Comparison of volatile and semivolatile compounds from commercial cigarette by supercritical fluid extraction and simultaneous distillation extraction

Supercritical carbon dioxide fluid extraction (SFE) was studied as a rapid method for extraction of volatile and semivolatile compounds of Chinese commercial cigarettes. The method was compared with simultaneous distillation and extraction (SDE). Temperature and pressure for the SFE were optimized. The extracts obtained by the two methods showed different characters in composition and represented differently the flavor characteristics of tobacco; compared to SDE, SFE can extract compounds within a shorter time and avoid the thermal degradation and solvent contamination of samples. The extracts by the two extraction methods are complementary for investigating the flavor characteristic of tobacco products.     

蜂蜜挥发性成分的SPME-GC/MS分析

利用固相微萃取及同时蒸馏萃取法对蜂蜜的挥发性成分进行提取,采用GC/MS方法进行分离、鉴定.2种方法共鉴定挥发性成分37种,其中PA固相微萃取法鉴定了24种,PDMS方法鉴定了18种,同时蒸馏萃取方法鉴定了14种.     

广藿香挥发油提取新工艺的研究

采用正交实验研究广藿香挥发油的提取,得到了每种方法的最佳萃取条件,并比较了多种萃取广藿香挥发油的方法,结果为超临界CO2 萃取比超声辅助萃取和其他萃取方法无论在提取率上还是产品质量上都具有突出的优点,SFE 萃取广藿香挥发油的最佳工艺条件为:萃取压力28MP,萃取时间2h,萃取温度40℃,装料率70%.     

A comparative study of conventional and supercritical fluid extraction methods for the recovery of secondary metabolites from <Emphasis Type="Italic">Syzygium campanulatum</Emphasis> Korth

Syzygium campanulatum Korth is a plant, which is a rich source of secondary metabolites (especially flavanones, chalcone, and triterpenoids). In our present study, three conventional solvent extraction (CSE) techniques and supercritical fluid extraction (SFE) techniques were performed to achieve a maximum recovery of two flavanones, chalcone, and two triterpenoids from S. campanulatum leaves. Furthermore, a Box-Behnken design was constructed for the SFE technique using pressure, temperature, and particle size as independent variables, and yields of crude extract, individual and total secondary metabolites as the dependent variables. In the CSE procedure, twenty extracts were produced using ten different solvents and three techniques (maceration, soxhletion, and reflux). An enriched extract of five secondary metabolites was collected using n-hexane:methanol (1:1) soxhletion. Using food-grade ethanol as a modifier, the SFE methods produced a higher recovery (25.5%?84.9%) of selected secondary metabolites as compared to the CSE techniques (0.92%?66.00%).     

莪术挥发性组分的提取分析及抗氧化能力研究

应用超临界CO2萃取技术,采用正交实验法,对影响莪术挥发油萃取率大小的萃取压力、萃取温度和CO2流量3个因素进行了研究,最佳工艺为：萃取温度55℃、萃取压力25MPa,CO2流量30L／h,萃取率为8．44％;同时进行了水蒸气蒸馏,挥发油得率为2．31％。并对两种方法提取所得挥发油进行GC—MS成分分析,应用ABTS和FRAP法对两种方法提取莪术挥发组分的抗氧化能力进行了检测及比较,结果显示超临界CO2提取物的成分、得率不同,其抗氧化能力均强于水蒸汽法提取物。     

冠心苏合丸中挥发性成分分析

报道了采用同时蒸馏-萃取法提取冠心苏合丸中的挥发性组分,测得冠心苏合丸中的挥发性组分含量为14%.利用GC-MS方法对所获得的挥发性组分进行分析,通过G1701BA化学工作站检索NIST98谱图库,并结合标准谱图库和有关文献,从其挥发性组分中确定出14种化学成分,占冠心苏合丸中挥发性组分总检出量的97.27%.用峰面积归一化法通过化学工作站数据处理系统,得出各化学成分在挥发性组分中的相对百分含量.主要挥发性组分是冰片、异冰片和苯甲酸苄酯.并采用气相色谱法对冠心苏合丸中冰片的含量进行了测定.结果,冰片浓度在1.0～5.0 mg/mL范围内与冰片对内标物的色谱峰面积比值成良好的线性关系,冰片的平均回收率为101.2%.     

