柴胡超临界二氧化碳萃取物化学成分气相-质谱联用分析

目的 :研究柴胡超临界 CO2 萃取物的化学成分。方法 :应用气 /质联用技术对柴胡超临界 CO2 萃取物进行分析。结果 :从萃取物中分离并鉴定出 11种化合物 ,其中主要组分为饱和及不饱和脂肪酸 ,含量占气化产物总量的 96 .2 %。结论 :本研究为柴胡的开发利用提供了实验依据。

麻黄蜜炙前后挥发性化学成分的气相-质谱联用分析

目的:分析麻黄蜜炙前后挥发性化学成分的变化。方法:采用传统的水蒸气蒸馏法与现代的超临界二氧化碳流体萃取(SFE)技术提取麻黄及其蜜炙品中的挥发油,并应用气质联用技术分析两种提取方法提取的挥发性化学成分。结果:两种提取方法提取的挥发性成分明显不同,水蒸气蒸馏法提取的挥发油多为低沸点成分,而超临界二氧化碳流体萃取的挥发油高沸点成分较多;蜜炙前后挥发性成分也有明显差异。结论:水蒸气蒸馏法与超临界CO2萃取两种方法相结合才能全面地反映挥发性成分的组成;蜜炙后低沸点成分变化较大,为研究古人炮制意图提供了一个新的实验依据。

2个石斛品种不同花器官香气成分分析

【目的】对比2种石斛花香成分的差异及其主要香气成分,为培育香型石斛新品种提供科学依据。【方法】以浓香型紫瓣石斛和清香型珍珠石斛为试验材料,采用顶空固相微萃取结合气相色谱—质谱联用(HS-SPME-GC-MS)技术对不同花朵部位(萼片、唇瓣、花瓣和蕊柱)的香气成分种类及相对含量进行分析。【结果】2种石斛检测到7类、96种挥发性成分,共有成分仅4种(正己醇、4,7-二甲基-4-辛醇、反式-2-辛烯-1-醇和己醛)。紫瓣石斛4个花器官中共检测到37种挥发性化合物,包括醛类11种、酮类8种、烯类5种、醇类4种、酯类4种、烷类2种及其他类3种,共有成分14种;萼片主要成分是己醛(28.09%)、反式-2-壬烯醛(14.00%)和2-十五烷酮(13.66%),花瓣主要成分是己醛(24.50%)、反式-2-辛烯醛(13.23%)和2-戊基呋喃(12.69%),唇瓣主要成分是2-十五烷酮(29.04%)、2-十三酮(12.71%)和己醛(10.48%),蕊柱主要成分与唇瓣相同,含量有所差异;化合物中2-十五烷酮、己醛和反式-2-辛烯醛相对含量较高,香味浓郁。珍珠石斛4个花器官中共检测到63种挥发性化合物,包括烯类26种、醇类15种、酯类7种、烷类3种、酮类4种、醛类2种及其他类6种,共有成分11种;其中烯类相对含量最高,烯类以D-柠檬烯、γ-松油烯、石竹烯和β-月桂烯为主,香味清甜;花瓣主要成分是D-柠檬烯(20.04%)、正己醇(12.56%)和石竹烯(10.93%),萼片主要成分是D-柠檬烯(40.60%)、β-月桂烯(7.81%)和3-蒈烯(7.63%),唇瓣主要成分是D-柠檬烯(22.92%)、1,3,3-三甲基-三环[2.2.1.0(2,6)]庚烷(18.99%)和(Z)-3,7-二甲基-1,3,6-十八烷三烯(10.92%),蕊柱主要成分为D-柠檬烯(48.59%)、α-蒎烯(12.62%)和β-月桂烯(11.75%)。【结论】紫瓣石斛和珍珠石斛挥发性成分数量及相对含量存在明显差异,香气成分组成较复杂;2-十五烷酮是紫瓣石斛花器官的主要香气物质,D-柠檬烯是珍珠石斛花器官的主要香气物质。

Chemical Compositions of Volatile Oil from Fruiting Body of Armillaria luteo-virens

The chemical compositions of volatile oil from fruiting body of Armillaria luteo-virens in Qinghai Province were firstly analyzed with GC-MS and its relevant compositions were detected by calculating chromatographic peak area with normalized method. 21 peaks were separated and 13 compositions were identified which were mainly unsaturated fatty acids, taking 97.1% of the total volatile oil.

