柚子果皮油挥发性成分的气相色谱-质谱分析

采用溶剂萃取提取柚子果皮的精油,经气相色谱和质谱联机分析,同时依据各成分的保留指数,鉴定出71种挥发性物质,其中有21种碳氢化合物,50种含氧化合物。在碳氢化合物中以柠烯、γ－萜品烯为主要成分;而在含氧化合物中主要是沉香醇、α－萜品醇、百里酚以及一些脂肪族醛。     

萃取淫羊藿挥发油的实验与分析

报道了用正交实验法研究超临界萃取淫羊藿挥发性成分的条件;结果显示最佳萃取条件为萃取压力30 MPa,萃取温度40℃,萃取时间1 h。按对结果影响大小依次排列为:萃取压力→萃取温度→萃取时间,在最佳条件下萃取挥发油,收率为2.7%;并用气相色谱-质谱联用技术分析了淫羊藿挥发油的化学成分,从中确认出43种化学成分,用峰面积归一化法通过化学工作站数据处理系统得出各化学成分在挥发油中的质量分数;其中主要成分为薄荷醇、1,2-二甲氧基-4-(2-丙烯基)-苯、5-(1-丙烯基)-1,3-苯并间二氧杂环戊烯、3,5-二甲氧基-甲苯、冰片、十五(碳)烷、1,2,3-三甲氧基-5-甲苯、外-葑醇、2,6,6-三甲基-2,4-环庚二烯-1-酮、2-莰酮等。     

用极微弱化学发光法评价萜类化合物的稳定性

在60℃氧气中,用极微弱化学发光法测定单萜类化合物的化学发光强度,通过化学发光强度评价了单萜类化合物对氧气的稳定性。萜烯类化合物的稳定顺序为:γ-松油烯<莰烯<异松油烯=α-松油烯<β-蒎烯<β-月桂烯<α-蒎烯=柠檬烯。萜醇类化合物的稳定顺序为:桃金娘醇<紫苏醇<α-松油醇<龙脑=香茅醇=薄荷醇。萜醛类化合物的稳定顺序为:桃金娘醛<紫苏醛。具有同样骨骼,不同官能团的单萜类化合物稳定顺序为:萜醛<萜醇<萜烯。     

超临界流体萃取-GC-MS分析西黄丸中挥发性成分

建立西黄丸中挥发油成分乙酸辛酯的含量测定方法,为西黄丸的质控标准提供依据。方法:超临界CO2萃取西黄丸中挥发油成分,采用气相色谱法测定乙酸辛酯含量;研究压力、温度、时间和粒度因素对挥发油得率与乙酸辛酯含量的影响,并进行了化学计量学分析。采用GC-MS分析了适宜条件的挥发油的成分。综合考虑挥发油得率和乙酸辛酯含量双指标,确定的西黄丸挥发油萃取条件为:粉碎粒度为80目,萃取压力为25 MPa,温度为40℃,时间为2 h。在此条件下,挥发油得率达到7.76%,乙酸辛酯含量达到0.72 mg·g^-1。通过指纹图谱、主成分分析(PCA)、正交偏最小二乘判别分析(OPLS-DA)化学计量学分析可知,不同萃取条件对所提取的挥发油物质组分及其含量没有显著性差异。GC-MS鉴定出的主要成分有(1S-endo)-2-甲基-3-亚甲基-2-(4-甲基-3--3-戊烯基)-二环[2.2.1庚烷、10α-羟基日本刺参萜、(±)-麝香酮、4-亚甲基-2,8,8-三甲基-2-乙烯基-双环[5.2.0]壬烷和2-甲基-4-(2,6,6-三甲基-1-环己烯-1-基)丁醛。结论:西黄丸挥发油成分适宜萃取条件,及建立的乙酸辛酯含量测定方法准确、可靠,为有效控制西黄丸质量,完善其质量标准及进一步的药效成分研究提供了科学依据。     

气相色谱-质谱技术分析红松松塔挥发性成分

采用水蒸气蒸馏法，对红松松塔挥发性成分进行提取和研究，最佳蒸馏时间5.5h，挥发油提取率1.28％。利用气相色谱-质谱联用技术对提取的挥发油成分进行分析，共鉴定出32种化学成分，主要为单萜和倍半萜类化合物，其中相对含量较高的有α-蒎烯（44．258％）、D-柠檬烯（23．426％）、β-蒎烯（8.674％）、有石竹烯（3.462％）、β-月桂烯（3.018％）等。研究结果表明红松松塔挥发油中富含α-蒎烯、D-柠檬烯、石竹烯等多种具有药理活性的成分。因此，红松松塔是一种具有较好前景的天然药用资源。     

头花杜鹃挥发油化学成分的研究

应用分馏、硅胶柱层析和含硝酸银的氧化铝柱层析,从头花杜鹃发油中分得24个化合物,经紫外光谱、红外光谱、核磁共振谱、质谱及气相色谱的测定,其中20个化合物被鉴定为:d-α-蒎烯(1),dl-JB-蒎烯(2),香叶烯(3),顺式-α-罗勒烯(4),β-古芸烯(5),δ-杜松烯(6),γ-芹子烯(7),α-芹子烯(8),χ-芹子烯(9),反式β-法呢烯(10),α-葎草烯(11),(一)-16α-贝壳杉醇(12),醋酸冰片酯(13),α-萜品醇-4(14),α-萜品醇(15),反式松油醇(16),里哪醇(17),前异水昌蒲二醇(18),环氧薇草烯-Ⅱ(19)和桧脑(20). 化合物4,5,11～17和19是首次从杜鹃属植物中分到.     

