基于电子鼻技术的聚丙烯气味识别研究

首先优化了电子鼻检测参数,然后利用电子鼻技术研究了不同聚丙烯(PP)树脂气味差异以及主成分分析(PCA)模型对PP树脂样品的识别。结果表明,电子鼻检测优化参数设定为顶空温度120℃,顶空时间30 min;通过提取PP树脂特征气味建立的PCA模型可准确区分不同PP树脂样品气味响应强度的差异,并可快速有效识别PP树脂样品的气味大小。     

茶树花中功能性成分的提取与分析研究

采用分光光度法测定茶多酚、茶多糖等功能性成分含量;用高效液相色谱法测定茶多酚中儿茶素组成成分,离子色谱积分安培法测定多糖中单糖的组成成分。实验表明:茶树花中含茶多酚含量为3.62%~4.48%,总糖为16.15%~23.25%,其中茶多糖为1.60%~1.65%,茶氨酸为3.92%~5.03%,黄酮为0.141%~0.162%。分析结果表明茶树花中功能性成分与茶叶中的成分相似,为进一步开发利用茶树花资源提供理论依据。     

ICP-MS结合化学计量学分析三七花中无机元素的含量

运用电感耦合等离子体质谱(ICP-MS)法测定不同栽培土壤三七花中Pb、Cd、As、Hg、Cu等9种无机元素含量,同时采取化学计量学软件对三七花药材及其栽培土壤进行无机元素分析。发现在数据分析中,三七花中部分无机元素的富集与土壤呈明显相关性。且三七花的差异较小而其栽培土壤中所含无机元素差异相对较大。对所含无机元素进行研究分析,发现土壤中无机元素铅的相关性最显著,文山产区的土壤铅富集更高。     

基于仿生技术对不同产地茯苓品质的鉴别展望

自古以来,茯苓药材的产地变迁较大.如今茯苓产地复杂,在全国诸多省份都有栽培种植,然而对其质量的评价也缺乏客观的衡量标准.以往基于含量测定对不同产地茯苓的质量控制和评价不能全面地反映茯苓的整体质量,茯苓品质的评价应当与传统中医药理论相结合.中药的气、味特征是药材内在化学成分最直接的外在表现,电子鼻和电子舌技术可用...     

基于GA-BP神经网络的塑料X射线吸收光谱的辨识

采集15种塑料样本的X射线吸收光谱(XAS),对光谱数据进行预处理和主成分分析,建立误差反向传播(BP)神经网络和遗传算法优化的误差反向传播(GA-BP)神经网络模型,利用训练集进行网络训练,并通过测试集进行验证。结果表明,GA-BP神经网络相比于BP神经网络可以更好更稳定的对塑料样本的XAS进行识别,这对塑料的回收具有重要的指导意义。     

基于GA-BP神经网络的塑料X射线吸收光谱的辨识

采集15种塑料样本的X射线吸收光谱(XAS),对光谱数据进行预处理和主成分分析,建立误差反向传播(BP)神经网络和遗传算法优化的误差反向传播(GA-BP)神经网络模型,利用训练集进行网络训练,并通过测试集进行验证。结果表明,GA-BP神经网络相比于BP神经网络可以更好更稳定的对塑料样本的XAS进行识别,这对塑料的回收具有重要的指导意义。     

基于主成分分析方法的地震相分析技术研究

基于主成分分析方法的地震相分析技术,是继传统地震相分析(相面法)技术和基于神经网络的波形分类技术后发展起来的又一项新的地震相分析技术,它能实现多属性数据体同时划相,最终得到三维地震相数据体。克服了以往技术的某些缺陷,是研究沉积相和储层预测的重要手段之一。本文利用此地震相分析技术,针对SYB地区碳酸盐岩生物礁相储层进行了研究,在礁体内幕的刻画和相带边界的划分上取得了很好的效果。     

论电子通信技术的应用分析和网络构架

当前,我国经济发展速度逐渐加快,电子通信技术应用也出现了规模扩张的趋势.在这种情况下,为了进一步强化电子通信技术的实施效果,应当针对其主要应用方法进行分析,并结合网络构架,研究对应的基础细节.通过这种方式,能够显著提高整体技术应用质量,降低出现问题的概率,有利于未来的进一步发展.本文首先分析电子通信技术的基础概念,随后...     

