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排序方式: 共有721条查询结果,搜索用时 31 毫秒
571.
Duhamel Lauren Gu Yan Barnett Gregory Tao Yuanqi Voronov Sergey Ding Julia Mussa Nesredin Li Zheng Jian 《Analytical and bioanalytical chemistry》2019,411(21):5617-5629
Analytical and Bioanalytical Chemistry - Positive identification of capillary electrophoresis-sodium dodecyl sulfate (CE-SDS) electropherogram peaks provides information to understand protein... 相似文献
572.
David A. Barnett Barbara Ells Roger Guevremont Randy W. Purves 《Journal of the American Society for Mass Spectrometry》1999,10(12):173-1284
An electrospray ionization (ESI) source was used to generate gas-phase molecular anions of the amino acids leucine and isoleucine ((M–H)−; m/z −130), which were separated by high- field asymmetric waveform ion mobility spectrometry (FAIMS) and detected by quadrupole mass spectrometry (MS). This combination of ESI-FAIMS-MS enabled selective determination of either amino acid in mixtures that contained at least a 625-fold excess of the other. Comparisons with conventional ESI-MS showed a 50-fold improvement in the signal to background ratio for a 1 μM solution of leucine. 相似文献
573.
574.
F. M. Miatto D. Giovannini J. Romero S. Franke-Arnold S. M. Barnett M. J. Padgett 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2012,66(7):1-6
We propose a scheme to evidence the Einstein-Podolsky-Rosen (EPR) paradox for photons produced by spontaneous down conversion, from measurement of purely spatial correlations of photon positions both in the near- and in the far-field. Experimentally, quantum correlations have been measured in the far-field of parametric fluorescence created in a type II BBO crystal. Imaging is performed in the photon counting regime with an electron-multiplying CCD (EMCCD) camera. 相似文献
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576.
OBJECTIVES: To examine whether being a BRCA1/2 mutation carrier affects a wide array of aspects of life, and if so, how. METHODS: Participants were grouped according to their carrier status (carrier and noncarrier status), health status (affected or unaffected by cancer), and their enrollment at the counseling service (probands and other family members). One hundred and sixty-five women completed a self-administered questionnaire following their genetic consultation session. RESULTS: Probands/nonprobands and carriers/noncarriers did not differ with regard to demographic characteristics, health behaviors including medical checkups, the distress they experience or their resources (sense of coherence, social integration, religiosity). Individuals affected by cancer did differ on some of these aspects from participants without cancer. CONCLUSIONS: From the results of this study, being a carrier could not be considered a psychosocial risk factor, nor does it seem to have an effect on carriers' resources and lifestyle. 相似文献
577.
Investigating retention characteristics of a mixed‐mode stationary phase and the enhancement of monolith selectivity for high‐performance liquid chromatography 下载免费PDF全文
Danielle N. Bassanese Arianne Soliven Paul G. Stevenson Gary R. Dennis Neil W. Barnett Ross A. Shalliker Xavier A. Conlan 《Journal of separation science》2014,37(15):1937-1943
The synthesis and chromatographic behavior of an analytical size mixed‐mode bonded silica monolith was investigated. The monolith was functionalized by an in situ modification process of a bare silica rod with chloro(3‐cyanopropyl)dimethyl silane and chlorodimethyl propyl phenyl silane solutions. These ligands were selected in order to combine both resonance and nonresonance π‐type bonding within a single separation environment. Selectivity studies were undertaken using n‐alkyl benzenes and polycyclic aromatic hydrocarbons in aqueous methanol and acetonitrile mobile phases to assess the methylene and aromatic selectivities of the column. The results fit with the linear solvent strength theory suggesting excellent selectivity of the column was achieved. Comparison studies were performed on monolithic columns that were functionalized separately with cyano and phenyl ligands, suggesting highly conjugated molecules were able to successfully exploit both of the π‐type selectivities afforded by the two different ligands on the mixed‐mode column. 相似文献
578.
Screening of cannabinoids in industrial‐grade hemp using two‐dimensional liquid chromatography coupled with acidic potassium permanganate chemiluminescence detection 下载免费PDF全文
Jessica Pandohee Brendan J. Holland Bingshan Li Takuya Tsuzuki Paul G. Stevenson Neil W. Barnett James R. Pearson Oliver A.H. Jones Xavier A. Conlan 《Journal of separation science》2015,38(12):2024-2032
Widely known for its recreational use, the cannabis plant also has the potential to act as an antibacterial agent in the medicinal field. The analysis of cannabis plants/products in both pharmacological and forensic studies often requires the separation of compounds of interest and/or accurate identification of the whole cannabinoid profile. In order to provide a complete separation and detection of cannabinoids, a new two‐dimensional liquid chromatography method has been developed using acidic potassium permanganate chemiluminescence detection, which has been shown to be selective for cannabinoids. This was carried out using a Luna 100 Å CN column and a Poroshell 120 EC‐C18 column in the first and second dimensions, respectively. The method has utilized a large amount of the available separation space with a spreading angle of 48.4° and a correlation of 0.66 allowing the determination of more than 120 constituents and mass spectral identification of ten cannabinoids in a single analytical run. The method has the potential to improve research involved in the characterization of sensitive, complex matrices. 相似文献
579.
580.
N. W. Barnett Simon W. Lewis Daryl J. Tucker 《Fresenius' Journal of Analytical Chemistry》1996,355(5-6):591-595
A procedure for the determination of morphine in process streams by sequential injection analysis based on the chemiluminescence reaction of morphine with acidic potassium permanganate in the presence of sodium hexametaphosphate is presented. The chemiluminescence emission has been monitored using an in-house detection system which consisted of a fibre optic flowthrough cell and a sensitive, low dark current, photomultiplier tube. The calibration graph (range 2 × 10–8 to 1 × 10–4 mol/l) was not linear over the entire range of concentration, with a polynomial equation of best fit of y = 1.0 × 1015 x3 – 2.2 × 1011 x2 + 1.3 × 107 x – 8.3. The calibration function approximates linearity over the concentration range 2.5 × 10–6 to 3.0 × 10–5 mol/l where the slope of the log-log plot is 1.09 ± 0.16. The detection limit was estimated at about 10–8 mol/l from the response of the lowest calibration standard (2.5 × 10–8 mol/l) which gave a signal to noise ratio of 3 : 1. Although the structurally related codeine did not interfere significantly the results suggest that this method may be susceptible to matrix effects, dependent on the location of sampling from the process stream. 相似文献