Papers by Keyword: Gas Chromatography-Mass Spectrometry (GC-MS)

Abstract: Aquilaria species from the family of Thymelaeceae are the main source of gaharu, which has been classified as one of the most highly valuable, non-timber products in the world market. Currently, the method used for extracting gaharu essential oil is by using hydrodistillation. However, this method is inefficient where it produced low yield of oil with long time of extraction and thus increasing the production cost. To overcome this problem, the extraction of gaharu essential oil using Supercritical Fluid Extraction (SFE) with pressure 20MPa, 30MPa and 40MPa at 65 °C for 2 hours was studied. Result obtained after 2 hours of experiment was 0.6% of yield, which was higher compared to 0.2% yield of gaharu essential oil obtained via 3 days of hydrodistillation. After an extraction process, the product will be analyzed by using Gas Chromatography-Mass Spectrometry (GC-MS) to determine the chemical compounds and composition in the Gaharu SFE’s extract. Over eighteen to thirty-one compounds were identified in SFE extract compared with fifty-five identified in the hydrodistillated oil. The mutual occurrence of chemical compounds in all three samples in SFE was dimethyl phthalate, 8-epi-.gama.-eudesmol, diethyl Phthalate and 2-3-Butanediol. In comparison, the major compounds identified in hydrodistillated oil were 4-phenyl-2-butanone, jinkoh-eremol and α-guaiene (Saiful Nizam & Mashitah, 2010). There were certain aromatic sesquiterpenes compounds that were identified in this study, such as Globulol, Alloaromadendrene Naphthalene, 10s, 11s-Himachala-3(12), 4-diene, .delta.-Selinene and (-) - Aristolene.

Abstract: Vinyl acetate, as an important kind of organic chemical raw materials, often adopts the distillation system to separate finished product from raw product. In addition to target products, some residues are produced in the process of distillation, which have a strong damage to the environment, therefore these residues are identified as hazardous wastes to manage and dispose in China. This paper, combined with literature analysis and site investigation, mainly studied production characteristics and particular pollutants of vinyl acetate distillation residue (solid and liquid). To conduct the analysis of the physical and chemical properties of distillation residue, and this paper applied the Gas chromatography-Mass spectrometry (GC-MS) to detemine main particular pollutants, containing Acetic Acid (relative peak area value of 63.47%), 1,1-Ethanediol Diacetate, Crotonic Acid, etc. Meanwhile, this paper can draw another conclusion that treatment and disposal of resource utilization distillation can make more significantly and efficiently use of vinyl acetate distillation residues through the technological contrast of GC-MS.

Abstract: At low temperatures, the copper sulfide ore collectors ester-105 will be solidified and influence the flotation indexes. To this problem, this experiments chemically modify the ester-105, and monitor the synthesis of the modified ester-105 with the use of chromatography-mass spectrometry which is widely applied in chemistry. Thereby, a specific understanding of the modified ester-105 ingredients is gained. Through a copper flotation test with modified ester-105 as collector, it is found that the modified ester-105 can solve the problem that ester can not well sort copper sulfide at low temperatures. This finding is conducive to promote the use of modified ester-105.

Abstract: A novel method has been developed for the determination of bisphenolA in slips of store receipts and ATM machine by head-space liquid-phase micro-extraction (HS-LPME) coupled with gas chromatography-mass spectrometry (GC-MS). The variable experimental conditions for the HS-LPME extraction process were optimized. The optimal conditions were using 2ul of toluene as organic solvent drop, 0.5g of the amount of sample and 1.0cm of the depth of micro-drop from the surface of the sample. After extracting for 10 min and detection limit of 1-100mg·L^-1. Detection limit (3 S/N) of the method was found to be 0.3mg·L^-1, precision and recovery of these methods were tested giving values of RSDs (n=6) less than 4.49%; and of recovery in th range of 98.80%-99.47%. The method shows advantages of simplicity, high sensitivity and high performance extraction to be in line with the analytical standard of the international organic pollutant.

Abstract: This thesis analyzed pit mud lixivium of 20 years, 100 years, 200 years, and 300 years pit age by gas chromatography-mass spectrometry technology. Through analyzing experimental results, 20 kinds of substances were obtained, and 10 kinds of substances were mutual in all pit mud samples. After carefully analyzing many substances in every pit age, the conclusion was obtained that the longer the pit mud had been stored, the more substances it had, the more complicated components were in pit mud, the higher metabolize diversity microorganism had, and the better quality the liquor had.

