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At least 1,747 records · Page 97Linked to original sources
PubMed2003

[The emission flux of volatile organic compounds in the Inner Mongolia Grassland].

During the summer season of 2002, emissions of volatile organic compounds were firstly measured by a static enclosure technique at a grassland site in the Inner Mongolia grassland. The parameters including solar radiation, air temperature and relative humidity were also measured in the same time period. The results showed that isoprene was the main component of volatile organic compounds emitted from the grassland. Isoprene exhibited an evident diurnal, daily and seasonal variation. Solar visible radiation, air temperature and water vapor content were the main factors to affect isoprene emission, and solar visible radiation was the most important factor to control the isoprene emission. Base on the correlation analysis, when considering the affecting factors of isoprene emission, it is not only to consider solar visible radiation, temperature, but also the water vapor. It is impossible to avoid the changes of solar radiation, temperature and humidity between inside and outside the chamber by using the enclosure technique. So, it is necessary to take these effects into the considerations and modify isoprene emission. In summer 2002, the maximum emission flux (C) of isoprene was 1649.3 micrograms/(m2.h), and monthly averaged emission flux (C) in June, August and September were 886.6, 707.0 and 427.2 micrograms/(m2.h), respectively.

Air↗
PubMed2003

[Ammonia volatilization loss of nitrogen fertilizer from rice field and wet deposition of atmospheric nitrogen in rice growing season].

Plot and field experiments showed that the NH3 volatilization loss from rice field reached its maximum in 1-3 days after N-fertilization, which was affected by the local climate conditions (e.g., sun illumination, temperature, humidity, wind speed, and rainfall), fertilization time, and ammonium concentration in surface water of the rice field. The wet deposition of atmospheric nitrogen was correlated with the application rate of N fertilizer and the rainfall. The amount of nitrogen brought into soil or surface water by the wet deposition in rice growing season reached 7.5 kg.hm-2. The percent of NH4(+)-N in the wet deposition was about 39.8%-73.2%, with an average of 55.5%. There was a significant correlation of total ammonia volatilization loss with the average concentration of NH4(+)-N in wet deposition and total amount of wet deposition in rice growing season.

Ammonia↗
PubMed2003

[Study on the constituents of volatile oil from Ocimum basilicum].

OBJECTIVE: To study the constituents of volatile oil from Ocimum basilicum. METHOD: GC-MS technique was used. RESULT: Forty-five compounds was elucidated through consulting literature and searching database by computer. CONCLUSION: The main constituent in volatile oil from O. basilicum are 1, 7-dimethyl-1, 6-octadien-3-ol, which accounts for 29.87%.

Gas Chromatography-Mass Spectrometry↗
PubMedDate not supplied

[Influence of volatile metabolites of saprophytic soil microflora on the propagation of pathogenic bacteria].

The influence of volatile metabolites of saprophytic soil microflora on the propagation of Listeria monocytogenes and Yersinia pseudotuberculosis is shown. Different character of interspecific relationships between bacteria, influencing their propagation, can be observed on the metabolic level. Volatile compounds produced by microorganisms are capable to act as both intra- and interspecific regulators of microbial communities. In this connection the propagation of pathogenic bacteria inhabiting soil may be stimulated or inhibited by the metabolic products of soil microorganisms. Methanol released by saprophytic bacteria into the environment play an important role in this process.

Bacteria↗
PubMed2004

[Assessment of the emission of volatile organic compounds from polyurethane foams].

The emission of 2,4- and 2,6-diaminotoluene, triethylenediamine, diethanolamine and other volatile organic compounds from polyurethane foams was examined in environmental chamber. Tested materials did not release of amines. The emission of total volatile organic compounds showed differences for polyurethane samples but did not exceed ecological standards.

Air Pollutants↗
PubMed2004

[Study on GC-MS fingerprint analysis in rhizome of volatile oil of Acorus tatarinowii].

OBJECTIVE: To establish the method of fingerprint analysis on volatile oil in rhizome of Acorus tatarinowii by GC-MS, and to study the main characteristic components. METHOD: The main components of 10 samples were determined by GC-MS. RESULT: The injector temperature was 250 degrees C. The interface temperature was 230 degrees C. The column flow was 1.3 mL x min(-1). The column pressure was 80 kPa. The detector volt was 1.4 kV. The temperature rate was 3 degrees C x min(-1). And the main characteristic components were composed of the methyleugenol (2.13%), cis-methylisoeugenol (4.48%), trans-methylisoeugenol (0.82%), gamma-asarone (4.51%), beta-asarone (66.15%), alpha-asarone (6.35%). And the RSD of precision and reproducibility and stability was almost in the range of 5%. CONCLUSION: The method is reliable, accurate and can be used for fingerprint analysis of volatile oil of Acorus tatarinowii.