Supercritical Fluid Extraction of Essential Oil from Dry Rhizome of Ligusticum chuanxiong Hort and Their Characterization by GC/MS

Supercritical fluid extraction (SFE) of essential oil from dry rhizome ofLigusticum chuanxiong Hort was developed. GC/MS was used for the determination of the composition ofessential oil. Forty-four compounds were identified. The conventional extraction method wasconducted in parallel for comparison. The extracts were qualitatively compared by GC/MS. The yieldsof SFE and steam distillation-extraction were 4.16 % ( v/w) and 0.8 % ( v/w), respectively.Application of SFE of zessential oil from dry rhizome of Ligustiaan chuanxiong Hort was preferable.

Analysis for the Volatile Secondary Metabolites of Mortierella alpina

[ Objective] The study was to investigate the volatile components of secondary metabolites from M. alpine producing arachidonic acid and explore the changes in its metabolic pathway. [ Method] The air above M. alpine broth was extracted by solid-phase microextraction（SPME） during the post-exponential phase of growth and analyzed by GC-MS. [Result] 13 compounds were identified, 12 of which were sesquiterpenes with C15H24 formula and accounting for 99.62% of the complete compounds. Thujopsene-（ 12）, α-Guaiene and Aristolene were three most sesquiterpenes accounting for 10.66%, 33.69% and 34.85% of total content respectively. It can be sufficiently certified that sesquiterpene metabolic pathway existing in M. alpine. [ Coclusion] Metabolic flux of sesquiterpene pathway increased to improve its mass accumulation, because one or several key enzyme genes mutation in isoprene or sesquiterpene pathway enhanced their activities during induction of mutation from initial strain.

Leaf Volatiles Induced by Mechanical Damage from Diverse Taxonomic Tree Species

Plant volatiles induced by wounding play key roles in plant-insect and plant-plant interactions. To deeply understand the mechanism of their induction by wounding and their functions in interplant communications, four diverse tree species: ashleaf maples ( Acer negundo L.), hankow willow (Salix matsudana Koidz.), Chinese white poplar ( Populus tomentosa Carr.) and poplar opera 8277 (P. simonii x P. pyramibalis cv.), were used as materials. The blends of volatiles collected after damage were detected with GCMS. Most of the induced compounds reach high concentrations in 5 h. They are acyclic monoterpenes, fatty acid derivatives, and aromatic compounds. To authors' knowledge, dimethyl adipate, diisobutyl succinate and benthothiazole have never been reported in previous herbivore insect-plant systems, After being damaged 2 h, green leaf volatiles were released in large amount. The repellents were detected in higher concentration after 24 h. The time of releasing is different within different species, but many kinds of volatiles widely existed in different trees. There were some difference among species. Health ashleaf maple released more terpenoids, but poplars and willow produced more aromatic compounds.

Identification and quality evaluation of Lepidium meyenii. (Maca) based on gas chromatographic analysis of its essential oils from roots

Lepidium meyeniiWalp. （Maca）, a perennial herbaceous plant with narrow distdbution in the Andean region, was cultivated by local residents as early as 1600 B.C. It has high nutritional values and multiple medicinal effects. In recent years the plant source of Maca has been greatly scarce since Maca products are increasingly becoming popular in the world. This makes the study urgent on the identification and quality evaluation of Maca materials. In present work, four Mace samples of different origins or handlings and three other natural plants, including radish, odental ginseng and American ginseng, were investigated. Their essential oils （steam distillates） of the hypogeal parts were weighed and analyzed by GC/MS. Through comparison of the characteristics of their chromatograms, it was found that the essential oil of Maca had unique GC/MS behaviors, and the characteristic peaks produced by the major essential oil components （Phenylacetonitrile, Benzaldehyde, 3-Methoxyphenylacetonitrile, etc） were distinct. Furthermore, the chromatograms of several Maca samples showed a similar qualitative pattern except for some differences in the quantitative composition, and the percentage of total essential oils in the samples varied from 0.88 % to 1.59 %. These behaviors and technologies can be applied to the identification of Maca materials in the markets and be a supplement to assess the quality of Maca matedals.

