鲤鱼体中鱼腥味物质的提取和鉴定

采用同时蒸馏萃取法提取鲤鱼鱼体中的挥发和半挥发性有机物，用GC／MS从提取物中分析鉴定出鱼腥味和疑是鱼腥味物质16种。包括醛、烯醛、酮和呋喃4类化合物。其中己醛、庚醛和2，4-二烯癸醛被确认为鱼腥味的化合物。研究发现，这些物质总量在鲤鱼体的鱼鳞、鱼鳃和鱼肉的分布呈现下降趋势，且其总量与鱼腥味强度之间具有可比较的对应关系。     

Analytical Aspects of Photoelectron Spectroscopy

Photoelectron spectroscopy is a new technique for experimentally measuring the binding energies of electrons in molecules. The basic principles of the method are outlined and simple guidelines for the interpretation of u.v.-excited photoelectron spectra are laid down. The analytical potential and possible development of the method are briefly surveyed.     

Sensory Perception of Non-Deuterated and Deuterated Organic Compounds

The chemical background of olfactory perception has been subject of intensive research, but no available model can fully explain the sense of smell. There are also inconsistent results on the role of the isotopology of molecules. In experiments with human subjects it was found that the isotope effect is weak with acetone and D₆-acetone. In contrast, clear differences were observed in the perception of octanoic acid and D₁₅-octanoic acid. Furthermore, a trained sniffer dog was initially able to distinguish between these isotopologues of octanoic acid. In chromatographic measurements, the respective deuterated molecule showed weaker interaction with a non-polar liquid phase. Quantum chemical calculations give evidence that deuterated octanoic acid binds more strongly to a model receptor than non-deuterated. In contrast, the binding of the non-deuterated molecule is stronger with acetone. The isotope effect is calculated in the framework of statistical mechanics. It results from a complicated interplay between various thermostatistical contributions to the non-covalent free binding energies and it turns out to be very molecule-specific. The vibrational terms including non-classical zero-point energies play about the same role as rotational/translational contributions and are larger than bond length effects for the differential isotope perception of odor for which general rules cannot be derived.     

高温毛细管气相色谱柱的制备及应用

研究了臭氧交联法制备毛细管气相色谱柱的方法,即用镀铝石英毛细管,涂渍ＳＥ３１,经臭氧交联,最高使用温度可达３６０℃。测试的结果表明其柱效高,吸附性小,热稳定性好,适用于烃类、醇类、多环芳烃及二硝基甲苯和三硝基甲苯的分离。     

硝基麝香香气化合物结构与香气性能关系的量子化学研究

ＡＭ１法计算结果表明，４个麝香香气合物的晶体结构与其最稳定结构符合得相当好。以稳定结构为基础研究总结其典型结构特征，用麝香香气分子共平面模型对其香气性能作了合理解释。     

脑功能磁共振成像在人类嗅觉研究中的应用

在人类的5种主要感觉中,嗅觉是最广泛、古老、直接和内在的感觉.这些特性使人们对人类嗅觉的研究异常艰难,以致于直到今天人们对嗅觉的功能仍不清楚,而对大脑的功能机制所知更少.与其他基于物理原理的方法一样,磁共振成像技术的广泛应用极大地推动了整个生命科学的发展.脑功能磁共振成像的优势(高分辨率、高对比度、无损性和无放射性等)为人们研究嗅觉高级中枢以及与嗅觉相关行为的脑机制等提供了强有力的技术手段.文章在简单介绍嗅觉知识的基础上,着重讨论了近十年来,脑功能磁共振成像技术在人类嗅觉研究中所取得的成果.     

Headspace Solid-Phase Microextraction/Gas Chromatography–Mass Spectrometry for the Determination of 2-Nonenal and Its Application to Body Odor Analysis

The odors and emanations released from the human body can provide important information about the health status of individuals and the presence or absence of diseases. Since these components often emanate from the body surface in very small quantities, a simple sampling and sensitive analytical method is required. In this study, we developed a non-invasive analytical method for the measurement of the body odor component 2-nonenal by headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry by selective ion monitoring. Using a StableFlex PDMS/DVB fiber, 2-nonenal was efficiently extracted and enriched by fiber exposition at 50 °C for 45 min and was separated within 10 min using a DB−1 capillary column. Body odor sample was easily collected by gauze wiping. The limit of detection of 2-nonenal collected in gauze was 22 pg (S/N = 3), and the linearity was obtained in the range of 1–50 ng with a correlation coefficient of 0.991. The method successfully analyzed 2-nonenal in skin emissions and secretions and was applied to the analysis of body odor changes in various lifestyles, including the use of cosmetics, food intake, cigarette smoking, and stress load.     

Characterization of Volatile Compounds of Rosa roxburghii Tratt by Gas Chromatography-Olfactometry,Quantitative Measurements,Odor Activity Value,and Aroma Intensity

Rosa roxburghii tratt (RRT), widely distributed in the southwest of China, is favored by consumers for its good taste and healthy functions. In this study, thirty-seven compounds of Rosa roxburghii Tratt (RRT) were identified and quantified by gas chromatography–olfactometry (G–O) and gas chromatography–mass spectrometry (GC–MS) analysis. Furthermore, ethyl 2-methylpropanoate, ethyl butanoate, ethyl 2-methylbutyrate, and ethyl hexanoate were present with much higher odor activity values (OAVs) than other compounds. The key notes were confirmed by omission tests. Possible interaction among key notes was investigated through odor intensity determination and sensory analysis. It showed fruity and woody notes had synergistic effects. Full factorial design was used to evaluate the notes contribution to the whole odor. One important finding is the major effect of order interactions, fruity note (X1) and woody note (X4) especially, emphasizing the existence of complex interactions occurring between odor notes. The interaction X1X4 was further investigated. The woody note has a positive effect when the fruity note is also in the mixture but tends to show a negative effect otherwise.     

Molecular orbital approach to odor molecules: Normal fatty acids and cyclamenaldehydes

Eight normal fatty acids and 24 cyclamenaldehydes were analyzed based on the molecular orbital theory using Computer-Aided Chemistry Programs (CAChe Programs) with PM3 parameters. We found reactive sites with high values of electrophilic frontier densities (EFDs) at appointed positions in both molecules. EFD is a theoretical index that predicts reactive sites acting as electron donors. A change in the values of EFDs in normal fatty acids would account for the selectivity in the response of a single olfactory receptor cell to the fatty acids. Changes in the values of EFDs at appointed positions of cyclamenaldehydes also correlated with their odor characteristics and intensities. This fact indicates that cyclamenaldehydes have common reactive sites that play a critical role in interactions with a receptor. Changes in their reactivities alter the odor characteristics and intensities of the molecules judged by perfumers, indicating that human discrimination of cyclamenaldehyde odor is determined at the stage of interaction between cyclamenaldehydes and an odor receptor. © 2000 John Wiley & Sons, Inc. Int J Quant Chem 79: 101–108, 2000