Acorus↗
PubMed2004

[Study on liposome preparation technique of Bupleurum chinense volatile oil for injection].

OBJECTIVE: To study the preparation technique of the liposome of Bupleurum chinense volatile oil. METHOD: The composition, entrapment ratio of volatile oil, availability of freeze-drying and the changes of finger prints were studied. RESULT: Entrapment ratio reached 81.9%. After freeze-dried, the remaining ratio of the oil entrapped in the liposome reached 88.6%. CONCLUSION: It is practicable to make B. chinense injection into freeze-dried liposome powder.

Bupleurum↗
PubMed1997

[Characterization of volatile organic compounds from indoor materials].

Volatile organic compounds emitted from eight indoor materials including paint, wallpaper glue, maticolor coat, floorwax floor covering and air freshener and were analyzed by headspace GC-FID and GC-MS. About 3-30 organic compounds were detected from each material. It was shown that the emitted compounds and emission rate from different materials were different. The emitted compounds included paraffin, olefine, alcohol, aldehyde, ether, ester and aromatic compounds. The results of dynamic experiments in test chamber showed that the chamber concentration of volatile organic compounds from paint vs. time data follows a double exponent equation.

Air Pollutants↗
PubMed2004

[Re-study on characteristic fingerprint of volatile oil from Herba Pogostemonis by GC].

OBJECTIVE: To establish the characteristic fingerprint and parameter of volatile oil from Herba Pogostemonis. METHODS: The dffferent collecting time and county samples of Herba Pogostemonis were determined by GC. RESULTS: Accuracy, stability and repeatability of the method were good. The same region samples had good stability and main constituents were same in different collection time, but content were different. The samples collected from different region were more different in constituents and content. CONCLUSION: The 11 components in common buildup the characterisitic fingerprint of volatile oil from Herba Pogostemonis. The ratiio of pogostone to patchoulic alcohol were used index parameter for quality evaluation and characteristics of producing region.

China↗
PubMed2004

[Study on extraction process of the volatile oil for biyuan dropping pills].

OBJECTIVE: To determine the optimal extracting process of the volatile oil for Biyuan Dropping Pills. METHODS: Conditions for the extraction were studied by orthogonal design guided by the increasement of the volatile oil. RESULTS: The distilling time is the main factor,and the fineness of the herbal material is the second. The optimal process is as follows: crush the herbal material into coarse powder, macerate 1 hour with 9 times water and distill 4 hours. CONCLUSION: The optimized process is feasible and stable.

Analysis of Variance↗
PubMedDate not supplied

Comparison of solid-phase microextraction, supercritical fluid extraction, steam distillation, and solvent extraction techniques for analysis of volatile consituents in Fructus Amomi.

Four sampling techniques, solid-phase microextraction (SPME), supercritical fluid extraction (SFE), steam distillation (SD), and solvent extraction (SE), were compared for the analysis of volatile constituents from a traditional Chinese medicine (TCM) of the dried ripe fruit of Fructus Amomi (Sha Ren). A total of 38 compounds were identified by gas chromatography/mass spectrometry. Different SFE and SPME parameters (modifier content, extraction pressure, and temperature for SFE and fibers, extraction temperature, and time for SPME) were studied. The results by SFE and SPME were compared with those obtained by conventional SD and SE methods. The results showed that SFE and SPME are better sample preparation techniques than SD and SE. Due to SFE's requirement for expensive specialized instrumentation, the simplicity, low cost, and speed of SPME make it a more appropriate technique for extraction of volatile constituents in TCMs.

Amomum↗
PubMed2002

[Analysis of volatile constituents of root and rhizome of Asarum heterotropoides Fr. var. mandshuricum (Maxim.) Kitag. by gas chromatography-mass spectrometry].

The volatiles of root and rhizome of Asarum heterotropoides Fr. var. mandshuricum (Maxzim. ) Kitag. were extracted with n-hexane and analyzed by capillary gas chromatography-flame ionization detection and gas chromatography-mass spectrometry (GC-MS) with the same column HP-5 (30 m x 0.25 mm i.d.). Initial oven temperature was kept at 40 degrees C for 2 min, then raised to 160 degrees C at 3 degrees C /min, immediately raised to 250 degrees C at 6 degrees C /min, and kept 250 degrees C for 23 min. According to GC-MS analysis, 36 compounds were identified. The main components are safrole, methyleugenol, 3,5-dimethoxytoluene, pentadecane, N-isobutyldodecatetraenamide. Furthermore, the analysis results of root and rhizome were compared. The results indicate that the fundamental constituents are nearly the same, but the quantities of volatiles in root are richer than those in rhizome. In addition, 8 compounds are selected as the criteria of quality control, including 3-carene, 1,8-cineole, eucarvone, methyleugenol, safrole, myristicin, pentadecane and N-isobutyldodecatetraenamide.

