无溶剂微波提取-气相色谱-质谱法测定八角挥发油

将干八角粉碎至过2.00mm孔径的药筛,取20g样品间歇性喷雾加水至其含水量(质量分数)达50%,置于圆底烧瓶中,用LWMC-204微波化学反应器在180W微波功率进行无溶剂微波辅助提取(SFME),所得提取液用无水硫酸钠干燥置于4℃保存。此溶液用于气相色谱-质谱法测定其中的挥发油组分,将所得结果与SFME法和水蒸气蒸馏法(SD)所得数据对比,可知SFME法提取挥发油有以下特点:①该法仅需30min提取即可达到其最高提取率7.71%;②经此法分离后在挥发油中共测得25种化合物,达总量为98.94%;③所测得的含氧单萜类化合物高于SD法提取所得;④所测得挥发油的主要成分反式茴香脑的含量较SD法提取所得的量高1.4倍。     

微波辅助固相顶空-气相色谱法直接测定乙烯-醋酸乙烯共聚塑料中的苯乙酮

通过微波无溶剂提取与顶空气相色谱在线联用,建立了一种可直接快速检测固体样品中挥发性成分苯乙酮的方法,考察了微波加热时间对灵敏度和重现性的影响.苯乙酮峰面积随微波加热时间的延长呈现先增加后减小的趋势,短时间微波辐射下苯乙酮峰面积的重现性优于长时间微波辐射.本方法的线性范围为0.003～0.333 mg/g;检出限为2.022 μg/g.与常规加热的顶空气相色谱法相比,本方法简便、省时、重现性好.对苯乙酮与共存物峰面积比随时间变化的研究结果表明,短时间微波加热有利于实现极性组分的选择性提取.     

基于离子液体的静态顶空气相色谱技术

综述了近年来离子液体作为顶空溶剂静态顶空气相色谱法或气相色谱质谱法联用技术在挥发性成分的样品前处理中的研究进展,主要是其在药物、食品、空气等样品中的挥发性成分包括有机溶剂残留、活性成分、基因毒性杂质、农药残留等的顶空分析研究与应用和有机溶剂残留顶空分析的理论研究,并探讨了离子液体作为顶空溶剂的静态顶空气相色谱技术存在的问题和未来发展方向。     

顶空固相微萃取-气相色谱-质谱联用分析干柴胡药材中有机挥发物

采用顶空固相微萃取与气相色谱-质谱联用技术检测分析干柴胡药材中挥发性成分,选用聚丙烯酸酯涂层,就萃取时间、温度、体积、样品量、预热时间及脱附时间等条件进行了优化,结果表明,30mL萃取瓶里0．5g样品90℃温度下预热40min后,以85μmPA涂层顶空萃取50min,于250℃脱附5min,测得88个峰,鉴定26种化合物成分。方法所得结果与传统提取方法(蒸馏提取法)比较,相对含量较高的成分一致,方法重现性理想,可应用于柴胡药材挥发性物质的快速分析。     

顶空固相微萃取-气相色谱-质谱法快速测定酱油中的挥发性风味成分

建立了一种快速简便地测定酱油中挥发性风味成分的顶空固相微萃取（HS-SPME）-气相色谱-质谱法(GC-MS)。以2-辛醇为内标,考察了萃取头、萃取时间、离子强度、萃取温度对酱油样品中挥发性风味物质萃取的影响。该方法对酱油中常见挥发性风味成分的测定有良好的重复性和回收率,对常见挥发性物质的定量比较准确。优化的HS-SPME条件为：涂层厚度为85 μm聚丙烯酸酯(PA)萃取纤维头,于45 ℃、NaCl质量浓度为250 g/L下对酱油样品顶空吸附40 min,于250 ℃下解吸2 min后进行GC-MS分离鉴定。酱油样品的分析结果表明,其挥发性风味物质中含量较高的是醇、酸、酯和酚类,此外还有一些羰基化合物和杂环化合物。     

姜科姜黄属植物有效成分的研究

研究不同产地姜科姜黄属植物挥发油的化学成分,了解不同产地姜科姜黄属植物挥发性成分的差别,为控制其药材质量提供理论依据。采用水蒸气蒸馏法提取不同产地姜科姜黄属植物的挥发油,用气相色谱—质谱联用仪对其进行分离测定,结合计算机检索对分离的化合物进行结构鉴定,应用色谱峰面积归一化法测定各成分的相对百分含量。结果发现,不同产地姜科姜黄属植物的水蒸气蒸馏提取物得率在0．20％～2．13％之间,分别鉴定出24～40个化学成分。不同品种、不同产地姜科姜黄属植物的挥发油含量和其所含成分有较大差别,文献报道的某些有效成分如莪术酮、莪术二酮、莪术醇和表莪术酮在某些供试品中未检测到。实验中10个供试品药材中挥发性成分主要为单萜类及倍半萜类化合物及其衍生物,倍半萜类化合物的百分含量(44．57％～88．65％)明显高于单萜类化合物的百分含量(1．63％～26．69％)。     

