超临界流体萃取茶叶香气成分的研究

采用超临界流体萃取技术提取茶叶中的香气成分,研究温度、压力、时间、CO2流量对超临界流体萃取得率的影响,通用正交实验法进行最佳工艺优化并对产物进行GC/MS定性分析.结果表明:萃取时间4 h、萃取温度50 ℃、CO2流量8 L/h、萃取压力30 MPa时得率为2.82%,共鉴定出28种香味成分.     

茅台啤酒风味物质超临界萃取GC-MS分析研究

采用超临界萃取,以气相色谱-质谱法对茅台啤酒的风味物质进行定性分析.从茅台啤酒的超临界萃取物中分离了43种成分,鉴定了其中的36种成分,其相对含量占总离子峰的90.51%.结果表明,醇类和含羰基化合物是构成茅台啤酒风味的主要物质,其中醇类物质的相对含量高达56.529%,并以丙三醇的相对含量最高,达24.235%;而含羰基化合物的相对含量达44.219%,其中以有机酸类的相对含量最高,为19.228%.     

超临界CO_2萃取柚子叶、花精油的GC-MS分析

采用超临界CO2萃取技术提取柚子叶、花中的精油,运用气相色谱-质谱(GC-MS)联用技术对其化学成分进行分离和鉴定,并用峰面积归一化法确定各组分的相对含量。结果表明:从柚子叶精油中分离出61个色谱峰,鉴定出39个化合物,占总离子峰相对含量的90.05%。其主要化学成分有匙叶桉油烯醇(21.36%),石竹烯氧化物(17.16%),β-石竹烯(8.40%),α-石竹烯(2.07%),异芳萜烯氧化物(2.01%)等。从柚子花精油中分离出42个色谱峰,鉴定出27个化合物,占总离子峰相对含量的89.31%。其主要化学成分有金合欢醇(19.02%)、橙花叔醇(18.24%),龙脑(6.60%),芳樟醇(4.03%),橙花醇(2.57%)等。柚子叶与柚子花精油共同鉴定出的化合物有橙花醇、香叶醇、香叶酸、β-石竹烯等12种,其相对含量存在不同程度差异。     

Application of supercritical fluid extraction (SFE) to predict bioremediation efficacy of long-term composting of PAH-contaminated soil

Supercritical fluid extraction (SFE) with pure carbon dioxide was used to obtain desorption curves of PAHs from four contaminated industrial soils. Total PAH concentrations ranged from 1495 to 2439 mg/kg. The desorption curves were fitted with a simple two-site model to determine the rapidly released fraction (F) representing bioavailability of PAHs. The Fdata obtained under various SFE pressures were compared with degradation results of a composting method applied on the soils. After composting and consequent long-term maturation, the residual PAH contaminations ranged from 4 to 36% of the original values. A possible explanation of the result variations is the different bioavailability of the pollutants. The best correlations between degradation results and F fraction were obtained applying 50 degrees C and 300 bar. The F values gave very good agreement with degradation efficiencies and the total regression coefficients (r) ranged from 0.81 to 0.99. The degradation results together with bioavailable fractions appeared to be consistentwith organic carbon contents in the soils and with volatile fractions of organics. The results indicate that SFE could be a rapid testto predict bioremediation results of composting of PAH-contaminated soils.     

超临界CO2萃取技术在茶多酚提取中的应用

以绿茶为材料,采用超临界萃取技术提取绿茶中的茶多酚,并采用正交试验对压力、温度、时间、夹带剂等条件进行了优化.结果表明,在时间为1 h、温度60 ℃、压力25 MPa时,茶多酚萃取率为43.68%.当加入浓度为65%乙醇作为夹带剂,茶多酚萃取率可提高到56.37%.     

大蒜超临界CO2萃取物成分分析

对大蒜超临界CO2萃取物进行了GC-MS分析，借助NTST98.L数据库的质谱图数据，参考文献和人工解析对其中的20多种组分进行，定性鉴定，并利用峰面积归一化法进行了初步定量。大蒜风味物的GC-MS分析表明：大蒜超临界CO2萃取物中含有许多水蒸汽蒸馏蒜油中没有检测到的风味成分，其中最显蔷的是蒜素色谱分析中脱水衍生的3-乙烯基-l，2-二硫杂-4-环已烯(3．96％)及3-乙烯基-1．2-二硫杂-5-环己烯(17．88％)，此外还含有少量的亚油酸及油酸。     

