共查询到20条相似文献,搜索用时 46 毫秒
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以化妆品中23种防腐剂检测方法为例,探讨色谱柱选择对液相色谱方法测定结果的影响。参照《化妆品安全技术规范》甲基异噻唑啉酮等23个组分的检验方法,在2台不同的高效液相色谱仪上用15款不同品牌、型号的C18色谱柱检测23种防腐剂,计算色谱峰的理论塔板数和分离度,对23种组分的分离效果进行分析,并应用USP (United States Pharmacopeia)数据库和PQRI (Product Quality Research Institute)数据库等2种等效色谱柱选择方法,对不同色谱柱的分离效果及等效性进行评价和预测。实验结果表明,15款色谱柱对23种防腐剂的分离效果差异显著,仅有2款色谱柱可以实现23种组分的完全分离。USP和PQRI数据库中2种等效色谱柱选择方法均无法预测出合适的等效色谱柱,对23种防腐剂的液相色谱分析参考价值均较小。色谱柱是影响23种防腐剂液相色谱法测定结果准确性的关键因素,有关实验室在应用该方法时,应考虑色谱柱选择性差异。化妆品基质复杂,如何在现有研究成果的基础上,开发色谱柱的筛选和预测评价体系,进而指导实际样品的分离是下一步研究的重点、难点。建议有关部门在制修订检测方法时,注重色谱柱的耐用性考察,完善系统适应性指标,细化色谱柱分类和增加描述信息,指导色谱柱的合理选择,从而规避由于色谱柱使用过程中选择依据缺失而导致测定结果不准确的风险。 相似文献
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本文评述了固定酶柱后反应器在高效液相色谱中的应用。阐述了高效液相色谱与固定酶柱后反应器联用的原理,介绍了固定酶柱后反应器的主要类型。评述了固定酶柱后反应器在生化分析和临床分析中的应用。引文43篇。 相似文献
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纳流液相色谱是高效液相色谱微型化的重要形式,由于其具有溶剂消耗少、样品需求量小、检测灵敏度高以及与质谱联用兼容性好等特点,在生命科学、生物医药以及微纳分析等领域得到越来越广泛的应用。填充柱是最常用的纳流色谱柱类型,通常由球形色谱填料颗粒填充入毛细管内制成。样品组分是在色谱柱上实现分离,色谱柱的性能对色谱分析的选择性和分辨率至关重要,因此制备高质量的纳流色谱填充柱对获得高效的纳流液相色谱分离尤为关键。纳流色谱柱的制备包含两个重要技术环节:柱塞技术和填充工艺。近年来,随着柱塞与填充技术的进步,填充型纳流液相色谱柱的稳定性和分离性能得到了显著提升。本文对近十年来纳流液相色谱柱技术的研究进展,主要是柱塞技术和填充技术的研究和应用进展进行了概述,介绍了其在组学研究和生物制药领域中的应用,并对其发展前景进行了展望。 相似文献
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高效液相色谱整体柱技术的进展 总被引:1,自引:0,他引:1
高效液相色谱整体柱(又名连续床)具有制备相对简单、原料易得以及聚合组分在一定范围内可调节的优点,是近年来得到迅速发展的新型色谱柱。本文综述了目前高效液相色谱(HPLC)制备整体柱的典型高聚物体系、制备各种整体柱时反应条件的影响,并简要介绍了它的表征方法和应用。 相似文献
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Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives. 相似文献
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The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion. 相似文献
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N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%). 相似文献
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Shashikant U. Dighe Surya K. Samanta Shivalinga Kolle Sanjay Batra 《Tetrahedron》2017,73(17):2455-2467
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones. 相似文献
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In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates. 相似文献
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An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions. 相似文献
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Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described. 相似文献
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用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在. 相似文献
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An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction. 相似文献
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The Diels-Alder reactivity of 1,2-heteroborines (H4C4B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed. 相似文献