刺芫荽挥发性成分研究

以野生刺芫荽为原料,采用同时蒸馏萃取法提取其挥发性成分,应用气相色谱—质谱法对提取物进行化学成分分析.实验结果表明,野生刺芫荽提取物中共鉴定出24种化合物,占总峰面积的65.94％,质量分数达到1.00％以上的有6种物质,其挥发性成分中醛酮类化合物相对质量分数达到58.05％.     

催化剂对乙二胺萃取七台河煤的影响

采用乙二胺(C2H8N2)为萃取剂,分别添加FeS2、MgCl2,MgCl2-AlCl3 3种催化剂对七台河煤进行索氏萃取,对萃取物采用气相色谱/质谱联用技术定性分析,探究了不同的催化剂对七台河煤萃取效果的影响。实验结果表明,催化剂有助于提高萃取率,增加萃取出的化合物的种类。MS分析证明,不同的催化剂可以抽提出不同的化学结构的物质,采用Cl盐作催化剂有利于含氧化合物的抽提,而FeS2有助于提高含芳环物质的抽提率,特别是对蒽系物的萃取效果良好。由试验结果推断,在煤萃取的溶剂体系里加入铁系催化剂、硫化物、卤族元素的可溶盐以及Lewis酸都可大大提高萃取效率。     

番薯藤挥发性化学成分的分析

采用同时蒸馏萃取法对番薯藤幼苗和成熟番薯藤的挥发性成分进行了提取,用GC/MS方法对挥发性成分进行了鉴定,从幼番薯藤中鉴定了28种化学成分,从成熟的番薯藤中鉴定了26种成分,两者成分上有较大差异.     

A study revealing the key aroma compounds of steamed bread made by Chinese traditional sourdough

Aroma of Chinese steamed bread (CSB) is one of the important parameters that determines the overall quality attributes and consumer acceptance. However, the aroma profile of CSB still remains poorly understood, mainly because of relying on only a single method for aroma extraction in previous studies. Therefore, the objective of this study was to determine the volatile aroma compounds of five different samples of CSB using three different aroma extraction methods, namely solid-phase microextraction (SPME), simultaneous distillation-extraction (SDE), and purge and trap (P&T). All samples showed a unique aroma profile, which could be attributed to their unique microbial consortia. (E)-2-Nonenal and (E,E)-2,4-decadienal were the most prevalent aromatic compounds revealed by SDE, which have not been reported previously, while ethanol and acetic acid proved to be the most dominant compounds by both SPME and P&T. Our approach of combining three different aroma extraction methods provided better insights into the aroma profile of CSB, which had remained largely unknown in previous studies.     

蛇床子超临界CO2萃取成分GC-MS分析

以乙醚为改性剂,采用超临界CO2萃取法提取中药蛇床子的有效成分,并用GC／MS法对其化学成分和相对含量进行了分析．结果表明,与水蒸气蒸馏法比较,超临界CO2萃取法的产率较高,总萃取率为8．46％(w),蒸馏法提取蛇床子挥发油的产率较低,仅为1．01％(w);蛇床子超临界萃取物中香豆素类的相对含量约为67．63％,其蛇床子素相对含量占总香豆素的78．92％,而蒸馏法提取的挥发油中鉴定出一种香豆素成分,其相对含量仅为1．65％．因此,超临界CO2萃取法可以有效提取中药蛇床子的多种香豆素类成分,其方法为其他同类中药的开发和药学鉴定提供了参考依据．     

Analysis of volatile components in a Chinese fish sauce, Fuzhou Yulu, by gas chromatography-mass spectrometry

Volatile components of Fuzhou Yulu, a Chinese fish sauce, were analyzed by gas chromatography-mass spectrometry (GC-MS), and two pretreatment methods, i.e., purge and trap (P&T) GC-MS and ethyl acetate extraction followed by GC-MS, were compared. P&T-GC-MS method determined 12 components, including sulfur-containing constituents (such as dimethyl disulfide), nitrogen-containing constituents (such as pyrazine derivatives), aldehydes and ketones. Ethyl ace tate extraction fol-lowed by GC-MS method detected 10 components, which were mainly volatile organic acids (such as benzenepropanoic acid) and esters. Neither of the two methods detected alcohols or trimethylamine. This study offers an important reference to determine volatile flavor components of traditional fish sauce through modem analysis methods.     

