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Summary Combined capillary gas chromatography/mass spectrometry has been used to characterize the basic fraction of Mexican marijuana and standard tobacco smoke condensates. A thermostable Superox-coated glass capillary column permitted elution of relatively large nitrogen-containing compounds. Substantial qualitative and quantitative differences between the two materials were noted.Dedicated to Dr. L. S. Ettre on the occasion of his 60th birthday. 相似文献
63.
This review covers our extensive research activities in the area of fluorine containing phospha- and arsaalkenes as well as selenocarbonyls, which differ considerably in their properties and reactivities from their alkyl and aryl counterparts and thus contribute in a gratifying manner to the still growing field of unsaturated element-carbon compounds of 3rd and 4th row main group elements E. Of particular interest is the influence of the fluorine substituents and other small groups (OR, NR2) with either inductive and/or mesomeric effects on the polarity and reactivity of the EC bond. Addition reactions of proton acidic and hydridic polar HX reactants as well as [2+2], [3+2] and [4+2] cycloadditions have been thoroughly studied. The results obtained allow a classification of the EC systems within five different types, A to E, and prove a change from “normal” to “inverse” heteroalkenes in this sequence. The ligand properties of some derivatives have also been investigated in some detail. 相似文献
64.
H. Saglam T. Gozler B. Kivcak B. Demirci K. H. C. Baser 《Chemistry of Natural Compounds》2001,37(5):439-441
The chemical composition of the essential oil ofHaplophyllum myrtifoliumBoiss., endemic to Turkey, was examined by GC/MS. Ninety-seven compounds were characterized with linalool (12.8%), -caryophyllene (10.3 %), and methyleugenol (5.9 %) as the main constituents. 相似文献
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The root of Carlina acanthifolia All. (Asteraceae) contained 1.0% of essential oil (expressed in g per 100 g of dried plant material). Using GC and GC/MS,
nine components were identified (100% of total oil). The structure of benzyl 2-furylacetylene (carlina oxide), which is the
principal component of the oil (91.5%), was spectrometrically identified.
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Published in Khimiya Prirodnykh Soedinenii, No. 4, pp. 331–332, July–August, 2005. 相似文献
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建立了使用超高效液相色谱-串联质谱(UHPLC-MS/MS)高效、快速直接测定茶叶中游离氨基酸的方法。通过对质谱、色谱条件及氨基酸提取条件的优化,以含0.2%(体积分数)甲酸的5 mmol/L乙酸铵水溶液和甲醇为流动相进行梯度洗脱,在电喷雾离子(ESI)源正离子扫描模式下检测,通过UHPLC-MS/MS测定,共解析了茶叶中的20种氨基酸。结果表明,茶氨酸(Thea)、Arg、Asn和Asp在50~500 μg/L范围内线性关系良好,其他氨基酸在10~250 μg/L范围内线性关系良好,相关系数均大于0.99;加标回收率为92.3%~109.2%,相对标准偏差为2.00%~9.88%,检出限为0.001~0.011 mg/L,定量限为0.010~0.053 mg/L。该方法灵敏、准确,具有良好的重复性和稳定性,可有效检测出茶叶中的20种氨基酸及氨基类成分。 相似文献
69.
Chetiyanukornkul T Toriba A Kizu R Kimura K Hayakawa K 《Biomedical chromatography : BMC》2004,18(9):655-661
A simple liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) method for the determination of nicotine and cotinine in human hair was established. In the procedure, a hair sample (10 mg) was washed with dichloromethane and digested in 2.5 M sodium hydroxide. The digest was extracted with dichloromethane and then 25 mM hydrochloric acid in methanol was added to the extract, to prevent loss of analytes. The solution was evaporated and redissolved in the mobile phase, methanol/10 mM ammonium acetate (30/70, v/v). A 20 microL aliquot of redissolved solution was subjected to analysis. Nicotine and cotinine in human hair were quantified by using deuterated analytes as internal standards. The quantification limits were 8 microg/L for nicotine and 0.9 microg/L for cotinine. The proposed method was applied to measure the concentrations of nicotine and cotinine in hair of smokers and non-smokers to evaluate their self-reported smoking and exposure to environmental tobacco smoke. In both cases, the method provided good selectivity, accuracy and precision. 相似文献
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