固相微萃取-气相色谱-质谱分析牡丹花的挥发性成分

用固相微萃取装置（SPME）顶空提取牡丹花的挥发性成分,采用气相色谱-质谱（GC-MS）联用技术定性分析不同品种牡丹花的挥发性成分,归一法计算其相对百分含量,同时对SPME与水气蒸馏提取效果进行了比较。10个品种牡丹花共检出34种成分,其中多数是烷烃。不同品种牡丹花的成分与相对百分含量不同,少量的醇、酯、烯等成为其特有成分。     

动态微波辅助顶空固相微萃取-气相色谱-质谱法测定芹菜叶中的化学成分

采用动态微波辅助顶空固相微萃取结合气相色谱-质谱法测定芹菜叶中的挥发性和半挥发性化学成分。对水蒸气蒸馏、顶空固相微萃取、微波辅助顶空固相微萃取、动态微波辅助顶空固相微萃取等4种不同的前处理方法进行了比较,通过气相色谱-质谱分析,分别鉴定出20,17,36,41种化学成分,主要化合物为α-月桂烯、柠檬烯、β-顺式罗勒烯、β-芹子烯和(Z)-3-己烯-1-醇等。结果表明:动态微波辅助顶空固相微萃取是一种简单、快速、易操作,无需净化步骤,消耗样品量少,对于沸点较高的半挥发性物质的萃取效果优于微波辅助顶空固相微萃取的方法,可用于分析各类植物中的挥发性和半挥发性化学成分。     

顶空气相色谱标准加入法测定自来水中的一溴二氯甲烷和二溴一氯甲烷

用于测定水中三卤甲烷的方法主要有吹扫捕集热解吸法和液液萃取法,固相微萃取技术与顶空法相结合也被应用于测定水中的挥发性卤代烃。我国水和废水标准方法规定用静态顶空外标方法测定三卤甲烷。作者曾报道了改变相比／顶空色谱法测定水中氯仿及其分配常数的方法。本文主要研究顶空气相色谱标准加入法测定城市自来水中的一溴二氯甲烷和二溴一氯甲烷。与顶空气相色谱外标法比较,该法避免了水样基体及色谱条件对测定结果的影响。与顶空气相色谱内标法比较,该法不用另外选择内标物,操作方便。     

顶空气相色谱在化学研究中的应用

顶空气相色谱（headspace gas chromatography,简称HSGC）是将顶空样品预处理系统（headspace）和气相色谱结合使用的技术,具有简单、迅速、准确和自动化等优点,已经在商品检测、药品检测等常规检测中发挥重要作用。巧妙利用其顶空系统可以在化学分析测定中发挥更大的作用,能够测定挥发性化学物质的气液平衡常数（亨利常数）、无机盐的溶解度、高分子聚合过程单体含量等,还可解决化工工程样品分析中的复杂问题,以及应用于环境和其它工业过程化学成分含量的分析。     

Solvent-free microwave extraction and hydrodistillation of essential oils from endemic Origanum husnucanbaseri H. Duman, Aytac & A. Duran: comparison of antibacterial activity and contents

The essential oils (EOs) obtained by solvent-free microwave extraction (SFME) and hydrodistillation (HD) from endemic Origanum husnucanbaseri H. Duman, Aytac & A. Duran were investigated using the gas chromatography-mass spectrometry system. The main constituents of both oils obtained from SFME and HD from O. husnucanbaseri are borneol (15.2-12.8%), α-terpineol (12.3-10.8%) and trans-sabinene hydrate (11.8-9.92%). The EO obtained from SFME contained substantially higher amounts of oxygenated compounds and lower amounts of monoterpenes than that from HD. The antibacterial activities of the EOs from SFME and HD were evaluated by the disc diffusion method against six bacterial strains. The EO extracted by SFME was more effective than the EO extracted by HD against the tested bacteria, except for Klebsiella pneumoniae American type culture collection (ATCC) 13883. Streptococcus pyogenes ATCC 19615 and Staphylococcus aureus ATCC 25923 in particular were more sensitive against the EO extracted by SFME.     