气相色谱-质谱法分析蘘荷花穗挥发油化学成分

采用水蒸气蒸馏法提取黔产蘘荷花穗挥发油，并用气相色谱-质谱对其成分进行定性分析和峰面积相对含量的测定．共鉴定出45个化学成分，占挥发油总量的95．89％．主要成分为β-水芹烯(34．96％)、α-律草烯(13．09％)、β-榄香烯(7．31％)、β-蒎烯(6．50％)、α-水芹烯(6．07％)、α-蒎烯(3．87％)、β-石竹烯(3．18％)等。     

气相色谱-质谱法测定姜黄挥发油化学成分

采用水蒸气蒸馏法提取姜黄挥发油,用气相色谱－质谱联用技术分离和鉴定姜黄挥发油的化学成分。经计算机ＮＢＳ谱库检索,发现姜黄挥发油中至少有１５个峰,鉴定出α－姜黄烯、α－姜烯、桉叶油素和球姜酮等１５种组分;另外还有１－（３－环戊基醛）－２,４－二甲基苯、β－倍半水芹烯、大根香叶酮、大根香叶烷、顺双环［３,３,１］酮－２－烯－９－醇等成分。姜黄挥发油中主要成分为α－姜黄烯。     

合成芳樟醇的研究进展

本文综述了合成芳樟醇的路线及关键反应的研究进展．包括乙炔－丙酮法、异戊二烯法、β－蒎烯法与α－蒎烯法．重点综述α－蒎烯法，即：蒎烯氢化、蒎烷氧化、蒎烷氢过氧化物还原与蒎烷醇的热解。     

新型驱蚊产品中35种挥发性致敏芳香剂的筛查方法及挥发规律研究

基于顶空/气相色谱－串联质谱（HS/GC－MS/MS）建立了驱蚊贴、驱蚊扣、驱蚊手环等新型驱蚊产品中35种挥发性致敏芳香剂的分析方法。35种物质经中等极性色谱柱Agilent DB－17MS分离,采用电子轰击源（EI源）通过多反应监测（MRM）模式进行检测。考察了37个新型驱蚊样品在顶空温度分别为40 ℃和100 ℃时的筛查结果,40 ℃顶空条件下筛查出α-蒎烯、β-蒎烯和D-柠檬烯等14种致敏芳香剂,此外,100 ℃时还检出香叶醇、香芹酮等其它12种致敏芳香剂。以儿童用驱蚊贴和驱蚊扣为例,比较了不同顶空温度对各目标化合物响应强度的影响,结果表明,40 ℃时α-蒎烯、β-蒎烯和D-柠檬烯等8种致敏芳香剂的响应强度小于100 ℃时。对37个样品在40 ℃平衡温度下的半定量分析表明,α-蒎烯、β-蒎烯、D-柠檬烯等9种致敏芳香剂的检出率最高,其中α-蒎烯和D-柠檬烯的最高响应强度大于106。选择驱蚊贴和驱蚊扣进一步考察了α-蒎烯、β-蒎烯、D-柠檬烯、薄荷醇和樟脑5种致敏芳香剂在40 ℃下放置不同时间的挥发规律,发现α-蒎烯、β-蒎烯和D-柠檬烯放置12 h的响应强度为初始的20% ~ 21%,薄荷醇和樟脑放置72 h后响应强度仍为初始的40%以上。该研究可为后续开展新型驱蚊产品中化学物质的含量测定和风险评估提供技术参考。     

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.     

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.     

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。     

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。     

微量钙的测定方法研究进展

介绍了1995-2006年期间测定微量和痕量钙的方法,如电感耦合等离子体-原子发射光谱法、原子吸收光谱法以及离子色谱法等的工作原理和特点,并说明了其测定微量钙的应用领域。并对微量钙的测定技术进行了展望(引用文献55篇)。     

Stages of thermal decomposition of sodium oxo-salts of sulphur

Thermal behaviour of sodium oxo-salts of sulphur: Na₂SO₄, Na₂S₂O₇, Na₂S₂O₆, Na₂SO₃, Na₂S₂O₅, Na₂S₂O₄, Na₂S₂O₃, Na₂S₃O₆ and of sulphides Na₂S and Na₂S₂ was studied on heating up to 1000°C. The experiments were performed with anhydrous compounds obtained from commercial products by recrystallisation and dehydration. The stage mechanisms of decomposition of anionic sub-lattices of the salts have been proposed basing on the Górski’s morphological classification of simple species. The thermal stability and the stage decomposition mechanisms were correlated with the structure and the potential chemical properties of the salt anions. The thermal decomposition processes were studied by means of thermal analysis, and the decomposition products were identified by means of X-ray phase analysis.