超临界流体(二氧化碳)萃取技术在食品配料中的应用

<正> 随着食品工业的发展,食品添加剂已成为加工食品不可缺少的基料。它们对改善食品的质量、档次和色香味,原料至成品的保质保鲜,提高食品的营养价值,新产品的开发,食品加工工艺的顺利进行等方面,都起着极为重要的作用。 超临界流体萃取技术,是近年迅速发展起来的一项高新技术。超临界流体是一种同时拥有类似液体密度和气体粘度特性的流体,具有高扩散性、低粘性、无污染、不易燃等良好溶剂的优点,其溶解能力能根据其体系的温度和压力等因素发生连续性变化。根据这一特点,我们可以通过改变流体体系的温     

Validation study on a method for multiresidue analysis of pesticides in vegetables and fruits with supercritical fluid extraction

Supercritical fluid extraction (SFE) was applied to extraction of pesticides from vegetables and fruits. Residues were extracted from homogenized samples mixed with water-absorbent polymer with supercritical carbon dioxide in a stainless steel tube, followed by elution with acetone. Co-extractives were removed by means of mini-column clean-up. Measurement was performed by GC-MS/MS. Calibration was achieved by preparing matrix-matched calibration standards to counteract matrix effects. With the Japanese method validation guideline as a reference, the method was assessed in 5 agricultural products spiked with 334 pesticides at 0.01 and 0.1 μg/g. Compounds at each level were extracted from 2 samples on 5 separate days. The trueness of the method for 189 pesticides in all samples was 70-120%, and the repeatability and within-run reproducibility were also consistent with the guideline. The trueness of the method for the other 71 pesticides was in the range of 50-70%, though the repeatability and within-run reproducibility were satisfactory. This method is available as a multiresidue analysis method for vegetables and fruits.     

超临界CO2流体萃取芦荟大黄素的研究

研究了超临界流体萃取芦荟中的芦荟大黄素的工艺,考察了萃取温度、压力和时间对芦荟大黄素萃取率的影响。结果表明,分离釜的温度、压力和CO2流量对萃取效率影响较小;最佳萃取条件为:静萃取时间为60min、动萃取时间为30 min、萃取压力25 MPa、萃取温度30℃、乙醇用量250 mL/100g,在此条件下芦荟大黄素的萃取量达3.83 mg/100g。     

超临界CO2萃取香草兰的工艺研究和成分分析

进行超临界CO2萃取香草兰豆荚的工艺研究，探索萃取压力和温度，分离压力和温度以及萃取时间与萃取率之间的关系。确定出最佳的工艺条件为：萃取压为35MPa，萃取温度45℃，分离（Ⅰ）压力16MPa，分离（Ⅰ）温度40℃，分离（Ⅱ）压力6MPa，分离（Ⅱ）温度40℃，萃取时间150min。用GC／MS分析萃取物的化学成分，鉴定出27种化合物，其中香素的相对含量最高，为26．06％。     

超临界萃取GC-MS分析桂皮油成分研究

采用了超临界萃取技术从桂树皮中提取桂皮油,并改变萃取的温度和压力以得到最合适的萃取条件,然后通过气-质谱联用仪分析所得桂皮油的组分并对各个组分的相对含量进行测定。结果表明：在相对较低的压力下就可以获得高质量的桂皮油。其最佳提取工艺条件为：萃取压力为120bar,萃取温度为45℃,萃取时间为150min,桂皮油的得率为3．75％。另外利用气-质联用仪对桂皮油的组分和个组分的相对含量进行了测定,鉴定出41个组分,其中主要组分有：桂皮醛、桂皮酸、丁香酚、T-依兰油醇、T-毕澄茄醇等。     

微波-同时蒸馏萃取红薯叶茶香气成分及其GC-MS分析

采用微波-同时蒸馏法提取红薯叶茶的香精油,然后经气相色谱-质谱联用技术对香气成分进行分离鉴定,共鉴定出97种成分,占红薯叶茶香气成分总峰面积的83.95％.其中主要香气成分为α-荜澄茄烯醇(1.07％)、1,2,3,4,4α,7-六氢化-1,6-二甲基-4-(1-甲基乙基)萘(1.22％)、(1S-cis)-1,2,3,5,6,8α-六氢化-4,7-二甲基-1-(1-甲基乙基)萘(1.32％)、2,6-二甲基-6-(4-甲基-3-戊烯基)-双环[3.1.1]庚-2-烯(1.37％)、γ-榄香烯(1.38％)、叶绿醇(1.65％)、石竹烯氧化物(2.07％)、8-异丙基-1,5-二甲基-环十碳-1,5-二烯(8.49％)、石竹烯(14.61％)等.鉴定的物质大多数为萜烯类及其衍生物,具有一定的生理活性.     