提取方法、试剂对不同高等植物叶片叶绿素提取效果的比较分析

分别采用浸泡法和研磨法,比较分析了7种混合试剂对烟草、油菜和毛白杨叶片叶绿素的提取效果。结果表明,7种提取试剂采用研磨法对三种供试植物叶片叶绿素的提取效果均优于浸泡法,其中体积比为4.5∶4.5∶1的无水乙醇、丙酮和水的混合液研磨提取效果最好。     

烟草化学成分的气相色谱-质谱分析及尼古丁含量的测定

采用同时蒸馏萃取法与水蒸气蒸馏法提取烟草中挥发性成分并用气相色谱-质谱（GC/MS）法分别确认其化学成分,其中主要成分为尼古丁.用气相色谱法测定烟草中尼古丁的含量.尼古丁含量在0.446 4～0.892 8 mg/mL范围内与峰面积呈良好线性关系,回归方程为：A=61 670 M-2 894.8,相关系数为0.998 6,回收率为99.83%.     

两种方法提取生姜中挥发性化学成分的研究

报道了用水蒸汽蒸馏萃取法和同时蒸馏萃取法提取姜科植物生姜中的挥发性物质,并用气相色谱-质谱联用仪对其挥发性化学成分进行分析,分别分离并确定出28种和22种化学成分,分别占总挥发油总检出量的98．24％和97．99％。结果表明：生姜挥发油的主要化学成分是萜类化合物β-水芹烯、茨烯、冰片、柠檬醛、姜烯等．     

超声波萃取和酶解法提取大杯蕈多糖的比较

利用超声波萃取法(MAE)和酶解法提取大杯蕈粗多糖,确定了最优提取工艺条件为:料液比1:30,温度40℃,在功率500W的超声波下处理60min后获得最大的多糖得率为13.48%;而将料液比1:25的试样于80℃水浴下浸提时间1h后,再加入5%的果胶酶,在45℃、pH4.5的条件下酶解0.5h后,可获得19.08%的粗多糖。进一步将酶解法和MAE法及传统的热水浸提法进行比较,结果显示,酶解法优于MAE法和热水浸提法,是超声波法的1.4倍,热水浸提法的1.8倍,而提取时间却大大缩短了,该法具有高效、节能、省时的优点。     

超临界流体萃取在环境分析中的应用

超临界流体萃取技术是近年来国际上取得迅速发展的新兴分离技术，对治理环境应用前景广泛。文章对超临界流体萃取在环境分析申的应用作了阐述。     

不同方法提取客家药膳草药溪黄草的研究

研究了煎煮法和乙醇浸渍法提取客家药膳草药溪黄草的条件,通过感官评价及薄层色谱比较两种提取方法得到的提取物的成分,证明水煎煮法和乙醇热浸渍法提取溪黄草的得率、成分和口味均有明显不同。通过实验确定煎煮法为提取溪黄草制作药膳汤料的方法,其最优的提取条件为:加水量10倍,煎煮时间0.5 h,提取次数4次,此时得率为13.5%。     

牡丹皮挥发油成分分析

采用同时蒸馏萃取法提取牡丹皮中的挥发油,通过GC-MS对其化学成分进行分析.结果显示挥发油中含有20个化合物,鉴定出20个.挥发油中芍药醇含量最多,其次是油酸和棕榈酸.     

桑树DNJ提取、纯化和检测的研究进展

1-脱氧野尻霉素(1-deoxynojirimycin,DNJ)是存在于桑树中的一种多羟基哌啶生物碱,因其通过抑制α-葡萄糖苷酶活性,进而具有降血糖、抗病毒、抗肿瘤等生理活性和药理活性.DNJ广泛存在于桑树的各种组织中,不同桑树类型和品种中DNJ含量不同,采取的每一种提取、测定方法均具有选择性和特异性,只适用于某种类型或某种桑树品种样品的纯化和检测.同时,DNJ在桑树体内的含量较低,而且桑树体内其他次生代谢物质的干扰增加了DNJ提取和测定的难度.因此,目前文献中报道的DNJ提取、分离纯化和检测方法较多.针对已报道的DNJ的提取、分离纯化和检测方法,综述了近年来DNJ研究方面的最新进展,为更好利用和开发DNJ制品,为DNJ的工业化生产提供参考和借鉴.