超声辅助液液萃取法提取烟用香精成分的研究

采用超声辅助液液萃取法(ULLE)提取某品牌烟用香精成分,GC-MS对其进行分析,研究了不同萃取剂、萃取时间和萃取温度对分析结果的影响,初步确定了最佳条件为:以二氯甲烷为萃取剂,饱和NaCl溶液作水相,室温下超声萃取5 min.又分别与同时蒸馏萃取法(SDE)和传统的液液萃取法(LLE)作以比较,对ULLE法和SDE法鉴定出的化学成分、重现性和定量值进行了对比.结果表明:超声辅助液液萃取具有操作简便、快速、节能、萃取效率高、重现性好等特点,适合于烟用香精成分的提取.     

气相色谱-质谱联用法测定烟用香精成分——烟草用香精前处理方法比较

采用同时蒸馏萃取(SDE)、超声辅助液液萃取(ULLE)和固相微萃取(SPME)3种前处理方法提取HMT-3烟用香精成分,用气相色谱-质谱联用法(GC-MS)进行分析.对3种萃取方法鉴定出的组分作出比较,考察了方法的各自特点.选取了15种烟用香精为代表,分别采用3种萃取方法对不同类型的烟用香精进行提取.结果表明:ULLE操作简便、快速、节能、萃取效率高;SDE法和ULLE法的重现性明显好于SPME法,适合于香精的定量分析,而SPME有较高的灵敏度,更适合香精的定性分析.根据定性和定量的需要、方法的适用性和香精的物理状态,应选取不同的提取方法,从而能够快速、准确地获得样品信息.     

水产品挥发性成分研究进展

近年来伴随着同时蒸馏萃取(SDE)、固相微萃取(SPME)、固相萃取整体补集剂(Mono Trap)等提取技术及色谱(GC)、质谱(MS)、飞行时间质谱(TOFMS)、电子鼻等分析鉴定技术在水产品挥发性成分研究中的应用,水产品挥发性成分的研究已成为水产品研究中的热点。对近几年来国内外在水产品挥发性成分方面的研究情况,包括研究内容、研究方法及研究进展进行综述,有助于水产品挥发性成分的深入研究。     

SDE与SPME在分析水体中有机氯农药的对比

就水体中有机氯农药的分析对比了一滴溶剂萃取(SDE)与固相微萃取(SPME)两种预处理技术，并对影响SDE的因数(萃取溶剂、萃取时间、萃取温度和搅拌速度)进行了条件优化。结果表明，优化后的SDE不仅在相同的浓度范围内有更好的线性关系(相关系数为0．9976～0．9999)，且增宽了β-666和P，P‘-DDT的线性范围，降低了β-666、γ-666、δ-666和P，P‘-DDT的检出限，用SDE-GC-μECD检测水体中有机氯农药残留方法是简单快速、经济廉价、准确可行。     

固相微萃取活性炭涂层萃取头对水中有机物的定性分析

对自制的固相微萃取（SPME）活性炭（AC）涂层萃取头进行了评价。该涂层富集能力强,对苯系物（BTEX）的富集率达到14．5～19．2倍;热稳定性好,最高使用温度可达290℃;使用寿命长,260℃解吸条件下可反复使用140次以上。其与聚二甲基硅氧烷（PDMS）涂层相比,尽管萃取量略小,但其具有更高精密度和准确度,而且其萃取和解吸平衡时间减少为聚二甲基硅氧烷（PDMS）涂层的一半以上。应用AC涂层SPME法和液-液萃取（LLE）法对松花江水进行了气相色谱-质谱（GC-MS）定性比较分析。两种方法分别检测到50种（主要是挥发和半挥发性的弱极性和非极性）和44种（主要是挥发性差、与正己烷相容性较强）化合物。     

葫芦脲用作固相微萃取涂层新材料

本文对葫芦脲(CB)作为一种新型固相微萃取(SPME)涂层材料进行了研究并用于中药白豆蔻的气相色谱分析测定.本文采用的CB SPME涂层制备方法简便、快速,并具有良好的热稳定性和重复性.CB[6]SPME萃取得到的主要成分与水蒸气蒸馏（SD）法基本一致,并且CB[6]SPME对色谱后流出的目标成分的相对峰面积比明显高于SD法和商品SPME萃取材料PDMS/CAR和PDMS/DVB,这可能是由于葫芦脲的特殊分子结构及其与组分分子间选择性作用所致.葫芦脲作为一种新型SPME涂层材料具有很大的研究潜力和应用前景.     

