超高效液相色谱法测定绿茶中5种儿茶素

建立了绿茶中儿茶素、表儿茶素、表儿茶素没食子酸酯、表没食子儿茶素和表没食子儿茶素没食子酸酯含量的超高效液相色谱紫外检测方法。样品采用70℃甲醇-水溶液热水浴下提取。色谱柱为Waters Acquity-BEH C18柱(1.7μm,50 mm×2.5 mm);流动相为乙腈和0.1%甲酸,采用梯度洗脱,乙腈洗脱浓度和时间为:9%(0 min)-9%(4 min)-12%(6 min)-25%(8 min)-9%(9 min)-9%(9.5 min);流速0.25 mL/min;柱温30℃;进样量10μL;检测时间9.5 min;二极管阵列检测器;检测波长278 nm。实验结果表明,在该色谱条件下,5种儿茶素能达到较好的基线分离效果,样品回收率在95.0%～105.0%之间,相对标准偏差(RSD)为1.7%～3.0%(n=5)。     

高效液相色谱法测定固体废物中2,4-二硝基氯苯和对硝基氯苯的含量

利用高效液相色谱测定固体废物中2,4-二硝基氯苯和对硝基氯苯的含量。色谱条件为:色谱柱,InertSustain C18反相色谱柱25 cm×4.6 mm(5μm);流动相,采用水和乙腈梯度洗脱;柱温,40℃;流速,1.0 mL/min;进样体积,10μL;二极管阵列检测器波长,250 nm、273 nm。2,4-二硝基氯苯和对硝基氯苯的回收率分别为92.0%～108.4%、88.8%～102.1%,相对标准偏差RSD分别为0.76%(n=6)和1.36%(n=6),检出限均为0.002 mg/kg。该方法快速、简便、准确、稳定、灵敏度高,适合用于固体废物中2,4-二硝基氯苯与对硝基氯苯的含量测定。     

改变检测波长高效液相色谱法测定喜树碱和羟基喜树碱的含量

建立了改变检测波长测定喜树种子中喜树碱和 10 羟基喜树碱的高效液相色谱法。使用TechspheseODSC18(4.6mm× 2 5cm ,5 μm)色谱柱 ,以水∶乙腈 =3∶7(V/V)为流动相 ,流速为 1.0mL/min ,2 5℃下检测。检测波长 :0～ 8min时为 2 6 6nm ,8～ 2 0min时为 2 5 4nm。结果表明 :喜树碱的平均回收率为 10 0 .92 % ,RSD值 1.4 0 % ;羟基喜树碱的平均回收率为 10 0 .0 9% ,RSD值 1.34%。此方法简单、可靠。     

QuEChERS-超高效液相色谱-串联质谱法测定血液中4种乌头类生物碱

移取1.00mL血液样品,加入2mL乙腈和50mg氯化钠,振荡10min后,在-4℃下以8 000r·min~(-1)转速离心10min,取上清液,加入15mg N-丙基乙二胺和25mg十八烷基硅烷,振荡5min,重复上述离心操作,取上清液,过0.22μm有机微孔膜,采用超高效液相色谱-串联质谱法测定滤液中次乌头碱、新乌头碱、乌头碱和滇乌头碱等4种乌头类生物碱的含量。以Agilent ZORBAX Eclipse Plus C_(18)色谱柱为固定相,以不同体积比的0.1%(质量分数)氨水和甲醇的混合液为流动相进行梯度洗脱,串联质谱分析中采用电喷雾正离子源和多反应监测模式。4种乌头类生物碱的质量浓度在一定范围内与其对应的峰面积呈线性关系,方法的检出限(3S/N)为0.010～0.035μg·L~(-1)。以空白样品为基体进行加标回收试验,所得回收率为96.3%～109%,回收量的日内相对标准偏差(n=6)为2.3%～4.2%,日间相对标准偏差(n=6)为0.70%～6.7%。     

动物源食品中6种甲状腺抑制剂残留的超高效液相色谱-串联质谱法检测

建立了动物源食品中2-硫脲嘧啶、6-甲基-2-硫脲嘧啶、6-丙基-2-硫脲嘧啶、6-苯基-2-硫脲嘧啶、2-巯基-1-甲基咪唑和2-巯基苯并咪唑6种甲状腺抑制剂残留检测的超高效液相色谱-串联质谱(UPLC-MS/MS)分析方法。以BEHC18柱(50mm×2.1mm,1.7μm)为色谱柱,乙腈(含0.1%甲酸)-0.1%甲酸水溶液为流动相,梯度洗脱;柱温为30℃,流速为0.3mL/min,进样量为10μL。质谱条件为:电喷雾离子源(ESI+),多反应监测(MRM)模式。结果表明:6种药物在5～500μg/L质量浓度范围内呈良好的线性关系,相关系数r2均大于0.996;方法检出限为2μg/kg,定量下限为5μg/kg;在10、25、100μg/kg3个添加水平下,方法的平均回收率为60%～107%,批内、批间RSD均小于16%。     

以甲基橙为显色剂萃取光度法测定喜树中总生物碱

为测定喜树中总生物碱含量,取样品的提取液100μL,在pH 5的柠檬酸-磷酸盐缓冲介质中与甲基橙反应.反应混合液在25℃保持5 min后,用三氯甲烷10 mL进行萃取将生物碱转入有机相中,用光度法于366 mm波长处以三氯甲烷溶剂作参比测定其吸光度.用纯喜树碱作对照品,测得的吸光度与喜树碱质量浓度在6.5～104.0 mg·L-1范围内呈线性关系.取来自同一批的样品5份,按所提出的方法测定其总生物碱量,测定值的相对标准偏差为1.62%.在一已知样品的基础上,用标准加入法进行了回收试验,测得平均回收率为98.7%.     