Solvent-free microwave extraction of essential oil from aromatic herbs: comparison with conventional hydro-distillation

Solvent-free microwave extraction (SFME) is a combination of microwave heating and dry distillation, performed at atmospheric pressure without added any solvent or water. Isolation and concentration of volatile compounds are performed by a single stage. SFME has been compared with a conventional technique, hydro-distillation (HD), for the extraction of essential oil from three aromatic herbs: basil (Ocimum basilicum L.), garden mint (Mentha crispa L.), and thyme (Thymus vulgaris L.). The essential oils extracted by SFME for 30min were quantitatively (yield) and qualitatively (aromatic profile) similar to those obtained by conventional hydro-distillation for 4.5 h. The SFME method yields an essential oil with higher amounts of more valuable oxygenated compounds, and allows substantial savings of costs, in terms of time, energy and plant material. SFME is a green technology and appears as a good alternative for the extraction of essential oils from aromatic plants.     

Chemical composition and antibacterial activity of Origanum saccatum P.H. Davis essential oil obtained by solvent-free microwave extraction: comparison with hydrodistillation

The components of the essential oils (EOs) obtained by solvent-free microwave extraction (SFME) and hydrodistillation (HD) from endemic Origanum saccatum P.H. Davis were identified by using GC/MS. The main constituents of both EOs obtained by SFME and HD, respectively, from O. saccatum were p-cymene (72.5 and 70.6%), thymol (9.32 and 8.11%), and carvacrol (7.18 and 6.36%). The EO obtained by SFME contained substantially higher amounts of oxygenated compounds and lower amounts of monoterpenes than did the EO obtained by HD. The antibacterial activities of the EOs obtained by SFME and HD were evaluated with the disc diffusion method by comparison with 10 different bacterial strains. The antibacterial activity of the EO extracted by SFME was found to be more effective than that of the EO extracted by HD against seven of the tested bacteria.     

Effects of solvent-free microwave extraction on the chemical composition of essential oil of Calamintha nepeta (L.) Savi compared with the conventional production method

The essential oil of Calamintha nepeta has been obtained by solvent-free microwave extraction (SFME) and by classical hydrodistillation (HD). A comparative qualitative-quantitative study on the composition of the oils was carried out. A total of 38 compounds, constituting 97.6% of the oil, were identified in the oil obtained by SFME, whereas 46 compounds, representing 95.4% of the oil, were characterized in the HD oil. SFME-distilled oil is richer in lightly oxygenated monoterpenes (LOM) than HD oil. It also has a higher amount of sesquiterpenes and a lower quantity of hydrocarbon monoterpenes. HD oil seems to be affected by chemical changes more than SFME oil.     

Improved solvent-free microwave extraction of essential oil from dried Cuminum cyminum L. and Zanthoxylum bungeanum Maxim

Solvent-free microwave extraction (SFME) is a recently developed green technique which is performed in atmospheric conditions without adding any solvent or water. SFME has already been applied to extraction of essential oil from fresh plant materials or dried materials prior moistened. The essential oil is evaporated by the in situ water in the plant materials. In this paper, it was observed that an improved SFME, in which a kind of microwave absorption solid medium, such as carbonyl iron powders (CIP), was added and mixed with the sample, can be applied to extraction of essential oil from the dried plant materials without any pretreatment. Because the microwave absorption capacity of CIP is much better than that of water, the extraction time while using the improved SFME is no more than 30 min using a microwave power of 85 W. Compared to the conventional SFME, the advantages of improved SFME were to speed up the extraction rate and need no pretreatment. Improved SFME has been compared with conventional SFME, microwave-assisted hydrodistillation (MAHD) and conventional hydrodistillation (HD) for the extraction of essential oil from dried Cuminum cyminum L. and Zanthoxylum bungeanum Maxim. By using GC-MS system the compositions of essential oil extracted by applying four kinds of extraction methods were identified. There was no obvious difference in the quality of essential oils obtained by the four kinds of extraction methods.     

