛尔对映体在pH 3.8的80 mmol/L Tris-H3PO4+15 mmol/L羟丙基-β-环糊精(HP--βCD)+5.0 g/L羧甲基-β-环糊精(CM--βCD)条件下获得成功分离。以(1R,2R)-2-氨基-1-苯基-1,3-丙二醇为内标,采用内标法定量,烯丙洛尔对映体在0.25~50 mg/L范围内具有良好线性关系,检出限(S/N=3)为0.25 mg/L,日内、日间RSD均不大于6%,平均回收率为97%~102%。该方法可用于鼠体内烯丙洛尔的药代动力学研究。     

柱切换技术-高效液相色谱法快速检测大鼠血浆中的普萘洛尔对映体

建立了快速检测大鼠血浆中普萘洛尔对映体浓度的柱切换-高效液相色谱法。将自制限进填料柱作为预处理柱,通过直接进样方式,使普萘洛尔对映体在预处理柱上保留,同时除去血浆中的蛋白质等大分子;再通过柱切换技术,使普萘洛尔对映体在键合型纤维素-三(3,5-二甲基苯基氨基甲酸酯)(Chiralcel OD-RH)分析柱上得到手性拆分。通过条件优化,确定切换前预处理流动相为硼酸盐缓冲液(pH 8.5)-甲醇(95:5, v/v),流速为1.0 mL/min;切换后分析流动相为异丙醇-乙醇-0.2 mmol/L硼酸盐缓冲液(pH 8.5)(30:30:40, v/v/v),流速为0.8 mL/min;切换时间为3 min;柱温为25 ℃;检测波长为293 nm。普萘洛尔两对映体在25～500 mg/L的质量浓度范围内具有良好的线性关系(r=0.9995), 3个加标水平(50、100、250 mg/L)的平均回收率为97.89%～101.56%,日内和日间精密度均小于5%。该方法简便、快速、灵敏、准确,适于血浆样本中手性药物的药代动力学研究。     

HPLC法拆分(-)-2(S)-苄基-4-酮-4-(顺式-全氢化异吲哚-2-基)丁酸钙对映体

目的：建立刺激胰岛素分泌的新型降糖药物(-)-2 (S)-苄基-4-酮-4-(顺式-全氢化异吲哚-2-基)丁酸钙对映体的HPLC拆分方法。方法：采用Sumichiral OA-3300手性柱(250 × 4.6 mm I.D., 5 μm), 柱温35℃,以0.05 mol·L-1醋酸铵的甲醇溶液为流动相,检测波长为210 nm。结果：本品两对映体在22分钟内实现良好分离,分离度达3以上,S－异构体分别在0.028 ~ 5.6 μg mL-1和0.03 ~ 6.0 μg mL-1范围内线性关系良好,回归方程分别为：Y=1.32×103x-2.54 (r=0.9997)和Y=1.15×103x-1.78 (r=0.9998),最低检测限分别为0.15 ng和0.10 ng,方法精密度RSD低于1.0% (n=5)。结论：建立的对映体分离方法可用于本品光学异构体的质量控制。     

毛细管电泳手性拆分喹诺酮类药物对映体

采用毛细管电泳法,以铜(Ⅱ)-L-异白氨酸为手性拆分剂,同时分离了氧氟沙星、洛美沙星、司帕沙星和加替沙星四种喹诺酮类药物对映体.考察了手性拆分剂的种类、配比和浓度,缓冲溶液的种类、浓度和pH值,有机添加剂的种类和用量,分离电压等试验条件对分离效果的影响.含8 mmol·L-1L-异白氨酸和4 mmol·L-1硫酸铜的pH 8.5的30 mmol·L-1硼酸钠-盐酸缓冲溶液中,氧氟沙星和加替沙星对映体实现分离;在含20 mmol·L-1 L-异白氨酸,10 mmol·L-1硫酸铜和乙腈(5+95)的pH 9.0的20 mmol·L-1的Tris-硼酸钠缓冲溶液中,司帕沙星、洛美沙星和加替沙星对映体同时实现完全分离.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

Acid hydrolysis of carboxymethylcellulose of low degree of substitution

Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position.     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

Estimation of Kinetic Parameters of Thermal Oxidation of Ilmenite

The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of hematite Fe₂O₃. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the best fitting experimental data. This revised version was published online in August 2006 with corrections to the Cover Date.     

Mechanism of action of base-catalyzed oxygenation of phenol derivatives

Cyclopropyl derivative of 2,6-di-tert-butylphenol is synthesized as a probe to investigate the mechanism of base-catalyzed autooxidation of phenol derivatives. Our study indicates that one electron reduction of molecular oxygen from phenolate gives phenoxyl radical 3, a key intermediate of autooxidation. The coupling of phenoxyl radical and superoxide radical gives peroxylate anion 4 and produces the final epoxy alcohol adduct 6.     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

化学计量中不确定度评定研究进展

测量不确定度是表征合理地赋予被测量之值的分散性的参数。本文针对化学计量不确定度评定基础模型仅适用于线性模型、概率分布为正态分布或缩放位移t分布等局限,介绍了近年来不确定度评定的研究热点:蒙特卡罗方法(Monte Carlo Method,MCM),不确定度评定的来源、评定概念、评估方法及其发展过程,扩大了测量不确定度评定与表示的适用范围。