蒙山名茶蒙顶甘露和蒙山毛峰特征香气成分的GC-MS测定与分析

采用同时蒸馏萃取法和气相色谱质谱（gas chromatography-mass spectrometry ， GC-MS）分析方法系统分析了蒙山茶原产地保护区域内蒙泉、后盐、陇西3个产地及保护区外合江产地蒙顶甘露和蒙山毛峰香气成分的特征与差异.结果表明，在鉴定的63种香气成分中，醇类和醛类占一半以上（59.16％～71.42％）.在蒙顶甘露和蒙山毛峰的香气组分中均以植醇、香叶醇、L-芳樟醇、壬醛和正庚醛这5个成分所占比例较高；保护区内蒙顶甘露和蒙山毛峰最重要的香气特征是植醇和壬醛含量显著高于保护区外，其总量分别占保护区中心内甘露的29.95％和毛峰的40％、保护区外甘露的0％和毛峰的11.27％，同时也是区别于其他名优绿茶的最主要的香气成分.由保护区中心向外延伸，蒙顶甘露和蒙山毛峰的香型有相似的变化规律：由保护区中心的板栗香型经中间的铃兰类鲜爽花香型逐渐过渡至边沿的蜜糖香、花香型.总体上，原产地保护区域内蒙顶甘露和蒙山毛峰的香气品质优于其他非原产地保护区域的蒙顶甘露和蒙山毛峰.

广西八角挥发油的提取研究与GC-MS分析

In this paper,the Illilium verum Hook.f.grow at mountain of Dayao of Jinxiu in Guangxi,Volatile oil was extracted by soxhet method and steam distillation.All the volatile oil was analyzed by GC-MS,the result show the ingredients and rate of product were change greatly,The major chemical constituents were trans-anethole,estragole and anisaldehyde etc.

藏药甘肃蚤缀脂溶性成分的GC-MS分析

研究藏药甘肃蚤缀的脂溶性成分,进一步揭示该药材的化学成分,为这一传统藏药资源的开发利用提供实验依据。采用95%乙醇回流提取甘肃蚤缀全草,滤液浓缩后用石油醚萃取,得到脂溶性部位,通过气相色谱-质谱联用技术分析其化学成分,结合计算机检索技术及美国国家标准技术研究所(NIST)化合物谱库检索进行鉴定,采用面积归一化法确定其相对含量。从甘肃蚤缀石油醚部位共分离鉴定出25个化合物,相对含量占总含量的91.31%,包括脂肪类、甾体、三萜及芳香化合物等。

基于GC-FID、HS-SPME-GC-MS与电子鼻技术评价不同水果发酵酒的香气特征

采用气相色谱-氢火焰离子化检测器法(gas chromatography with hydrogen flame ionization detection,GCFID)、顶空固相微萃取-气相色谱-质谱(headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry,HS-SPME-GC-MS)和电子鼻技术分析6种果酒中的挥发性成分,评价果酒风味轮廓特征的差异性。结果表明,GC-FID定量测定樱桃李酒,其中异戊醇、活性戊醇、β-苯乙醇含量最高,乙酸乙酯含量最低;木瓜酒中正丙醇、2,3-丁二醇、癸酸乙酯、乙酸含量最高; 3-羟基-2-丁酮含量在樱桃李酒中最高,山楂酒、甜橙酒中最少。HP-SPME-GC-MS鉴定果酒中挥发性物质94种,其中醇类23种,酯类43种,醛酮类10种,酸类8种,酚类2种,苯环类5种,烷烃类3种。山楂酒、菠萝酒、木瓜酒、甜橙酒、无花果酒和樱桃李酒中香气物质数量分别为34、44、45、45、33、47种。其中山楂酒、木瓜酒和无花果酒中未检出酚类、烷烃类物质。电子鼻对不同果酒香气的区分效果无重叠,W5S传感器区分果酒香气能力最强。比较而言,菠萝酒和樱桃李酒的口感更圆润,香气更愉悦,感官得分最高。

福建姜黄挥发油化学成分的HS-SPME-GC-MS分析

采用水蒸气蒸馏法提取福建姜黄挥发油,应用顶空固相微萃取进样结合气相色谱-串联质谱联用技术(HS-SPME-GC-MS)分析姜黄挥发油的化学成分。结果表明:姜黄挥发油含有量为7.2%(mL/g),从姜黄挥发油中共分出62个色谱峰,初步鉴定出了其中的51种化学成分,占总挥发油总量的98.41%。在鉴定的化合物中,主要为单萜类化合物和倍半萜类化合物,其中新发现一种主要成分为β-柏木烯,相对含量占比高达26.58%,这可作为福建姜黄挥发油的特征成分和主要品质指标。本研究结果将为福建姜黄植物药材的品质评价提供科学依据。

