排序方式: 共有24条查询结果,搜索用时 93 毫秒
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采用超高效液相色谱-四极杆飞行时间质谱(UPLC-Q-TOF MS/MS)技术,建立了睫毛用化妆品中9种前列腺素F2α类化合物(比马前列素、曲伏前列素、他氟前列素、他氟乙酰胺、拉坦前列素、比马前列素酸甲基酯、氯前列醇异丙基酯、15-酮-曲伏前列素、比马酰胺)的快速定性筛查方法。样品经乙腈超声提取,采用Waters ACQUITY UPLC BEH C18(2.1 mm×100 mm,1.7μm)色谱柱,以2 mmol/L甲酸铵水溶液(含0.05%甲酸)-乙腈为流动相,分离后进入四极杆飞行时间质谱,采用电喷雾离子源正离子模式(ESI+),以MSE模式进行数据采集,建立了9种前列腺素F2α类化合物的筛查数据库。9种化合物在各自质量浓度范围内线性关系良好,相关系数(r2)均大于0.99,检出限为0.075~0.75μg/g,定量下限为0.25~2.5μg/g。所建立的筛查数据库无需对照品即可对化妆品中的9种前列腺素F2α类化合物进行筛查。结果表明,该方法特异性良好,应用于48批睫毛类化妆品的定性筛查具有良好的选择性,可为化妆品中前列腺素F2α类化合物的筛查分析提供技术支... 相似文献
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Correlation between nodes is found to be a common and important property in many complex networks. Here we investigate degree correlations of the Barabasi-Albert (BA) scale-free model with both analytical results and simulations, and find two neighbouring regions, a disassortative one for low degrees and a neutral one for high degrees. The average degree of the neighbours of a randomly picked node is expected to diverge in the limit of infinite network size. As a generalization of the concept of correlation, we also study the correlations of other scalar properties, including age and clustering coefficient. Finally we propose a correlation measurement in bipartite networks. 相似文献
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本文简要地介绍了内蒙古广电双向网络的整体规划,介绍了CMTS—CM(大C)和OLT—CCMTS(小C)的各项指标设置并进行比较。 相似文献
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A high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)method was developed for the determination of perfluorooctane sulfonic acid (PFOS)in cosmetics. The cosmetic samples were extracted with methanol by ultrasonication,and PFOS was quantified by HPLC-MS/MS. The samples were detected in negative multiple reaction monitoring(MRM)mode using an Agilent Poroshell 120 EC-C18 (100 mm× 2.1 mm,2.7 µμm)column with a gradient elution using 0.1% formic acid aqueous solution(A)-methanol(B)as the mobile phase. The results showed that the linearity of PFOS was good in the range of 1-100 µμg/L with the correlation coefficient r2 larger than 0.9998;the limits of detection and limits of quantification were 0.015 and 0.050 mg/kg,respectively. The average recoveries were 98.7%-112.5%,and the relative standard deviations (RSDs)were less than 5%. The method is suitable for the determination of PFOS in cosmetics. © 2023, Youke Publishing Co.,Ltd. All rights reserved. 相似文献
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