Abstract: Several Eucalyptus cultivars has been introduced and cultivated for millions of hectares afforestation in subtropical China, whose woods were mainly used in papermaking industry and whose water essential oils were used mainly in aroma and medical industry. However, the potential biomedical components of organic essential oils were still uncovered. In order to reveal constituent characteristic and biomedical potentials of organic essential oils from leaves of four Eucalyptus cultivars (E. camaldulensis, E. tereticornis, E. citriodora and E. dunnii) in China, their components were efficiently extracted by improved solvents extracting condition, which were identified by optimal gas chromatography / mass spectrometry (GC/MS). The functional analytical results suggested that these four Eucalyptus cultivars possess large numbers of common components, especially including Eucalyptol, 1-Eicosanol, (+)-Longifolene, (+)-Aromadendrene, Phytol and (-)-Alloaromadendrene, which are good materials for aroma and biomedical industry. The contents of common components of four Eucalyptus cultivars are as high as 68.97%, 81.81%, 60.64% and 64.29%, respectively. Moreover, each Eucalyptus organic essential oil also has specific components with potentials in aroma industry or biomedical industry.

Abstract: The reason for the natural rubber latex giving out stink during long-term storage or transportation was studied. The stinky component in the latex detected by gas chromatography-mass spectrometry was phenol, the generated content of which increases as the storage temperature rising. It is most possible that the phenol was generated from the decomposition of the inwall coating of iron bucket which loading the natural rubber latex in the strong alkaline during the long-term and high-temperature storage.

Abstract: A novel method was developed for the determination of HCH in Panax Notoginseng of Chinese traditional medicine by ultrasonic extraction (UE) coupled with Gel Permeation Chromatography and Gas Chromatography/Mass spectrometry. Some important parameters that influence the extraction and purification efficiency were investigated. The optimum condition Panax Notoginseng of Chinese traditional medicine was extracted with dichloromethane about 20mL, extracting times and extracting time were one and 30min. The extracts were cleaned up by Gel Permeation Chromatography, and determined by Gas Chromatography /Mass spectrometry. Under the optimum condition, the mean recoveries of the method were 83.23%, the relative standard deviations (RSD) were 3.45%, which has been under the demand of the determination of HCH in Panax Notoginseng of Chinese traditional medicine.

Abstract: The chemical composition of palm and rapeseed biodiesel (fatty acid methyl ester, FAME) was analyzed by gas chromatography-mass spectrometry. Combustion characteristics of biodiesel were studied by thermogravimetry-differential scanning calorimetry and collision theory. Combustion characteristic index C was put forward for describing biodiesel combustion characteristic. The reactive atom combustion mechanism was put forward. Biodiesel combustion process comprised three steps, viz., volatilizing, dissociating and combining. First, biodiesel volatilizes, viz., FAME (liquid) volatilize and became FAME (gas). Second, FAME, O₂ and N₂ molecular were dissociated into C^*, H^*, O^* and N^* reactive atoms. Third, C^*, H^* and N^* reacted, respectively, with O^* to CO₂, CO, H₂O and NO_x, and released energy. The study showed that the biodiesel was mainly composed of FAME: C_14:0-C_24:0, C_16:1-C_22:1, C_18:2 and C_18:3. Biodiesel had a good burnability. Combustion characteristic indexes of palm methyl ester (PME) and rapeseed methyl ester (RME) were 4.97E-05 and 3.65E-05, respectively. The combustion characteristic had relation to chemical composition. The combustion characteristic of biodiesel was better with increasing saturated fatty acid methyl esters and length of carbon-chain, and was poorer with increasing unsaturated fatty acid methyl esters and unsaturated degree. The combustion characteristic of PME was better than that of RME.

Abstract: The ethyl acetate extract was made from the leaves of Sindora glabra by solvent extract method and silica column chromatography, and was analyzed by means of gas chromatography-mass spectrometry. The results show that thirty-four peaks were observed, in which twenty-eight compounds were identified accounting for 93.40% of the total volatile substances detected. The major constituents are Hexadecanoic acid, ethyl ester (12.77%); (1.alpha,4a.alpha,8a.alpha) -7-methyl-4-methylene-1-isopropyl -,1,2,3,4,4a,5,6,8a-octahydro naphthalene (11.95%) and 1,2-Benzenedicarboxylic acid, butyl 2-ethylhexyl ester (11.10%). The main types of compounds are fatty acid esters (44.46%) and terpenoids (25.39%). And most of the terpenoids are sesquiterpenoids which accounted for 23.44% of the total composition.