Simultaneous Determination of 8 Pesticide Residues in Green Tea Based on Gas Chromatography-mass Spectrometry

To improve pesticide residues detection efficiency in tea, simultaneous de- termination of eight pesticide residues in green tea was developed based on gas chromatography-mass spectrometry （GC-MS）. The results showed that, - detected by the GC-MS under following conditions： acetonitrile as extraction and elution solvent, activated carbon and PSA tandem column as the stationary phase, elution volume of 12 ml the relationship between peak area and concentration of each residue （ametryn in the range of 0-100 pg/L, napropamide in the range of 0-10 000 gg/L, other pesticides in the range of 0-1 000 tJg/L） were linearly related, and their corre- lation coefficients were all greater than 0.999. The recovery rate the pesticides added to tea sample at legal concentration limits ranged from 73.6% to 116.8%, and the relative standard deviation from 1.47% to 15.58%. The new method we de- veloped is sensitive, specific and anti-interference, and thus provides test basis for the development of pesticide matrix reference materials in tea.

Discrimination of Acori Tatarinowii Rhizoma from two habitats based on GC-MS fingerprinting and LASSO-PLS-DA

This study is intended to explore the chemical differences of Acori Tatarinowii Rhizoma （ATR） samples collected from two habitats, Sichuan and Anhui provinces, China. Gas chromatography-mass spectrometry （GC-MS） was applied to establishing the quantitative chemical fingerprints of ATRs. A total of 104 volatile compounds were identified and quantified with the information of mass spectra and retention index （RI）. Furthermore, least absolute shrinkage and selection operator （LASSO）, a sparse regularization method, combined with subsampling was employed to improve the classification ability of partial least squares-discriminant analysis （PLS-DA）. After variable selection by LASSO, three chemical markers,β-elemene, α-selinene and α-asarone, were identified for the discrimination of ATRs from two habitats, and the total classification correct rate was increased from 82.76% to 96.55%. The proposed LASSO-PLS-DA method can serve as an efficient strategy for screening marked chemical components and geo-herbalism research of traditional Chinese medicines.

Diethylstilbestrol in Fish Tissue Determined Through Subcritical Fluid Extraction and with GC-MS

As the key point in sex hormone analysis, sample pre-treatment technology has attracted scientists' attention all over the world, and the development trend of sample preparation forwarded to faster and more efficient technologies. Taking economic and environmental concerns into account, subcritical fluid extraction as a faster and more efficient method has stood out as a sample pre-treatment technology. This new extraction technology can overcome the shortcomings of supercritical fluid and achieve higher extraction efficiency at relatively low pressures and temperatures. In this experiment, a simple, sensitive and efficient method has been developed for the determination of diethylstilbestrol(DES) in fish tissue using subcritical 1,1,1,2-tetrafluoroethane(R134a) extraction in combination with gas chromatography-mass spectrometry(GC-MS). After extraction, freezing-lipid filtration was utilized to remove fatty co-extract. Further purification steps were performed with C_(18) and NH_2 solid phase extraction(SPE). Finally, the analyte was derived by heptafluorobutyric anhydride(HFBA), followed by GC-MS analysis. Response surface methodology(RSM) was employed to optimizing the extraction condition, and the optimized was as follows: extraction pressure, 4.3 MPa; extraction temperature, 26℃; amount of co-solvent volume, 4.7 m L. Under this condition, at a spiked level of 1, 5, 10 μg kg^(-1), the mean recovery of DES was more than 90% with relative standard deviations(RSDs) less than 10%. Finally, the developed method has been successfully used to analyzing the real samples.

Determination of brominated diphenyl ethers in atmospheric particulate matter using selective pressurized liquid extraction and gas chromatography–mass spectrometry with a negative chemical ionization

This study describes the development and validation of a sensitive and reliable method for determination of polybrominated diphenyl ethers（PBDEs）in atmospheric particulate matter using selective pressurized liquid extraction（SPLE）and gas chromatography–mass spectrometry with a negative chemical ionization（GC-NCI-MS）.Extraction and clean-up were performed using PLE with 2 g florisil and 3 g silica placed in the extraction cells.Under optimal conditions,14 PBDEs were extracted at 70℃ using hexane/dichloromethane（50：50,v/v）as solvent.Validation of SPLE returned excellent recoveries for most analytes,with relative standard deviations mostly below20%.Method detection limits ranged from 0.13 to15.38 ng·mL^-1 for the GC-MS analyses.The method was successfully applied to atmospheric particulate matter of Beijing,where analytes were detected in the range of182.79 to 468.99 pg·m^-3.