基于GC-MS和主成分分析的蜂蜡质量控制方法研究

目的:为确保蜂蜡质量稳定可控,建立建全蜂蜡的质量控制方法。方法:收集14个不同产地的蜂蜡,利用柱前衍生化气质联用技术对蜂蜡中成分进行分析,利用指纹图谱对14个不来源不同的蜂蜡样品进行鉴定分析,随后采用主成分分析进行结果验证,并找出引起质量差异的化合物,建立简单快捷的质量评价方法。结果:主成分(PCA)分析的结果表明,存在样品质量差别的最明显原因可能是由化合物2、6、9、14、17、21、22、24、29、33、37、39、44等造成。结论:蜂蜡质量标准应该控制总烷酸类含量的同时也控制烷烃及游离烷酸的含量。     

Application of the Electronic Nose to the Classification of Resistance to Western Flower Thrips in Chrysanthemums

A metal oxide sensor-based electronic nose was tested for its ability to discriminate among chrysanthemum cultivars with varying degrees of resistance to western flower thrips (WFT), based on volatile chemicals released from cut leaves. Cultivars that were susceptible, intermediate, or resistant to WFT [based on mean cultivar rank (MCR)] were used as standards, and were correctly classified (> 90%) by using discriminant function analysis. Several cultivars with unknown resistance were classified based on the standards, and were used as standards in a subsequent trial to classify other unknowns. The results of this study demonstrate some agreement between the WFT resistance categories as designated by the electronic nose and results of feeding bioassays (MCR), suggesting that this technique may serve as a useful screening tool for WFT resistance. Contribution number S211 from the Food Research Program.     

Determination of Origin of Commercial Flavored Rapeseed Oil by the Pattern of Volatile Compounds Obtained via GC–MS and Flash GC Electronic Nose

Flavored rapeseed oil (FRO) is a typical hot‐pressed oil and is widely consumed in China due to its strong characteristic flavor and intensive color. In this study, volatile profiles of 33 representative commercial rapeseed oils in China are characterized by gas chromatography‐mass spectrometry (GC‐MS) and flash gas chromatography (GC) electronic nose system. 51 volatile compounds are identified and the nitriles (methallyl cyanide and 5‐cyano‐1‐pentene), aldehydes (nonanal, 3‐furaldehyde, and 5‐methyl‐2‐furancarboxaldehyde), alcohols (1,5‐hexadien‐3‐ol, 2‐furanmethanol, and phenylethyl alcohol), and pyrazines (2,5‐dimethyl‐pyrazine and 2,6‐dimethyl‐pyrazine) are the major volatile compounds in FROs. Glucosinolate degradation products account for the highest proportion of these volatiles, which are found to have a positive correlation with the erucic acid content (R² = 0.796, p < 0.01). FRO from Sichuan province in the southwest of China can be characterized by the obvious distinctions in flash GC electronic nose combined with principal component analysis, which indicates that the flash GC electronic nose can be used as a promising method to identify the origins of FRO. Practical Applications: This work is helpful for expanding the knowledge of volatiles of commercial flavored rapeseed oil. The data can also serve as a basis for the quality assessment of hot‐pressed rapeseed oil. Meanwhile, the flash GC electronic nose combined with principal component analysis can be used as a promising method for the classification of flavor rapeseed oil production areas.     

一种应用于电子舌系统的味觉敏感材料研究

通过硅氧烷染料(Azo-SiEO)和甲基三乙氧基硅烷(MTES)的水解聚合的溶胶凝胶方法,分别制备了Azo-PMS和PMS敏感膜材料,对制备工艺中较为重要的溶剂用量比对凝胶时间的影响进行了深入研究。将Azo-PMS和PMS敏感材料分别在电极表面成膜,采用伏安法对酸、甜、苦、咸、鲜5种标准味觉溶液进行测量,制作了味觉响应雷达图。通过雷达图发现,具有Azo-PMS敏感膜材料的电极对酸溶液产生了特异性的相应,其中的偶氮基团与溶液中的酸质子产生了可逆结合;而不含偶氮基团的PMS材料则其电导率只依赖于溶液中电解质的简单扩散,其中对咸味(KCl)要敏感些,可将它们分别应用作为电子舌酸味和咸味的检测阵列单元。     

电子舌及其在食品新鲜度方面的研究进展

电子舌技术是20世纪80年代中期发展起来的一种分析、识别食品味道的新型检测手段。它与普通化学仪器不同,得到的不是被测样品的一种或几种成分定量的结果,而是样品成分的整体信息。本文介绍了电子舌的工作原理及其在食品新鲜度区分辨识中的研究进展,并对电子舌的发展趋势作了展望。     

电子舌及其在水体污染检测方面的研究进展

电子舌技术经历了一段较长的发展历程,近些年来由于应用前景广阔,电子舌得到了很大发展。电子舌技术检测到的不是被测样品中的某种或某几种成分的定性或定量结果,而是样品成分的整体信息。本文介绍了电子舌的工作原理及电子舌技术在水体污染检测方面的应用情况,在此基础上对电子舌技术在水体污染检测方面的应用前景进行了展望。     