GC-MS法测定黄酒和食用酒精中的氨基甲酸乙酯

建立应用气相色谱-质谱联用法(gas chromatography-mass spectrometry,GC-MS)快速测定黄酒和食用酒精中氨基甲酸乙酯(ethylcarbamate,EC)的分析方法。以黄酒和食用酒精为研究对象,样品经过碱性硅藻土固相萃取柱净化、浓缩后,用GC-MS进行测定,同位素内标法定量。氨基甲酸乙酯在10~600μg/L线性关系良好,相关系数r^2=0.999 3。加标水平为5、100、250μg/kg 3个浓度条件下,在黄酒中的加标回收率为81.2%~89.5%,每个加标水平测定6次的相对标准偏差(RSD)为3.7%~5.0%;在食用酒精中的加标回收率为91.2%~99.4%,每个加标水平测定6次的RSD为3.1%~4.1%。方法的检出限为1.0μg/kg,方法的定量限为3.0μg/kg。该方法定量准确、操作简便、灵敏度高,适用于黄酒和食用酒精中氨基甲酸乙酯的测定。

Identification and Characterization of Sulfur Compounds in Straight-Run Diesel Using Comprehensive Two-Dimensional GC Coupled with TOF MS

The solid-phase extraction using Pd-Al2O3 as the stationary phase was employed to pre-separate the sulfur compounds in straight-run diesel. The isolating effect was evaluated quantitatively by gas chromatography with a sulfur chemiluminescence detector to harvest a satisfactory result. The identification of the structure of sulfur compounds by comprehensive two-dimensional gas chromatography coupled with the time-of-flight mass spectrometry indicated that cyclo-sulfides, benzothiophenes, dibenzothiophenes, dihydro-benzothiophenes and tetrahydro-dibenzothiophenes were included in straightrun diesel obtained from the Arab medium crude(AM). A total of 259 individual compounds were detected and their molecular structures were identified. The analytical method was approved as an effective way to characterize the composition of sulfur compounds, which reduced the interference of other compounds, facilitated the data presentation and provided more detailed information about molecular composition of sulfur compounds.

Determination of Aromatic Components of Rosa davurica Pall. by Headspace Solid Phase Microextraction Combined with GC-MS

[Objectives] To determine the aromatic components of Rosa davurica Pall. [Methods] 42 kinds of aromatic components were identified from the flowers of R. davurica by headspace solid phase microextraction( HS-SPME) combined with gas chromatography-mass spectrometry( GC-MS). The main compounds were alcohols( 54. 88%) and aldehydes( 19. 55%). [Results] The top five components with the highest relative content were phenylethyl alcohol( 12. 69%),geraniol( 9. 85%),citronellol( 8. 80%),nerol( 7. 84%) and 2-n-pentylfuran( 7. 45%). [Conclusions] Headspace solid phase microextraction( HS-SPME) combined with gas chromatography-mass spectrometry( GC-MS) can provide basis for further development and utilization of R. davurica.

Rapid and simultaneous determination of ten off-flavor compounds in water by headspace solid phase microextraction and gas chromatography-mass spectrometry

A simple and sensitive analytical procedure for the determination of multi-component compounds in water samples was developed and optimized using the headspace solid-phase microextraction(HSSPME) coupled with gas chromatography-mass spectrometry(GC-MS). Ten off-flavor compounds, including geosmin(GSM), 2-methylisoborneol(2-MIB), 2-isopropyl-3-methoxypyrazine(IPMP), 2-isobutyl-3-methoxypyrazine(IBMP), β-ionone, trans-2,cis-6-nonadienal(NDE), 2,3,4-trichloroanisole(2,3,4-TCA), 2,3,6-trichroloanisole(2,3,6-TCA), 2,4,6-trichloroanisole(2,4,6-TCA), and 2,4,6-tribromoanisole(2,4,6-TBA) were used as the target analytes. The optimization of extraction parameters including fibers types, extraction time, extraction temperature, stirring rate, sample volume, and ionic strength was carried out through the univariate approach. Ten off-flavor compounds were quantified within 50 min under the optimal conditions. Calibration curves with good linearity(r^2=0.990-0.998) were obtained in the range 1.0/2.0-100 ng/L, while the limits of detection for all compounds were lower than or close to the odor threshold concentration. Furthermore, the proposed method was applied to analyzing and determining the off-flavor compounds in real water samples from water-treatment plants.