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.

Lipid Oxidation and Fatty Acid Composition in Salt-Dried Yellow Croaker(Pseudosciaena polyactis) During Processing

Lipid oxidation in salt-dried yellow croaker(Pseudosciaena polyactis) was evaluated during processing with commonly used analytical indices, such as the peroxide value(POV), the thiobarbituric acid reactive substances(TBARS) value, and oxidative-relative lipoxygenase(LOX) activity. Additionally, fatty acids were analyzed using gas chromatography-mass spectrometry. Both POV and TBARS increased significantly(P < 0.05) at the rinsing stage. POV reached its peak value of 3.63 meq O_2 per kg sample at the drying stage, whereas TBARS constantly increased from 0.05 to 0.20 mg MDA per kg sample. Processing of salt-dried yellow croaker had an extremely significant(P < 0.01) effect on LOX activity. Twenty-six fatty acids were identified. Combined eicosapentaenoic acid(EPA; C20:5n3) and docosahexaenoic acid(DHA; C22:6n3) content varied between(19.20 ±0.37) mg g^(-1) and(23.45 ± 1.05) mg g^(-1). The polyunsaturated fatty acid/saturated fatty acid(PUFA/SFA) ratio in yellow croaker was 0.73–1.10, and the n-6/n-3 PUFA ratio was approximately 0.13–0.20. The contents of most fatty acids varied significantly(P <0.05) during the different processing stages, and these differences were caused by lipid oxidation. C18:0, C16:1n7, C19:0, and C22:6n3 showed clear changes in principle component one of a principle components analysis. These fatty acids are potential markers for evaluating lipid oxidation in fish muscle because there was a significant correlation between these markers and TBARS and LOX activity(P < 0.05) with Pearson's coefficients > 0.931.

Translocation of Pesticide Residues in Tomato, Mango and Pineapple Fruits

Pesticide residues in fruit and vegetables have become a major concern associated with chemical food safety issues. Translocation of pesticides in tomato, mango and pineapple fruits in locally produced samples was investigated using gas chromatography/mass spectrophotometer （GC/MS） procedures. Samples were fractionated with respect to distance from the skin to the core and prepared for analysis. Results showed that organochlorine, organophosphate and synthetic pyrethroid residues were translocated in all fruit samples analyzed. With respect to tomato fractions, the peels retained more residues compared to the pulp and the central core. In the chemical species, organochlorines were retained more in the peels of tomato than the other fractions of the fruit. More organophosphate and organochlorine residues were detected in pineapple peels compared to the pulp. Synthetic pyrethroid residues were evenly distributed in the pineapple fruit. In mangoes, the pulp retained more chemical residues than other fractions of the fruit. More organochlorine residues were retained in the pulp of mango than in the other fractions of the fruit. Synthetic pyrethroid residues were evenly distributed throughout the mango fruit. All the chemical species identified were translocatable across the fractional parts of all the fruits. There were significant differences in translocation and residue accumulation of pesticides among the fractional parts of all samples.

Assessment of Triazine Herbicides in Soil by Microwave-assisted Extraction Followed by Gas Chromatography Coupled to Mass Spectrometry Detection

An alternative and fast method for the analysis of a mixture of nine triazines herbicides in soil is presented. The method is based on MAE （microwave-assisted extraction） of herbicides using ethyl acetate as extractant. The economy in the use of solvents coupled with the decrease in extraction time and lower power consumption make MAE a technique that meets the principles of green chemistry. MAE operational parameters, extraction time, mass of the sample and extraction temperature, were optimized by RSM （response surface methodology）. Determination of analytes was completed using gas chromatograph coupled to mass spectrometry detection. The selected triazines could be efficiently extracted by the solvent at 80 ℃ for 10 min, with 80% output of maximum power. When the optimized method was applied to analysis samples, the recoveries of analytes ranged from 81.8 to 106.0% and relative standard deviations were lower than 8.41%. The method is stable and reasonable, which can be used for the determination of ninetriazine herbicides residues in soil.