低温冷冻及分散固相萃取净化-超高效液相色谱-串联质谱法测定植物油中104种农药残留

建立了适用于植物油中104种农药残留的检测方法。通过液液萃取(LLE)提取目标化合物,再借助离心、冷冻和分散固相萃取(D-SPE)净化手段,依托超高效液相色谱-串联质谱测定。以回收率和共提取物为衡量指标,着重优化了6种提取方式、不同冷冻时间及PSA(primary secondary amine)、GCB(graphite carbon black)和C18这3种不同固相萃取填料不同组合的效果。在0.01、0.02和0.05 mg/kg水平的平均添加回收率为55%~121%, RSD为0.47%~19.2%, 80%的目标物的定量限可达到1 μg/kg,低于我国相关标准限量,能够满足多种农药残留同时分析的要求。该方法步骤简便、可靠、稳定,可应用于进口植物油中多种农药残留的快速检测与确证的日常检测工作中,具有一定的推广价值。     

微波蒸馏-固相微萃取-气相色谱-质谱-嗅觉检测器联用分析鳙鱼鱼肉中的挥发性成分

用微波蒸馏(MD)-固相微萃取装置(SPME)提取鳙鱼鱼肉中的挥发性成分,利用气相色谱-质谱联用仪(GC-MS)对气味化合物成分进行了定性分析,同时利用嗅觉检测器鉴别了部分挥发性物质的气味特征。实验中优化了MD的操作条件(加热功率、加热时间及载气流速等)、SPME参数(萃取头种类、萃取温度、萃取时间、无机盐离子浓度及搅拌速率等)。通过NIST 02质谱数据库检索共定性确定出鳙鱼鱼肉挥发性成分中的53种化合物,其中主要为 C6~C9 的羰基化合物和挥发性醇类。经过嗅觉检测器分析,这些成分分别具有青草味、鱼腥味、泥土味等气味特征,其协同作用构成了鳙鱼鱼肉特殊的鱼腥味、泥腥味。该方法可用于水产品中挥发性成分的分析,并可为不良风味化合物的定量研究提供参考。     

气相色谱火焰光度法测定水体中9种有机磷酸酯阻燃剂

建立了水体中9种有机磷酸酯阻燃剂(OPFRs)的液液萃取(LLE)/气相色谱-火焰光度(GC-FPD)测定方法。对比研究了液液萃取、固相萃取条件和仪器测定条件。最终选择液液萃取作为样品的提取方法,以二氯甲烷为提取溶剂;有机磷专用柱Rtx-OPPesticides 2作为分析柱,15 min内可实现待测组分的良好分离。在优化条件下,9种OPFRs在1.0~500 ng/m L范围内呈良好的线性关系(r2≥0.998),方法检出限为1.0~2.0 ng/L。在5,100,300 ng/L加标水平下,9种OPFRs空白水样的加标回收率为75.9%~111%;相对标准偏差(RSD)为3.3%~15%。该方法应用于6个实际湖泊地表水样品的检测,OPFRs的检出率为100%,其组分检出总浓度为408~1 532 ng/L,可见湖泊地表水中存在明显的OPFRs污染。     

固相微萃取-GC-MS法和静态顶空-GC-MS法同时测定库尔勒香梨的香气成分

采用固相微萃取(SPME)和静态顶空(SHS)两种方法采集新疆库尔勒香梨的挥发性成分,并对固相微萃取的萃取条件进行了优化,结合气相色谱-质谱联用进行分析鉴定,对总离子流色谱的峰面积进行归一化定量。结果表明,静态顶空(SHS)和固相微萃取(SPME)分别得到60种、85种挥发性成分,将两种方法结合起来能够较完整地描述库尔勒香梨的香气成分,α-金合欢烯、己酸乙酯、乙酸己酯、丁酸乙酯、乙酸正丁酯、十五烷是两种萃取方式下共同测得的主要香气成分,是对库尔勒香梨呈香贡献的主要物质。     

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。     

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.     

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.     

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.     

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。