Asarum↗
PubMed1991

Epstein-Barr virus activators, mutagens and volatile nitrosamines in preserved food samples from high-risk areas for nasopharyngeal carcinoma.

Representative samples of preserved foods collected from high-risk areas for nasopharyngeal carcinoma were assayed for capacity to induce Epstein-Barr virus (EBV) by measuring induction of the DR promoter gene or of genes for early antigens in Raji cells. The two assays gave concordant results, but the DR induction assay detected EBV-inducing substances at lower concentrations and more reproducibly. Three of 17 preserved food items were active in both assays; they were also weakly mutagenic in the SOS chromotest and contained low or moderate levels of volatile N-nitrosamines. After in-vitro nitrosation, the levels of mutagens and nitrosamines increased, whereas EBV-inducing activity was unchanged or decreased. Thus, EBV inducers appear to be a different class of substances from mutagens and volatile N-nitrosamines but could act with them in the etiology of nasopharyngeal carcinoma.

Food Analysis↗
PubMed2006

[Evaluation of cyclodextrin inclusion of the volatile components in compound traditional Chinese medicine].

OBJECTIVE: To study the factors affecting cyclodextrin (CD) inclusion of the volatile components in compound traditional Chinese medicines and evaluate the stability of the inclusion compound. METHODS: This study took Gengnian compound as an example to examine the factors affecting the inclusion process according to the inclusion compound utilization ratio. Orthogonal design method was employed optimize the parameters in the inclusion process. The moisture absorption rate of the beta-CD inclusion compound was determined in different humidity and Q10 was used to predict its. RESULTS: The inclusion method, inclusion compound dosage, temperature, inclusion time, and the drying method could all obviously influence the inclusion process. The results of orthogonal design study showed that the optimal beta-CD inclusion of Gengnian compound volatile components could be achieved by adding 8-fold volume of beta-CD and stirring for 3 h at room temperature. Stability experiment showed that the humility did not significantly influence the inclusion compound, which can be stable for 1.26 years. CONCLUSION: This study comprehensively examines the factors affecting the inclusion process and the stability of the inclusion compound, and provides experimental basis for application and study of the inclusion technology.

Drug Combinations↗
PubMed2006

[Effects of nitrogen application level on soil nitrate accumulation and ammonia volatilization in high-yielding wheat field].

The study showed that during the period from sowing to pre-wintering, the soil nitrate in high-yielding wheat field moved down to deeper layers, and accumulated in the layers below 140 cm. An application rate of 96-168 kg N x hm(-2) increased the nitrate content in 0-60 cm soil layer and the wheat grain yield and its protein content, and decreased the proportion of apparent N loss to applied N and the ammonia volatilization loss from basal nitrogen. Applying 240 kg N x hm(-2) promoted the downward movement of soil nitrate and its accumulation in deeper layers, increased the proportion of apparent N loss to applied N and the ammonia volatilization loss from basal nitrogen, had no significant effect on the protein content of wheat grain, but decreased the grain yield. The appropriate application rate of nitrogen on high-yielding wheat field was 132-204 kg N x hm(-2).

Ammonia↗
PubMed2006

[Analysis on the volatile oil in Origanum vulgare].

OBJECTIVE: To analysis compositions of the volatile oil in Origanum vulgare. METHODS: GC-MS condition: using programmed temperature gas chromatography cinitial temperature was 60 degrees C, and then raising the temperature (5 degrees C/min) to 240 degrees C, mass-to-electric charge ratio was 10 to 425. RESULTS: GC-MS identified 29 kinds of contents. CONCLUSION: Thymol and carvacrol are main compositions of the volatile oil in Origanum vulgare.

Cymenes↗
PubMed1990

[Stability examination of the inclusion compounds of 8 Chinese medicinal volatile oils with beta-cyclodextrin].

The content, hence the stability of volatile oils and their main components in the inclusion compounds of 8 Chinese medicinal volatile oils with beta-cyclodextrin have been examined with different storage times. The 8 Chinese medicines are Vitex negundo var. heterophylla, Notopterygium incisum, Alpinia officinarum, Atractylodes lancea, Pogostenon cablin, Asarum heterotropoides var. mandshuricum, Schizonepeta tenuifolia and Amomum villosum.

Cyclodextrins↗