Economic and Qualitative Traits of Italian Alps Saffron

Saffron, obtained from the flower stigmas of Crocus sativus L., is one of the most expensive food spices. The introduction of saffron in alpine areas could help to broaden and diversify the activities of mountain multifunctional farms, with a positive impact on economy and land management. According to ISO 3632(2010/2011), saffron can be classified into three categories of quality(I, II, III) depending on the concentration of the three main metabolites responsible for its characteristic colour, flavor and aroma: Crocin, Picrocrocin and Safranal. This study represents the first investigation of the quality of saffron produced in the Italian Alps evaluated with spectrophotometry, HPLC, solid-phase microextraction(SPME), and gas chromatographic analysis combined with mass spectrometry(GC/MS). The experiments used Crocus sativus stigmas produced in 2012-2013 in different areas of the Central Italian Alps were located at an altitude between 720 and 1200 m a.s.l.. Results obtained were compared to commercial saffron. The analyses confirmed that all samples can be classified in the first quality category according to the ISO classification. This high quality is also confirmed by HPLC analysis. Moreover, the SPME-GC/MS analysis identified some differences in the aromatic profile of saffron samples, in particular regarding safranal concentration. A preliminary assessment of the economic viability of high quality saffron production for local markets was also performed. Our study provides valid information regarding the quality and economic sustainability of saffron production in the alpine area confirming this crop as a good candidate for a new source of income for multifunctional farms in mountain areas.

Enthalpy of phase transition of isonicotinic acid

In this work, the group contribution method of Chickos et al. was applied to estimate the fusion enthalpy of isonicotinic acid, and the obtained result(29.2 k J·mol^(-1)) showed a large difference with the value(135 k J·mol^(-1)) as reported from literatures and as determined by differential scanning calorimetry(DSC). The results of DSC/TG measurement showed that the phase transition of isonicotinic acid from 187.27 °C to277.47 °C underwent a sublimation process, with a sublimation enthalpy of 128.03 k J·mol^(-1). An efficient analytical technique combining pyrolysis and gas chromatography/mass spectrometry(Py-GC/MS) was used to prove this conclusion.

Pyrolysis of Agroindustrial Residues of Coffee, Sugarcane Straw and Coconut-Fibers in a Semi-pilot Plant for Production of Bio-oils： Gas Chromatographic Characterization

Microbial, vegetal or animal organic matter, which has potential to be transformed into energy, is considered biomass. Among the various alternative energy sources, biomass is the only one with the possibility of generating a class of substances of interest for fine chemistry （ketones, aldehydes, alcohols, phenols, etc.）. From biomass, it is possible to produce bio-oil using pyrolysis, a thermodegradation process. The quality of the bio-oil depends on the process conditions （pyrolysis temperature, heating temperature, etc.） and biomass used. In this paper, the pyrolysis （using a fixed bed reactor） of three biomasses （coconut fiber, coffee grounds and sugar cane straw） is studied. The results indicated that the bio-oil yields for all biomass were similar, approximately 37%. The chemical profile obtained by gas chromatography coupled with mass spectrometry （GC/qMS） showed high amounts of fatty acids in the coffee grounds bio-oil and aliphatic and aromatic hydrocarbons in coconut fiber bio-oil, whereas guaiacols were the predominant components of the sugar cane straw bio-oil.

Respiratory Risk Associated with Indoor Air Pollutants in the Form of Settled House Dust

Asthma and allergies are considered by many physicians as being triggered by different substances in the air that people breathe. The lung is the most common site of injury by airborne pollutants. Acute effects, however, may also include non-respiratory signs and symptoms, which may depend upon toxicological characteristics of the substances and host-related factors. The studying of indoor air quality can provide a method for appropriate remedial action. Research suggests that SHD （Settled House Dust） may be a significant source for indoor exposure to different substances. This research study consisted of sampling dust from homes in different area codes. The dust samples were collected from August 2006 thru March 2007 and analyzed using GC/MS （Gas Chromatography/Mass Spectrometry）. The purpose of this research study will display how sampling household dust is a powerful tool for identifying chemicals that contribute to poor indoor air quality.