微波-同时蒸馏萃取红薯叶茶香气成分及其GC-MS分析

采用微波-同时蒸馏法提取红薯叶茶的香精油,然后经气相色谱-质谱联用技术对香气成分进行分离鉴定,共鉴定出97种成分,占红薯叶茶香气成分总峰面积的83.95%。其中主要香气成分为α-荜澄茄烯醇（1.07%）、1,2,3,4,4α,7-六氢化-1,6-二甲基-4-（1-甲基乙基）萘（1.22%）、（1S-cis）-1,2,3,5,6,8α-六氢化-4,7-二甲基-1-（1-甲基乙基）萘（1.32%）、2,6-二甲基-6-（4-甲基-3-戊烯基）-双环[3.1.1]庚-2-烯（1.37%）、γ-榄香烯（1.38%）、叶绿醇（1.65%）、石竹烯氧化物（2.07%）、8-异丙基-1,5-二甲基-环十碳-1,5-二烯（8.49%）、石竹烯（14.61%）等。鉴定的物质大多数为萜烯类及其衍生物,具有一定的生理活性。      

超临界CO2萃取槟榔精油的GC-MS分析

以海南产槟榔为实材,采用超临界CO2流体萃取的方法提取槟榔子中的精油,并借助气质联用仪分析槟榔精油成分,从气质分析所得总离子流色谱图中共分离出105个峰,利用随机GC-MSSolution工作站美国国家标准谱图库(NIST-MS,2005)自动检索各组分质谱数据,共检出87种化合物并且确定了其化合物结构。研究结果表明:超临界提取所得精油以醇、酸、烷烃类为主,其中醇类相对含量为49.79%,酸类相对含量为17.76%,烃类相对含量8.31%。功能性成分如甾醇、维生素E、反式角鲨烯所占比例较高,为研究槟榔油的生理功能提供了理论依据。     

广藿香超临界流体萃取研究

研究了温度、压力、时间、CO2流量对超临界流体萃取广藿香产物得率的影响,并进行了最佳工艺优化。结果表明,广藿香CO2流体萃取的最佳工艺条件为：萃取压力30MPa、萃取温度50℃、CO2流量9kg／h,在此条件下产物得率为2．55％。     

Multiresidue analysis of pesticides in agricultural products by GC/MS,GC-ECD and GC-FTD using acetonitrile extraction and clean-up with mini-columns

An analytical method was developed for determination of organochlorine, pyrethroid and nitrogen-containing pesticide residues in agricultural products by GC/MS, GC-ECD and GC-FTD. Pesticides were extracted with acetonitrile, and the organic layer was cleaned up on C18 and ENVI-Carb/LC-NH2 cartridges. Pesticides were determined by GC/MS, GC-ECD and GC-FTD. Detection limits of pesticides by GC/MS and GC were below 1-30 ng/g and 1-3 ng/g, respectively. Recoveries of 27 out of 53 pesticides determined by GC/MS and 47 out of 53 determined by GC were 70-120%. This method was useful for the multiresidue analysis of pesticides in agricultural products. Pesticide residues in 81 domestic crops were investigated from April 2001 to March 2002. Residues of 31 pesticides were detected from 21 crops.     

浊点萃取-气相色谱-质谱法测定苹果汁中的有机磷农药残留

本文对苹果汁中45种有机磷类农药的提取、净化技术和气相色谱质谱检测条件进行了研究。以苹果汁为基质材料,45种有机磷类农药在1、5、10μg/L三个水平上对苹果汁进行添加回收率实验。结果表明:45种有机磷类目标物在优化条件下的回收率为71.16%~117.94%,相对标准偏差1.20%~15.13%(n=5),方法检出限为0.01~0.22μg/L。45种有机磷类农药能够实现很好的分离,线性范围在10~2000μg/L,线性相关系数大于0.984。本方法操作简单,结果准确,由于几乎不使用有机溶剂也减少了分析过程对环境和人体的危害。      

超临界CO2萃取GC－MS分析八角茴香油成分

为了确保八角茴香油的质量,采用超临界流体技术,在不同的萃取时间,萃取压力,萃取温度下,从八角茴香果中提取八角茴香油,并通过GC-MS分析方法测定其主要化学成分为反式茴香醚,草蒿脑,茴香醛.本实验重点探讨这三种成分在不同条件下的变化规律.通过实验,可知其适宜粒度范围为0.5～2mm,最适宜萃取时间,萃取压强,萃取温度分别为:2h,200bar,50℃.