用气质联谱测定褐飞虱体内的保幼激素

用气质联谱法检测了稻褐飞虱 1～ 5龄若虫及羽化后 1d的成虫的保幼激素滴度 ,结果表明在各龄若虫及成虫的各种翅型下都能检测到 JH1 和 JH3。以 JH3滴度计算 ,就 1龄、2龄、3龄、4龄、5龄以及成虫而言 ,其检测下限分别为 2 5、15、15、10、1、1头。此方法测定的全过程回收率 JH1 和 JH3分别为 91.3%和 95 .7%。

应用同时蒸馏萃取与气质联谱法测定天麻低极性组分

研究利用同时蒸馏萃取装置,以CH2Cl2为溶剂,提取鲜、干天麻样品中的低极性组分,通过GC-MS测定,用峰面积归一化法确定相对百分含量。结果表明:鲜干天麻中低极性组分及其含量的差异均较明显,但也有共同的成分。鲜天麻中的低极性组分和含量均高于干天麻样品中的低极性组分,鲜天麻中有较高含量的酯类。

用气质联谱法测定中华蜜蜂体内保幼激素

保幼激素是由蜜蜂咽侧体分泌出的一类高萜类化合物,在蜜蜂生长发育、变态以及生殖发育过程中扮演着重要的角色。本实验用气质联谱法检测了中华蜜蜂1,3,5日龄幼蜂的保幼激素含量。结果表明:在各龄中华蜜蜂体内都能检测到JH3,且蜜蜂随日龄增长,体内保幼激素含量增加。

木棉花CO_2超临界萃取物的GC-MS分析

对木棉花超临界CO2 萃取物进行了GC MS分析 ,分得 88个峰 ,鉴定了其中 64种成分 。

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.

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.

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.

Determination of 10 Pyrethroids Pesticide Residues in Rice by GC-MS-MS

[Objective] A method was developed for the determination of 10 pyrethroids pesticide residues in rice by GC-MS-MS. [Method] Pyrethroids were extracted with acetonitrile, followed by a salting-out step with anhydrous magnesium sulfate and sodium chloride, cleaned up by florisil solid phase extraction （SPE） cartridge, and determined by multiple reaction monitoring mode. [Result] The method showed good linearity over the range of 0.010-0.500 mg/L for 10 pyrethroid pesticide with correlation coefficients over 0.99. The detection limits were 0.005 -0.010 mg/kg. The method was validated by analyzing samples spiked with 0.05, 0.10, 0.20 mg/kg of 10 pyrethroid pesticides, respectively. The average recoveries in rice ranged from 75.0-115.5%, and the relative standard deviations （RSD） were between 3.9%-6.9%. [Conclusion] The method is easy, accurate and reliable, which can meet the requirement for the simultaneous determination and confirmation of pyrethroid pesticide residues in rice.

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.

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.

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.

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.

Chemical composition of the essential oil from Rabdosia lophanthoides

Gas chromatography/mass spectrometry (GC MS) of the essential oil from the aerial parts of Rabdosia lophanthoides resulted in the identification of 108 compounds representing 78.120% of the oil. Hydro distillation of Rabdosia lophanthoides yielded a pale yellow oil. The compounds identified and their relative proportions are listed in Table 1 according to their order of elution on an HP 5MS capillary column. .

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.

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.

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.

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.