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1.
2.
Investigation of Tomato Plant Defence Response to Tobacco Mosaic Virus by Determination of Methyl Salicylate with SPME-Capillary GC-MS 总被引:2,自引:0,他引:2
Headspace SPME was applied to investigation of tomato plant defence response to tobacco mosaic virus (TMV) by determination of compounds emitted from tomato plants at the extraction conditions of 25 °C and 15 min. It was found that TMV-inoculated tomato plant released large amount of methyl salicylate (MeSA) as response to TMV and MeSA concentration changed dramatically with time after inoculation. Gaseous MeSA as a signaling compound could induce in surrounding tomato plants to produce salicylic acid (SA) and synthesize and release MeSA. These results show that MeSA might be an airborne plant-signalling molecule in tomato plant response to TMV. The present method provided low detection limit of 2.0 ng L–1 and needed little sample preparation time (15 min), so the method makes it easy to find the critical times of tomato plant response to TMV by fast determination of MeSA released from tomato plant. 相似文献
3.
Xiaofang Wan Youming Li Xiaojun Wang Sili Chen Xiaoyang Gu 《European Polymer Journal》2007,43(8):3655-3661
Acrylamide grafted cationic guar gum (CGG-g-PAM), induced by ceric ammonium sulfate, was synthesized using aqueous polymerization technique at 10 °C and the flocculation property was studied with high-turbidity tobacco wastewater (NTU > 4500). Thus five grades of graft copolymers were obtained through alteration of initiator and monomer concentrations in order to understand the effect of molecular weight on flocculation. The grafted copolymer was characterized by FTIR and SEM. Study of DTG demonstrated that CGG-g-PAM had better heat-resistant performance than guar gum, cationic guar gum (CGG) and polyacrylamide. The dosage of polyaluminium chloride (PAC) and CGG-g-PAM, pH value and molecular weight were considered to be the factors that can influence flocculation efficiency. The result showed best flocculation efficiency occurs at pH 5 when the dosage of CGG-g-PAM and PAC are 3.6 ppm and 120 ppm, respectively. The percentage of turbidity and COD removal are 98% and 24% correspondingly, and its flocculating efficiency prevails over that of CGG and cationic polyacrylamide (CPAM). 相似文献
4.
Summary The aim of this investigation was to obtain qualitative and quantitative profiles of the flavonoid and biflavonoid composition
of six cypress species—Cupressus funebris L.,Cupressus sempervirens L.,Cupressus glabra L.,Cupressus arizonica L.,Cupressus goveniana L., andCupressus lusitanica L. HPLC-diode-array detection (DAD), HPLC-MS, and HPTLC were used to identify the individual compounds. A chromatographic
method was optimized for identification and quantification of the main flavonoid glycosides and biflavonoids. The flavonoids
identified and calibrated were: rutin, quercetin glucoside, quercetin rhamnoside, and kaempferol 3-O-rhamnoside. The biflavonoids identified and calibrated were: cupressuflavone, amentoflavone, robustaflavone, hinokiflavone,
methylrobustaflavone, methylamentoflavone, and dimethylcupressuflavone. 相似文献
5.
Supercritical fluid extraction of flumetralin in tobacco 总被引:2,自引:0,他引:2
Summary This work evaluates the level of Flumetralin residues in real tobacco samples. Conventional extraction methods were compared with SFE methods in both static and dynamic modes using CO2 and CO2 with modifier. Additionally, in the dynamic SFE mode, different collection approaches, such as collection at room temperature without solvent, collection at room temperature in the presence of solvent (hexane) and collection in an ice bath, without solvent, were studied. SFE showed itself to be a promising extraction technique for pesticide residues in tobacco samples. 相似文献
6.
7.
S. S. Yang 《Chromatographia》1992,33(7-8):309-312
Summary A rapid sample preparation procedure combined with a short reversed-phase HPLC separation for the quantitation of methoprene residue in tobacco samples is described. A ground tobacco sample of 0.5 g is mixed with 3 mL of 2-propanol. The mixture is extracted for twelve minutes with the aid of sonication at an elevated temperature (45–55°C) and then filtered through a 0.45 m disposable filter prior to injection on HPLC. No sample cleanup or solvent evaporation step is required. Chromatographic analysis is performed on a C-18 column and the analysis time is 12.5 minutes. The detection limit for methoprene in tobacco samples is one part per million (g/g). 相似文献
8.
Summary The essential oils have been isolated from tobacco leaves using a simple gas co-distillation apparatus. The method involves co-distillation with water under the continuous stream of an inert gas with subsequent single solvent extraction of the distillate. The extract is analysed on GC and GC/MS in splitless injection mode without further concentration. The method was evaluated for reproducibility using n-octadecane as an internal standard. The distillation-extraction procedure was reporducible with an average deviation of ±3% for the major constituents. The present method was applied to the analyses of the essential oils of other agricultural products.Dedicated to Dr. L. S. Ettre on the occasion of his 60th birthday. 相似文献
9.
A novel extraction method, namely dynamic ultrasound-assisted extraction, is investigated. This technique is efficient with respect to both time and solvent consumption because it utilizes ultrasonic energy in dynamic mode during extraction. Polyphenols (chlorogenic acid, esculetin, rutin, scopoletin, and quercitrin) are extracted from a tobacco (Nicotina tobaccum L.) sample for 10 min with 6 mL of solvent. Fresh solvent is continuously pumped through the sample, with which the analytes can be rapidly extracted, and the possibility of degradation efficiently avoided. Methanol involving 0.5% w/v ascorbic acid was used as extraction solvent; optimal flow rate and extraction time were investigated. The extract was cleaned up by C18 disposable cartridge. The spiked and nonspiked tobacco samples were used for the evaluation of the proposed method. Recoveries obtained were varied from 96 to 108% and RSDs from 2.0 to 4.6%. This extraction technique was revealed to recover larger amounts of polyphenols from tobacco, compared to the static ultrasound-assisted extraction method. 相似文献
10.
A new extraction method for ginsenosides from ginseng roots, ginseng leaves and ginseng drug preparations by Sep-Pak C18 cartridges has been studied. Ginsenoside extraction by Sep-Pak cartridges is a rapid, efficient, reproducible method. In addition, the extracts were analyzed by high performance thin layer chromatography (HPTLC) and reverse phase high performance liquid chromatography (HPLC). The major components of ginseng saponins were effectively separated using an ODS-120T column. 相似文献