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。     

Layered double hydroxide/poly(vinylpyrrolidone) coated solid phase microextraction Arrow for the determination of volatile organic compounds in water

Today, wide variety of adsorbents have been developed for sample pretreatment to concentrate and separate harmful substances. However, only a few solid phase microextraction Arrow adsorbents are commercially available. In this study, we developed a new solid phase microextraction Arrow coating, in which nanosheets layered double hydroxides and poly(vinylpyrrolidone) were utilized as the extraction phase and poly(vinyl chloride) as the adhesive. This new coating entailed higher extraction capacity for several volatile organic compounds (allyl methyl sulfide, methyl propyl sulfide, 3‐pentanone, 2‐butanone, and methyl isobutyl ketone) compared to the commercial Carboxen 1000/polydimethylsiloxane coating. Fabrication parameters for the coating were optimized and extraction and desorption conditions were investigated. The validation of the new solid phase microextraction Arrow coating was accomplished using water sample spiked with volatile organic compounds. Under the optimal conditions, the limits of quantification for the five volatile organic compounds by the new solid phase microextraction Arrow coating and developed gas chromatography with mass spectrometry method were in the range of 0.2‐4.6 ng/mL. The proposed method was briefly applied for enrichment of volatile organic compounds in sludge.     

Extraction of the Volatile and Semivolatile Compounds in Seeds of Cuminum cyminum L. Using Hydrodistillation Followed by Headspace-Ionic Liquid-Based Single-Drop Microextraction

Hydrodistillation (HD) coupled with headspace single-drop microextraction by using ionic liquid (IL) as the extraction solvent, followed by gas chromatography analysis technique, was successfully developed to determine the volatile and semivolatile compounds in seeds of Cuminum cyminum L. In the proposed method, a 1.5-??L microdrop of 1-octyl-3-methylimidazolium hexafluorophosphate, working as the extraction solvent was suspended in the headspace of a 50-mL round-bottom sample flask. After extracting for 30?min, both IL and target analytes were injected into the gas chromatographic system by thermal desorption for 5?s under 240?°C. Then, the IL was retracted back to the microsyringe. Thus, the capillary column should not be contaminated and a clean chromatogram was obtained. The parameters affecting extraction performance were investigated and optimized. The extraction efficiency of the proposed method was compared with that of HD, which is a standard extraction method. The contents of constituents in the extract obtained by the proposed method were close to those obtained by HD. It seems to be an environmentally friendly, time-saving, high efficiency and low solvent consumption technique and would be useful, especially for aromatic plants analysis.     

Characterization of Sulfur-Compounds as Chemotaxonomic Markers in the Essential Oils of Allium Species by Solvent-Free Microwave Extraction and Gas Chromatography–Mass Spectrometry

Allium species were examined to authenticate the chemotaxonomic controversy about these plants by analyzing their extracted compound profiles. Essential oils of various species were isolated using conventional hydro-distillation and solvent-free microwave extraction (SFME). A comparison of the isolation procedures was performed. The presence of sulfur compounds in the Allium genus is a prominent characteristic for their medicinal uses. These components were characterized using two-way hierarchical cluster analysis (HCA) and principal component analysis (PCA). The variation of sulfur-compounds was performed by qualitative analysis of Allium species by gas chromatography–mass spectrometry (GC–MS). 2,4-Dimethyl-5,6-dithia-2,7-nonadienal, 4,6-diethyl-1,2,3,5-tetrathiolane, and 5,7-diethyl-1,2,3,4,6-pentathiepane were revealed as potential chemotaxonomic markers for all of the Alliums examined in this study. These markers may be used to provide improved systematics for other Allium species.     

Antibacterial activities of essential oils extracted from leaves of Murraya koenigii by solvent-free microwave extraction and hydro-distillation

Solvent-free microwave extraction (SFME) for the isolation of essential oil from leaves of Murraya koenigii L. (Rutaceae) has been compared with the conventional hydro-distilled oil (HD) in terms of yield, composition, antioxidant activity, and antibacterial activity against Listeria innocua. The yield of essential oil obtained from 30 min of SFME was similar to that of HD for 180 min. By GC-MS analysis, the major compounds of the essential oil extracted by SFME, which were obtained in somewhat lower amounts than in the essential oil obtained by HD, were alpha-copaene (44.3%), beta-gurjunene (25.5%), isocaryophyllene (12.1%), beta-caryophyllene (8.7%) and germacrene D (2.9%). The content of oxygenated terpenes, slightly higher for the SFME-essential oil (2.3%) than the HD-essential oil (1.4%), were much lower than that of nonoxygenated terpenes in both oils. DPPH radical scavenging activities of both essential oils were relatively low (10%-24%). Complete inhibition of growth of L. innocua was observed with both SFME and HD essential oils, at 400 and 600 microg/mL (minimum inhibitory concentration), respectively. The SFME-essential oil at 300 microg/mL provided 92% inhibition, indicating its potential as a natural antimicrobial agent.