Differentiation of strawberry varieties through purge-and-trap HRGC-MS,HRGC-FTIR and principal component analysis

The aroma composition of three different Fragaria anannassa cul-tivars Selva, Chandler, and Osso Grande) is studied by purge-and-trap HRGC and the components identified by MRGC-MS and HRGC-FTIR. The chromatographic aroma profiles from four different maturation stages in each variety are compared and the similarities accessed by principal component analysis (PCA). The contents in n-hexanal and hex-2(Z)-enal are characteristic features of the green stage in the three varieties where the content differences in methyl, ethyl, and butyl acetates act as typifying variables among varieties. Ethyl acetate acts as an important differentiation variable for the Selva variety. In the mature stage, the three cultivars may be distinguished from each other through their relative contents of methyl and ethyl 2-methylbutyrate (Selva), methyl 2-methyl-butyrate, methyl butyrate (Chandler), methyl and ethyl butyrates, and methyl caproate (Osso Grande).     

艾蒿柱层析馏分成分分析

将甲苯浸泡获得的艾蒿提取物置于硅土层析柱上,再用乙酸乙酯淋洗获得一个柱层析馏分。用气相色谱对该馏分进行分离,用质谱法和红外光谱法对分离组分进行了结构鉴定。共鉴定出20个纽分,其中倍半萜3个,单萜6个,在这9个萜类组分中,有3个是首次报道。同样,用液相色谱-质谱联用仪(LC—DAD-MSD)对该馏分进行了分析鉴定,结果显示这些组分中可能存在大量的萜类物质。     

气相-红外光谱联用技术鉴定对羟基联苯加氢产物的异构体

对羟基联苯的选择性催化加氢反应是一个平行连串复杂反应,由于反应物的两个苯环加氢的难易程度不同,使得产物中含有两个不同的苯环分别加氢或者全部加氢而生成多个异构体,用通常的分析方法难于对异构体进行区分鉴定。使用气相-红外光谱联用分析手段,通过对苯环的对位和单取代位置的波数特征进行分析,可以鉴定出加氢反应的主产物是对环己基苯酚,副产物是由对环己基环己醇和对苯基环己醇的异构体组成。气-质联用、熔点测定、核磁共振等辅助分析,进一步验证了气相-红外光谱联用分析结果的准确性,表明气-红联用技术是一个快速准确分析具有特征官能团的有机化合物异构体的现代仪器方法。     

Characterization of citrus and kiwi flavors and their degradation processes by combination of GC/FTIR and GC/MS

Flavor samples are complex mixtures with components of sometimes very similar chemical behavior (e.g. isomeres). As an approach towards their characterization an integrated analytical method on the basis of capillary gas-chromatography (HRGC) was applied consisting of two molecular specific techniques for component-identification in unknown samples: GC-FTIRS (GC-Fourier transform infrared spectrometry) and GC-MS (GC-mass spectrometry).In addition GC-retention indices-from simultaneous GC on two columns (nonpolar/polar) —were stored in a database for routine retrieval and quantitative monitoring. To correlate this information with sensory perception sniffing chromatograms were generated with the human nose as a high performance detector.Because of the high information contents of GC-FTIR spectra in this field a small but specific vapor-phase-FTIR flavor library was accumulated, which dramatically improved the fast identification power of GC-FTIRS alone.     

气相色谱-傅里叶变换红外光谱联用法测定白酒中3种醛类香料组分

建立了气相色谱–红外光谱联用法测定白酒中乙醛、戊醛、异戊醛3种醛类挥发性香料成分的方法。白酒样品直接进样分析,在10～10000 mg/L范围内,3种醛类的色谱峰面积与质量浓度线性相关,相关系数大于0.998,方法的检出限为10 mg/L,加标回收率大于90%。利用各个组分的特征红外谱图,提高了分析定性和定量的准确性,特别是提高了对同分异构体的区分能力。     

GC－FTIR联用技术测定水中有机污染物

采用毛细管气相色谱－博里叶变换红外光谱（ＧＣ－ＦＴＩＲ）技术对工业废水中的有机污染物进行了鉴定，井用气相色谱－质谱（ＧＣ－ＭＳ）进行了对照。在分离出的２５个组分中，ＧＣ－ＦＴＩＲ发挥了能给出官能团信息和区别同分异构体的长处，而ＧＣ－ＭＳ则发挥了灵敏度高、能提供分子量信息和区别同系物的特点。两种技术的结合为环境有机污染物的检测提供了有力的手段     

Investigation of high sensitivity GC-FTIR as an analytical tool for structural identification

As part of a detailed investigation into the application of GC-FTIR in industrial and environmental analysis, representative sets of samples have been analyzed in parallel using commercial high-sensitivity instruments. Two of the instruments utilize low temperature storage of the GC eluate to extend the time available for FTIR analysis, yielding greater sensitivity than that possible by conventional ‘light-pipe’ GC-FTIR. In certain circumstances, instruments using both types of sample storage give rise to spectra exhibiting features characteristic of the interface used. Chromatographic resolution was found not to be significantly degraded by use of either sample storage interface. Particular advantages were found in having parallel flame ionization detection and mass spectrometry; this enabled the location of smaller components and gave greater certainty of identification.     

The use ofN-alkylcarbamates in sample mapping of terpene alcohols

Carbamates (I) of terpene alcohols (e.g. menthol, borneol, citronellol, nerol, geraniol) were used to develop a method for characterization and mapping of alcohol components in complex essential oils using GC, GC-MS and GC-FTIR data and the almost quantitative reaction of the primary and secondary alcohols with isocyanates. The comparison of the data of original and derivatized samples is thus the basis for assignment of components to the primary, secondary and tertiary alcohol types (e.g. Sandalwood Oil, Rose Oil) in sample mapping procedure.The NH-deformation absorption band of (I) in vapour phase FTIR-spectroscopy at 1492–1494 cm^–1 proved to be of great use in the selective registration of derivatized alcohols in complex samples.     

GC－FTIR法分析天然小茴挥发油

利用ＧＣ－ＦＴＩＲ联用仪分析了小茴挥发油的化学组成。本法经调整气相色谱和红外光谱仪条件，分离效果好，灵敏度高，鉴定出了α－蒎烯、柠檬烯、１，８－桉树脑、葑酮、十五烷、爱草脑、葑基乙酸酯、甲氧苯基丙酮、反式茴香脑等九种物质。ＧＣ－ＦＴＩＲ法可作为分析挥发油组成的一种有效方法。     

生物质快速热裂解制取生物油试验研究

本文在快速热解试验装置中对片状的白松样品进行制取生物油的试验研究.考察了运行参数对热解产物分布的影响,重点研究了各个参数对热解气体和生物油组分的影响规律.结果表明,气体产物中主要以CO、CO2、H2和CH4为主,CO、H2和CH4的浓度随着温度升高而上升.生物油主要含有有机酸类、苯酚类和糖类等化合物.在同一载气流量下,随着辐射源温度的增加,大分子产物的产量逐渐减少,小分子产物的产量有所增加.在同一辐射源温度下,随着载气流量的减小,小分子产物的产量呈增加趋势.