Discrimination of Olive Oil by Cultivar,Geographical Origin and Quality Using Potentiometric Electronic Tongue Fingerprints

Legal regulations are set for protecting claims regarding olive oil geographical denomination. When meteorological or agroecological factors similarly affect different regions, the origin identification is a challenging task. This study demonstrated the use of a potentiometric electronic tongue coupled with linear discriminant analysis to discriminate the geographical origin of monovarietal Tunisian olive oil produced from local cv Chemlali (Kairouan, Sidi Bouzid or Sfax regions) and cv Sahli (Kairouan, Mahdia or Sousse regions). The potentiometric fingerprints of 12 or eight lipid sensors (for Chemlali and Sahli, respectively), selected using a simulated annealing meta-heuristic algorithm, allowed the correct prediction (repeated K-fold cross-validation) of the geographic production region with sensitivities of 92 ± 7% (Chemlali) and 97 ± 8% (Sahli). It was also confirmed the electronic tongue capability to classify Tunisian olive oil according to olive cultivar or quality grade. The results indicated the possible use of potentiometric fingerprints as a promising innovative strategy for olive oil analysis allowing assessing geographical origin, olive cultivar and quality grade, which are key factors determining olive oil price and consumers’ preference.     

Potential of the Electronic Nose for the Detection of Respiratory Diseases with and without Infection

Respiratory tract infections are common, and when affecting the lower airways and lungs, can result in significant morbidity and mortality. There is an unfilled need for simple, non-invasive tools that can be used to screen for such infections at the clinical point of care. The electronic nose (eNose) is a novel technology that detects volatile organic compounds (VOCs). Early studies have shown that certain diseases and infections can result in characteristic changes in VOC profiles in the exhaled breath. This review summarizes current knowledge on breath analysis by the electronic nose and its potential for the detection of respiratory diseases with and without infection.     

Characterization of Differences in Flavor in Virgin Rapeseed Oils by Using Gas Chromatography–Mass Spectrometry,Electronic Nose,and Sensory Analysis

Flavor profiles of virgin rapeseed oils (VROs) are comparatively studied for the discrimination and authentication of various flavor types by using gas chromatography–mass spectrometry (GC‐MS), electronic nose (E‐nose), and sensory analysis. The relative odor activity values (ROAVs) of key odorants detected by GC‐MS and E‐nose data are visualized to discriminate VROs with various flavors by using multivariate analysis. The correlation of sensory data, ROAVs of key odorants, and E‐nose data is analyzed. Results show that 47 key odorants comprising aldehydes, isothiocyanates, nitriles, pyrazines, ketones, acids, and alcohols are identified based on their ROAVs. The VROs are divided into three groups and the flavor type of each group is determined, namely, green‐pungent, nutty, and oxidized oil flavor by the three techniques. The above flavor types are mainly attributed to the contributions of isothiocyanates, pyrazines, and aldehydes, respectively, according to the compounds' ROAVs. The correlation of the three techniques is investigated by partial least squares regression: GC‐MS data are confirmed to have good correlation with sensory data. Practical Applications: VROs are characterized by their intense flavor and consequently receiving growing interest among consumers. In this study, different flavor profiles of VROs were comparatively studied using GC‐MS, E‐nose, and sensory analysis. It is found that 47 volatile compounds including aldehydes, isothiocyanates, nitriles, pyrazines, ketones, acids, and alcohols were the key odorants to VRO flavors. The VROs were divided into three types by the three techniques, that is, green‐pungent, nutty, and oxidized oil flavor. The three flavor types were attributed to the contributions of isothiocyanates, pyrazines, and aldehydes, respectively, based on the compounds' ROAVs and GC‐MS was confirmed to have good correlation with sensory data. Although E‐nose cannot correlate all flavor types in the oils, this technique is rapid and low‐cost for VRO discrimination according to various aroma characteristics. GC‐MS and E‐nose can be regarded as potential techniques for flavor discrimination in VROs.     

UHT脱脂纯牛奶感官评价和电子鼻分析相关性研究

选取四种市售不同品牌的UHT脱脂纯牛奶作为研究对象,通过感官描述性分析和电子鼻技术对其风味属性进行评价。采用主成分分析(PCA)和聚类分析(CA)结合偏最小二乘回归法(PLSR)法将电子鼻传感器性能和感官属性进行相关性分析。结果表明样品奶油味及脂质感评分均较低;电子鼻的十个传感器对四个样品的区分效果良好;基于感官属性和传感器响应值的PLSR分析建立的相关性模型,能够很好地解释感官属性和传感器响应值的相关性,反映脱脂纯牛奶样品的整体信息。本文结合两种技术方法,弥补了人工感官评价存在的主观性与智能感官分析的局限性影响,旨在为后续改善脱脂纯牛奶风味提供技术参考。