气相色谱-质谱联用法分析烟丝中有机酸成分

采用三氟化硼和甲醇对西湖香烟烟丝样品进行衍生化反应，以二氯甲烷为萃取液，得到烟丝样品有机酸甲酯成分，在GC/MX气相色谱/质谱联用仪上定性和定量分析，共鉴定出有机酸41种，主要成分依次为苹果酸、柠檬酸、亚麻酸。实验表明分析方法简便、快速，结果令人满意。     

近红外光谱技术在快速检验制丝过程中烟丝质量均一性上的应用北大核心CSCD

采用近红外光谱技术结合主成分分析-马氏距离法研究了卷烟制丝工艺过程中掺配、加香、贮丝及喂丝等4个工序段中烟丝样品的质量均一性。用主成分分析法提取近红外光谱所包含的特征信息,较全面地反映制丝过程4个不同取样点样本的离散程度,马氏距离可反映制丝过程中烟丝质量的波动情况。此外,采用成品烟丝的模型预测了取样点D处烟丝样品中6种化学成分(总植物碱、总糖、还原糖、总氮、钾和氯)的含量,使不同批次的烟丝样品中化学成分的差异控制在合理范围,降低批次间卷烟产品化学成分含量的波动,能有效稳定品牌香烟的特征风格。     

近红外光谱技术在快速检验制丝过程中烟丝质量均一性上的应用

采用近红外光谱技术结合主成分分析-马氏距离法研究了卷烟制丝工艺过程中掺配、加香、贮丝及喂丝等4个工序段中烟丝样品的质量均一性。用主成分分析法提取近红外光谱所包含的特征信息,较全面地反映制丝过程4个不同取样点样本的离散程度,马氏距离可反映制丝过程中烟丝质量的波动情况。此外,采用成品烟丝的模型预测了取样点D处烟丝样品中6种化学成分(总植物碱、总糖、还原糖、总氮、钾和氯)的含量,使不同批次的烟丝样品中化学成分的差异控制在合理范围,降低批次间卷烟产品化学成分含量的波动,能有效稳定品牌香烟的特征风格。     

示波极谱法烟丝中尼古丁含量测定及电极反应机理

研究了用示波极谱法直接测定烟丝中的尼古丁含量的新方法.在0.2mol/L草酸底液中(pH=4.0),于-1.22V处得到尼古丁的灵敏还原峰,峰电流与尼古丁浓度在1.5～31.5mg/L范围内呈良好的线性关系,检测下限达0.37mg/L.该方法用于烟丝中尼古丁含量的测定,简单快速,测定回收率在91%左右.     

硅烷化GC-MS指纹图谱在卷烟品牌分析中的应用

采用硅烷化衍生化法结合气相色谱-质谱(GC-MS)法对卷烟烟丝中的主要化学成分进行检测,获得了21个卷烟样品的烟丝硅烷化GC-MS指纹图谱数据,并应用聚类分析和主成分分析法对烟丝硅烷化GC-MS指纹图谱数据进行综合评价。结果表明,该方法可用于不同品牌卷烟的比较和区分,硅烷化成分的含量分布特征能反映不同品牌卷烟的特性,可为卷烟品牌的风格表征、品质维护和真伪鉴别提供参考。     

烟草抽取物的GC-MS分析

烟叶广为世界各国种植.烟叶产地不同,品质差异甚大;成品烟中调配香精的不同,也在很大程度上影响烟民的品味.因此,有必要研究不同品种烟叶中化学成分差异及调配香精的组成.我们对成品烟丝和调配前的烟丝共50种样品的二氯甲烷抽取物进行了GC-MS分析和部分成分的标准品验证.结果发现样品中化学成分的种类和含量都有较大的差别,抽取物中鉴定出成分最多的有50余种,包括呋喃甲醛、苯乙醛、苯乙醇、尼古丁、茄酮、大麻酮、香叶基丙酮、金合欢基丙酮、忻植二烯、叶绿醇等重要香精和烟中固有成分,为研究不同烟种成分提供了大量参考数据,同时也为调配香精提供可靠依据.     

微波消解ICP-AES法测定螺蛳肉中镉

镉是一种对人体有害的微量元素 ,即使存在于香烟中的微量镉经呼吸道进入人体 ,蓄积到一定程度也会危害健康[1] ,国家标准明确规定了食品中镉的限量[2 ] ,对食品中镉的测定方法有石墨炉原子吸收光谱法、火焰原子吸收光谱法、比色法[3] ,香烟中镉的测定已报道的有阳极溶出伏安法和微分电位溶出法[4 ,5] 。这些方法普遍存在样品处理时间长 ,试剂用量大 ,有些还使用对环境有污染的试剂。微波消解作为样品分析的新技术 ,由于消化样品能力强、速度快、消耗化学试剂少 ,金属元素不易挥发损失 ,污染小 ,空白值低等优势 ,已被广泛应用于化学分析前处…     

傅里叶变换红外光谱体表无创探测乳腺肿瘤

利用傅里叶变换红外(FTIR)光谱仪联合衰减全反射(ATR)探头的中红外光导纤维对46名健康志愿者及113名乳腺肿物患者的体表皮肤进行无创红外光谱测定, 并从分子水平比较、分析了正常乳腺和有肿物乳腺体表皮肤的红外光谱特征. 结果表明, 健康志愿者乳房皮肤8个FTIR光谱测定部位的图谱趋于一致; 正常乳腺体表与有肿瘤乳腺体表的吸收峰差异明显, 而1080 cm^-1处核酸相关吸收峰的变化对鉴别肿瘤的良、 恶性有重要意义.     

CO2超临界提取和水蒸汽蒸馏提取桂皮中化学成分的分析

采用气相色谱-质谱联用技术对桂皮的CO2超临界提取物和水蒸汽蒸馏提取物进行了分析.分别分离出了36个峰和32个峰,用峰面积归一化法定量测定了组分的相对含量并进行了对比,其CO2超临界提取物较水蒸汽蒸馏法提取物多4个峰,其含量也有一定的差别.比较了两种提取方法的差异.     

痕量镉离子在原位铋修饰掺硼金刚石电极上的传感分析

以原位铋修饰掺硼金刚石电极为工作电极,利用方波脉冲阳极溶出伏安法对重金属镉离子进行检测.考察了扫描方式、铋离子浓度、电极硼掺杂浓度、支持电解液p H值、富集电位、脉冲参数和富集时间等因素对镉溶出峰电流的影响并进行了优化.结果表明,原位铋修饰能有效提高检测的灵敏度,镉离子浓度与溶出峰电流值在1~10μg/L范围内呈线性关系,相关系数为0.9979,检出限为0.15μg/L.干扰实验结果表明,相邻溶出电位干扰离子铅和锌对镉的检测影响相对较小,而铜有较大干扰.实际水样测试结果表明,回收率在96%~107%之间.     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

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.     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

物质分配系数的测定实验改进

实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。     

Calculation of enthalpies of hydrogenation of hydrocarbons

Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.     

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。