柱前衍生-反相高效液相色谱法测定人血白蛋白中辛酸钠含量

建立了柱前衍生-反相高效液相色谱法测定人血白蛋白中辛酸钠含量的方法。用正己烷萃取人血白蛋白中的辛酸钠,与ω-溴苯乙酮和18-冠-6醚在50℃反应30min,然后用甲醇-水(75∶25,V/V)于Nova-ParkC18柱(150mm×3.9mm,4μm)上分离,在262nm检测衍生物,流速为1.0mL/min,庚酸为内标。辛酸和庚酸的萃取率可分别达到98.2%和97.9%,RSD小于0.9%。方法的线性范围为9.00×10-4～1.44×10-2mol/L(r=0.9995),平均加样回收率为99.7%,RSD≤0.9%。本方法准确、重现性好,可用于人血白蛋白中辛酸钠含量的测定。     

UPLC法同时测定注射用丹参(冻干)中6种酚酸的含量

建立同时测定注射用丹参(冻干)中丹参素钠、原儿茶酸、原儿茶醛、异阿魏酸、丹酚酸G和迷迭香酸6种酚酸类成分含量的UPLC法。采用ACQUITY UPLCHSS T3(2.1 mm×100 mm,1.8μm)色谱柱,流动相为0.1%甲酸(A)-乙腈(B)系统梯度洗脱(0 min,100%A;0~5 min,0%B~8%B;5~10 min,8%B~20 B;10~20 min,20%B~45%B;20~24 min,45%B~100%B;24~25 min,100%B~100%A;25~30 min,100%A),流速0.3 mL/min,柱温30℃,检测波长254 nm。结果显示6种酚酸类成分在一定范围内(丹参素钠101.5~1624.0μg/mL、原儿茶酸0.846~13.540μg/mL、原儿茶醛82.60~1321.60μg/mL、异阿魏酸5.01~80.16μg/mL、丹酚酸G 8.97~143.52μg/mL、迷迭香酸8.67~138.72μg/mL)线性关系良好(r=0.9990~0.9998),平均加样回收率在95.1%~102.9%范围内,RSD均小于3.0%。该法经验证准确可靠,可用于该制剂中6种酚酸的含量测定,为其多成分质量控制提供了科学依据。     

热解吸–气质联用法测定纺织品中有机挥发物的含量

采用热解吸–气质联用法测定纺织品中有机挥发物氯乙烯、1,3-丁二烯、甲苯、4-乙烯基环己烯、苯乙烯、4-苯基环己烯的含量。吹扫载气N2流量为30 m L/min,100℃吹扫顶空腔30 min,然后于290℃解吸吸附管10 min。色谱柱为DB–624柱,初始柱温35℃,保持5 min,以10℃/min升至240℃,保持10 min。检测上述6种有机物的线性范围分别为21.13~426.26,21.12~422.49,4.22~211.00,4.10~204.85,2.10~209.70,4.43~221.30μg/m L,线性相关系数均大于0.99。3个添加水平的平均回收率为88.8%~110.2%,测定结果的相对标准偏差为1.95%~6.59%(n=4)。该方法重现性好,测量结果准确,可作为纺织品质量控制的参考方法。     

阀切换技术在大气样品中六氟化硫快速分析中的应用

建立了双柱阀切换技术分析大气样品中的SF6含量的气相色谱-电子捕获检测器(GC-ECD)检测方法。采用规格为3.2 mm×1 m的5A分子筛(40~60目)柱为预柱,规格为3.2 mm×0.5 m的5A分子筛(60~80目)柱为分析柱。在所用实验条件下,平均峰高响应为1.08×10-14 mL/μV,SF6单位体积进样量的色谱峰高的相对标准偏差为2.2%,SF6的最低检测限为6.03×10-13 mL(3倍基线噪声)。采用该方法分析大气中SF6的含量,样品分析时间为1.2 min，于12 min内完成11个空气样品的分析,SF6含量的相对标准偏差2.1%。     

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.     

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^-。     

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.     

恶臭嗅辨实验室建设探讨

针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。     

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.     

解决能源问题的新途径--光解水制氢的研究

面对日益枯竭的能源危机,氢能是一种洁净、最有前景的替代能源。目前在各种制氢的方法中光催化分解水制氢的研究最多,光解水过程中催化剂最关键,本文对利用太阳能光解水的途径、提高光催化反应效率以及光催化剂的开发研究进行了综述。     

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.     

黄酮化合物的合成研究进展

黄酮化合物是一类具有多种生物活性的天然产物,其经典的合成方法主要为查耳酮路线和β-丙二酮路线.近年来出现了许多新技术、新方法.本文介绍了2'-羟基查尔酮的氧化关环法、黄烷酮氧化法、改进的Baker-Venkataraman法及其他合成黄酮化合物的方法.     

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.