Studies on the Components of Essential Oil of <i>Zanthoxylum Armatum</i>by Gc-Ms

The essential oil of Zanthoxylum armatum was extracted through hydro distillation and analyzed by GC-MS. Hydrocarbon fraction (17.35%) of the oil was much lower and oxygenated compounds comprised fairly high portion of essential oil (39.21%). Percentages of monoterpenes and sesquiterpenes found were 47.33% and 10.83% respectively. Oxygenated monoterpenes comprised major profile of chromatogram of essential oil of Zanthoxylum armatum i.e. 37.23% where as monoterpene hydrocarbons were 10.09%. Alcoholic percentage was much higher i.e. 26.76% and 15-hexadecanoloide (6.58%) the only cyclic ester was found in relatively high percentage.

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 acetate 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.

GC-MS Analysis and Antibacterial Activity Study of Volatile Oil from 11 Kinds of Aurantii Fructus Immaturus Processed Products

[Objectives]To study the volatile components and antibacterial effects of 11 kinds of Aurantii Fructus Immaturus processed products.[Methods]11 kinds of Aurantii Fructus Immaturus processed products were obtained according to the traditional processing method,the volatile oil was extracted by steam distillation,and the composition of volatile oil in the 11 kinds of processed products was analyzed by gas chromatography-mass spectrometry(GC-MS).the relative percentage content of each component in these 11 kinds of processed products was determined using the peak area normalization.The drug sensitivity activity of the volatile oil of these 11 kinds of processed products was tested using the K-B paper diffusion method and the minimum inhibition volume fraction of volatile oil of these 11 kinds of processed products was tested using the microdilution method.[Results]The highest yield of volatile oil of 11 kinds of these processed products was baking(5.193%),and the lowest was stir-bake to scorch(1.998%).A total of 36 chemical components were identified from the volatile oils of these 11 kinds of processed products.The components with the most volatile oil were stir-bake to scorch(24 kinds),and the components with the least volatile oil were the method of processing with rice-washed water(15 kinds).They contain 8 kinds of common chemical components,such as limonene,linalool,myrcene,α-pinene.The highest content of limonene came from processing with honey(60.93%),the lowest came from processing with rice-washed water(55.25%);the highest content of linalool came from processing with rice-washed water(7.139%),the lowest came from processing with honey(5.436%);the highest content of myrcene came from processing with honey(1.899%),the lowest came from stir-bake to scorch(1.632%);the highest content ofα-pinene came from raw Aurantii Fructus Immaturus(2.355%),and the lowest came from stir-bake to scorch(1.618%).The volatile oil of these 11 kinds of Aurantii Fructus Immaturus processed products has good antibacterial effect on Escherichia coli and Staphylococcus aureus.[Conclusions]The oil yields of volatile oils of 11 kinds of Aurantii Fructus Immaturus processed products are different,the content of limonene is significantly different,and the changes of other chemical components and their contents are not significantly different.The volatile oil of 11 kinds of Aurantii Fructus Immaturus processed products has certain antibacterial effect.

Analysis of the Volatile Components of Polygonum chinense L.Extracted with Different Solvents by GC-MS

[Objectives]This study was conducted to investigate the volatile components of Polygonum chinense L.[Methods]The volatile components of the methanol extract,ethyl acetate extract,chloroform extract and petroleum ether extract of P.chinense were analyzed and determined by gas chromatography.[Results]The volatile components of the methanol extract from P.chinense were the most,and phenolic acids and ketones accounted for a relatively high proportion,among which pyrogallic acid had the highest content.The ethyl acetate extract contained the second most volatile components,mostly acids and esters,of whichβ-sitosterol had the highest content;the chloroform and petroleum ether extracts had relatively few types of volatile components,most of which were alkanes,and the content ofγ-sitosterol shared by the two was the highest.The common substances of the four extracts were palmitic acid and phytol.[Conclusions]This study provides a theoretical basis for the quality evaluation of P.chinense and a scientific basis for its resource development.

