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1.
Paula M. Knight Michael W. Scherz C. A. Cruze Kenneth R. Wehmeyer 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1997,700(1-2):111-118
A sensitive and selective GC-MS method was developed for the determination of low levels of a novel antiinflammatory agent, 1-(7-tert.-butyl-2,3-dihydro-3,3-dimethylbenzo[b]furan-5-yl)-4-cyclopropylbutan-1-one (I), in small volumes of animal plasma. The method involved the addition of 13C6-labeled-I to plasma samples, followed by a simple liquid-liquid extraction with hexane to isolate the analytes from matrix components. The levels of I in the sample extracts were determined by isotope-dilution GC-MS analysis using selected-ion monitoring. The method was linear over three orders of magnitude, with a limit of quantitation of 1.8 ng/ml I, using plasma sample volumes of 0.1 ml. The method was utilized to determine the pharmacokinetic parameters of I in rats and dogs, following intravenous administration. 相似文献
2.
Partial site-specific assignments are reported for the solid state NMR spectra of light-harvesting complex 1, a 160 kDa integral membrane protein. The assignments were derived from 600 MHz 15N-13CO-13Cα and 15N-13Cα-13CX correlation spectra, using uniformly 13C, 15N enriched hydrated material, in an intact and precipitated form. Sequential assignments were verified using characteristic 15N-13Cα-13Cβ side chain chemical shifts observed in 3D experiments. Tertiary contacts found in 2D DARR spectra of the selectively 13C enriched sample provided further confirmatory evidence for the assignments. The assignments include the region of the Histidine ligands binding the Bacteriochlorophyll chromophore. The chemical shifts of Cα and Cβ resonances indicated the presence of typical α-helical secondary structure, consistent with previous studies. 相似文献