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41.
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.
__________
Published in Khimiya Prirodnykh Soedinenii, No. 4, pp. 331–332, July–August, 2005. 相似文献
42.
研究了丙烯腈/苯乙烯(AN/St)悬浮共聚体系中AN在水/油两相间的分配及其对AN/St共聚物组成的影响.结果表明,AN分配于水/油两相间,使油相AN的含量低于相同单体配料比的本体聚合,导致生成的AN/St共聚物组成偏离本体共聚.为了准确预测进而控制AN/St悬浮共聚物的组成,提出了在考虑AN相分配的基础上计算AN/St悬浮共聚物组成的模型.计算结果与实验值一致,计算中用到的油相实际竞聚率与本体聚合相同,但该悬浮聚合的表观竞聚率随水/油比的变化而发生较大改变. 相似文献
43.
A comparative study of the performance of liquid chromatography (LC)-atmospheric pressure chemical ionisation (APCI)-mass spectrometry (MS) and gas chromatography (GC)-mass spectrometry techniques for the determination of resin and fatty acids from paper mill process waters was carried out. These compounds are responsible for the high toxicity of paper mill effluents and little research has been carried out regarding their analysis using mass spectrometric techniques. To prove the usability of GC and LC-MS, 16 treated and untreated water samples of recycle, kraft and pulp paper mills were analysed and good agreement was observed as regards to compounds detected and corresponding concentrations. This paper also reports the limits of detection, recoveries, reproducibility, linearity and precision using the two methods. GC-MS presented better selectivity and lower detection limits (below 0.2 microg/l), but derivatization of the extracts and the short life of derivatives (12-24 h) made the technique tedious and prone to high variations. Although LC-APCI-MS presented coelution of the non-aromatic resin acids, it also showed good sensitivity (limits of detection <3 microg/l) and permitted the detection of resin and fatty acids at microg/l level. In addition, since samples could be directly injected to the chromatographic system, LC-APCI-MS was proven as a powerful technique for quick and unequivocal quality control during papermaking. 相似文献
44.
45.
Hoffman BJ Taylor LT Rumbelow S Goff L Pinkston JD 《Journal of chromatography. A》2004,1043(2):285-290
Supercritical fluid chromatography (SFC) was used for the analysis of ethoxylated and propoxylated surfactants. Samples were derivatized to phenylated silyl ethers with a disilazane-chlorosilane mixture. Addition of a phenyl group to the surfactant allowed UV-absorbance detection of each oligomer. Acetonitrile and methanol were evaluated as mobile phase modifiers. Better peak shape was realized with methanol-modified CO2 on an octadecyl silica bonded phase than with acetonitrile-modified CO2. Peak assignments were made via SFC coupled with electrospray ionization-mass spectrometry (ESI-MS) in the positive ion mode. A sulfonamide-embedded alkyl stationary phase was also evaluated for separation of the derivatized samples. SFC-UV and SFC-ESI-MS data were jointly used for calculation of average molar oligomer values which were then compared to values calculated from 1H NMR data of non-derivatized samples. The derivatization or separation method using the sulfonamide embedded phase required no preliminary cleanup and yielded reproducible oligomer values that were consistent with those of the manufacturer's nominal values. 相似文献
46.
Verardo G Pagani E Geatti P Martinuzzi P 《Analytical and bioanalytical chemistry》2003,376(5):659-667
The composition of the surface waxes of three apple ( Malus domestica L.) cultivars ("Florina", "Golden B" and "Ozark Gold") has been studied by means of spectroscopic and GC–MS analysis of the class-fractionated mixture of components. Odd n -alkanes, mainly C27 and C29 molecules, are prevalent in the saturated fraction. Small concentrations of alkenes were also found; the C28:1 component is strongly (72%) in excess over the other 1-alkenes. Straight-chain esters (mainly of palmitic acid) of saturated primary alcohols (C18–C30) were also detected; whereas the acyl moiety is made up essentially of an even number of carbons, the alcohol counterpart does not exhibit this characteristic. Aldehydes are present (C20–C30) with the homologue patterns C26–C30 most strongly represented. Straight-chain free secondary alcohols characterize the waxes of "Florina" and "Ozark Gold"; the hydroxy function is located far from the extremity of the carbon framework. Outstanding is the presence of three alcohols with 29 carbon centres. These alcohols are accompanied by free straight-chain primary alcohols, mainly with even-numbered carbon chains in the range C26–C30. Free fatty acids are present; all of have a framework of even-numbered carbon chains mainly in the range C16–C20. C18:1 (oleic acid) is well represented. 相似文献
47.
Summary Ten pesticides have been completely separated by two-dimensional (2D) development on TLC plates coated with coupled layers
of octadecyl silica (reversed-phase, RP) and plain silica (normal-phase, NP). The binary mobile phases, aqueous-organic for
RP chromatography and nonaqueous for NP chromatography, were chosen from plots ofR
F against mobile-phase composition and graphicalR
F(RP)-R
F(NP) correlations. The different selectivity of the RP and NP systems enabled dispersion of spots over the plate area and good
separation. 相似文献
48.
Summary A theoretical treatment is presented which considers differences between the composition of the mobile phase and solvents
that are incorporated into the bonded phase via preferential sorption. Equations are derived and used to analyze retention
data for various homologs chromatographed under reversed-phase conditions using alkyl bonded phases and combinations of water-methanol,
water-acetonitrile and watertetrahydrofuran as mobile phases. In the case of water-methanol the surface phase and bulk mobile
phase compositions are similar. However, significant differences in composition between the two phases are observed when binary
combinations of water-acetonitrile and water-tetrahydrofuran are used as the cluents. 相似文献
49.
50.