Direct Determination of Polychlorinated-Biphenyls in Automotive Shredder Residues by Gas Chromatography-Mass Spectrometry

An easy and rapid method is proposed for the determination of PCBs in automotive shredder residues, using gas chromatography combined with low resolution mass spectrometry (GC-MS). It is based on direct n-hexane solid-liquid extraction, subtracting background of the lineal aliphatic hydrocarbon interferences and integration of chromatographic peaks containing selected ion PCBs masses (256, 292 and 326 m/z), which are common in all PCBs formulations. Recoveries were in the 80% - 120% range;PCBs were detected and quantified in shredder samples from an automotive shredder industry, thus indicating the validity of the method.

Rapid on-site identification of hazardous organic compounds at fire scenes using person-portable gas chromatography-mass spectrometry(GC-MS)—part 1:air sampling and analysis

Recent advancements in person-portable instrumentation have resulted in the potential to provide contemporaneous results through rapid in-field analyses.These technologies can be utilised in emergency response scenarios to aid first responders in appropriate site risk assessment and management.Large metropolitan fires can pose great risk to human and environmental health due to the rapid release of hazardous compounds into the atmosphere.Understanding the release of these hazardous organics is critical in understanding their associated risks.Person-portable gas chromatography-mass spectrometry(GC-MS)was evaluated for its potential to provide rapid on-site analysis for real-time monitoring of hazardous organic compounds at fire scenes.Air sampling and analysis methods were developed for scenes of this nature.Controlled field testing demonstrated that the portable GC-MS was able to provide preliminary analytical results on the volatile organic compounds present in air samples collected from both active and extinguished fires.In-field results were confirmed using conventional laboratory-based air sampling and analysis procedures.The deployment of portable instrumentation could provide first responders with a rapid on-site assessment tool for the appropriate management of scenes,thereby ensuring environmental and human health is proactively protected and scientifically informed decisions are made for the provision of timely advice to stakeholders.

Comparison of geochemical parameters derived from comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry and conventional gas chromatography-mass spectrometry

The saturated and aromatic hydrocarbon fractions of crude oil samples have been analyzed by using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry （GCxGC-TOFMS） and conventional gas chro- matography-mass spectrometry （GC-MS）. In order to investigate the consistency and discrepancy of the obtained data from the two instruments, some petroleum geochemical parameters have been compared. A comparison of 23 geochemical parameters indicates that 10 parameters are comparable from the two instruments with less than 5% deviations. Therefore, GCxGC-TOFMS is equivalent to conventional GC-MS in some geochemical parameter acquisitions. However, the other 13 parameters are discrepant, including gammacerane / αβ-hopane, Ts/Tm, 2-ethyl-naphthalene / 1-ethyl-naphthalene （ENR）, （2, 6-dimethyl-naphthalene ＋2,7-dimethyl-naphthalene） / 1,5-dimethyl-naphthalene （DNR）, etc. Furthermore, compared to GCxGC-TOFMS, some low concentration compounds could not be detected by the conventional GC-MS, which results in the missing of related geochemical data. Normally, this is caused by the limited separation power and peak capacity of the conventional GC column. Besides, the co-eluting peak integrations are also affected significantly due to the incomplete separation of the compounds. Some low concentration compounds might not be detected because of the interference from the baseline noise or from other substances. GCxGC-TOFMS prevails in compound separation against the conventional GC-MS by avoiding co-elution, which achieves more accurate and precise peak area measurement with the presence of a true baseline. So petroleum geochemical parameters obtained from the GCxGC-TOFMS GCxGC-TOFMS may become one of the most effective analytical are more reliable than those from the conventional GC-MS tools for the oil and gas geochemical study.

Identification of the toxic compounds produced by Sargassum thunbergii to red tide microalgae

The inhibitory effects of methanol extracts from the tissues of three macroalgal species on the growths of three marine red tide microalgae were assessed under laboratory conditions.Extracts of Sargassum thunbergii(Mertens ex Roth) Kuntz tissue had stronger inhibitory effects than those of either Sargassum pallidum(Turner) C.Agardh or Sargassum kjellmanianum Yendo on the growths of Heterosigma akashiwo(Hada) Hada,Skeletonema costatum(Grev.) Grev,and Prorocentrum micans Ehrenberg.Methanol extracts of S.thunbergii were further divided into petroleum ether,ethyl acetate,butanol,and distilled water phases by liquid-liquid fractionation.The petroleum ether and ethyl acetate fractions had strong algicidal effects on the microalgae.Gas chromatography-mass spectrometry analyses of these two phases identified nine fatty acids,most of which were unsaturated fatty acids.In addition,pure compounds of four of the nine unsaturated fatty acids had effective concentrations below 5 mg/L.Therefore,unsaturated fatty acids are a component of the allelochemicals in S.thunbergii tissue.

A GC×GC-ToFMS Investigation of the Unresolved Complex Mixture and Associated Biomarkers in Biodegraded Petroleum

Heavy biodegraded crude oils have larger numbers of coeluting compounds than nonbiodegraded oils, and they are typically not resolved with conventional gas chromatography（GC）. This unresolved complex mixture（UCM） has been investigated using comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry（GC×GC-To FMS） within a set of biodegraded petroleums derived from distinct sedimentary basins, including northwestern Sichuan（Neoproterozoic, marine）, Tarim（Early Paleozoic, marine）, Bohai Bay（Eocene, saline/brackish） and Pearl River Mouth（Eocene, freshwater）. In general, the hydrocarbons that constitute the UCM in petroleum saturate fractions can be classified into three catalogues based on the distributions of resolved compounds on two dimensional chromatograms. Group 1 is composed mainly of normal and branched alkanes, isoprenoid alkanes and monocyclic alkanes; Group 2 comprises primarily terpanes ranging from two to five rings, and Group 3 is dominated by monoaromatic hydrocarbons such as tetralins and monoaromatic steranes. In addition, the UCM is source dependent and varies between oil populations. i.e., the UCM of petroleum derived from Precambrian and Early Paleozoic marine, Eocene saline/brackish and freshwater source rocks is specifically rich in higher homologues of A-norsteranes, series of 1,1,3-trimethyl-2-alkylcyclohexanes（carotenoid-derived alkanes）, and tetralin and indane compounds, respectively.

Evaluation of Pesticide Residues in Mango by a Multi-residue Analysis and GC/MS Triple Quadrupole

Mango fruit has a great national and international market, and Brazilian production is 1,900 thousand tons/year exporting to North America and Europe. However, the loss could occur during the production when it is affected by pests and climate conditions, so the increased use of chemical substances and their presence should be monitored. A task for governmental agencies, producers and food sales, attending the sanitary barriers requirements, is to distribute food free from contaminants, so laboratories involved in this type of work usually employ multi-residues analysis. The objective of this study was to evaluate the presence of pesticide residues in mango using QuEChERS method and mass spectrometry technique. Positive samples were compared with Brazilian maximum residues level （MRL） and the health risk exposure was evaluated using the acute dietary intake （ADI） parameter. A total of 20 samples were collected from January to March, in Sao Paulo city markets. The recoveries were in the range of 70% to 120%, and standard deviation was below 20%. The category of pesticides not permitted for the crop were found in l0 samples; eight samples presented pesticides below MRL and two samples above MRL for the fungicide procloraz. The ADI values were below 20% of ADI for an adult and the worst case was dimethoate with 69% of ADI for children. The time spent in monitoring studies and the viability of method chosen must be considered by pesticide residues laboratories during routine analysis of food quality control.

Analysis of aroma-active compounds in three sweet osmanthus(Osmanthus fragrans) cultivars by GC-olfactometry and GC-MS

Objective：Aroma is the core factor in aromatherapy. Sensory evaluation of aromas differed among three sweet osmanthus （Osmanthus fragrans） cultivar groups. The purpose of this study was to investigate the aroma-active compounds responsible for these differences. Methods： Gas chromatography-olfactometry （GC-O） and GC-mass spectrometry （GC-MS） were used to analyze the aroma-active compounds and volatiles of creamy-white （‘Houban Yingui’, HBYG）, yellow （‘Liuye Jingui’, LYJG）, and orange （‘Gecheng Dangui’, GCDG） cultivars. Results：Seventeen aroma-active compounds were detected among 54 volatiles. trans-β-Ocimene, trans-β-ionone, and linalool, which were major volatiles, were identified as aroma-active, while cis-3-hexenyl butanoate,γ-terpinene, and hexyl butanoate were also aroma-active compounds, although their contents were low. Analysis of the odors was based on the sum of the modified frequency （MF） values of aroma-active compounds in different odor groups. HBYG contained more herb odors, contributed by cis-β-ocimene and trans-β-ocimene, while LYJG had more woody/violet/fruity odors released by trans-β-ionone, α-ionone, and hexyl butanoate. In GCDG, the more floral odors were the result of cis-linalool oxide, trans-linalool oxide, and linalool. Conclusions：Aroma-active compounds were not necessarily only the major volatiles：some volatiles with low content also contributed to aroma. The aroma differences among the three cultivars resulted from variation in the content of different odor groups and in the intensities of aroma-active compounds.