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1.
为了探索生物化学、生物医学中混合寡肽的分析问题,对未衍生的混合二肽场解吸质谱进行了研究(图1和图2)。在图1图2中出现了所有二肽的准分子离子[M+H]~+,除此外还出现了[2M+H]~+、[M_(AB)+H]~+、[M_(AC)+H]~+等集聚离子,这些集聚离子能用于进一步确定各个肽的分子量。  相似文献   

2.
刺五加寡糖的电喷雾多级串联质谱研究   总被引:2,自引:0,他引:2  
采用小柱层析法从刺五加中分离得到刺五加寡糖类系列化合物(刺五加二糖刺五加六糖).实验结果表明,在正离子模式下的ESI-MS谱中,此类化合物呈现出特征的加合离子峰簇[M+Na]+/[M+K]+或[M+H2O+Na]+/[M+H2O+K]+,可以确定其分子量;在负离子模式下的ESI-MS谱中,刺五加寡糖易形成[M-H]-/[M+nH2O-H]-(n<3).还利用电喷雾多级串联质谱(ESI-MSn)对刺五加三糖进行了系统的研究,推断出刺五加三糖的组成与结构.  相似文献   

3.
本文阐述了几个寡肽的场解吸质谱。根据四个标准二肽场解吸质谱的裂解规律对四个合成肽进行了鉴定。这些肽的场解吸质谱不仅获得了高强度的分子离子M~+或[M+1]~+、[M+2]~+而且获得了部分序列信息。  相似文献   

4.
合成多肽的电喷雾质谱研究   总被引:3,自引:2,他引:1  
利用电喷雾多极串联质谱对3种合成多肽进行了系统的鉴定和分析研究。首先通过全扫描模式测定了其分子量,然后选择[M H]^ 或[M 2H]^2 离子通过串联质谱(MS/MS)得到碎片离子,采用y离子和b离子互补的方法测定了多肽序列。利用文献数据对这种方法进行了验证,实验结果表明,该方法简便、快速、实用。  相似文献   

5.
将大气压光电离(APPI)、电喷雾(ESI)、实时直接分析(DART)多种电离源和傅立叶变换离子回旋共振质谱(FT-ICR MS)联用对石油芳烃样品中的未知化合物进行研究。通过高分辨质谱的精确质量,结合碰撞诱导解离(CAD)技术,经分析并与文献标准物质谱图比对,推断未知物为三(2,4-二-叔丁基苯基)磷酸酯(TDTBPP),并研究了其在不同大气压电离源中的电离特性。APPI谱图中主要为[M+H]~+峰,同时存在M.~+峰。ESI谱图中主要为[M+Na]~+(不加甲酸)或[M+NH4]~+峰(加甲酸)。DART谱图中主要为[M+NH4]~+峰,而EI谱图中基峰为m/z 57(叔丁基),次强峰为[M-CH3]~+峰。  相似文献   

6.
聚芴类发光材料合成中间体的质谱分析   总被引:3,自引:2,他引:1  
利用电喷雾电离(ESI)质谱-质谱(MS-MS)技术,分析了新化合物2,7-双(4,4,5,5-四甲基-1,3,2-二氧杂硼烷-2-基)-9,9-二辛基芴的EI和ESI的质谱,确认了该谱图中母离子和子离子的关系,讨论了其碎裂途径,为其结构鉴定提供了依据。  相似文献   

7.
在不需要色谱分离的前提下,应用电喷雾电离-串联质谱法(ESI-MS/MS)对纺织品中偶氮染料还原产物4,4′-二氨基二苯醚进行测定。在MS/MS中,选择电喷雾离子源,以正离子扫描,选择离子监测模式和二级选择反应监测模式对4,4′-二氨基二苯醚进行定性和定量检测。以[M+H](m/z201)为母离子,选择其二级离子中碎片离子[M+H-NH3](m/z184)和[M+H-C6H7N](m/z108)为子离子。方法的检出限(19S/N)为70 ng.L-1。以1 ng.L-14,4′-二氨基二苯醚溶液进样2μL,平行测定9次,峰面积测定值的相对标准偏差为1.7%。  相似文献   

8.
利用超高效液相色谱-四极杆-飞行时间质谱(UPLC-QTOF-MS)的数据非依赖性采集(DIA)技术,结合靶向筛查方法,快速辨识芪玉三龙汤(Qi-Yu-San-Long decoction, QYSLD)化学成分。以Waters ACQUITY UPLC BEH C18柱(100 mm×2.1 mm, 1.7 μm)为色谱柱,流速为0.2 mL/min,柱温为35 ℃,进样量为2 μL,以0.1%(v/v)甲酸水溶液-乙腈为流动相进行梯度洗脱。采用电喷雾电离(ESI)源,以全信息串联质谱(MSE)技术在正、负离子模式下分别采集QYSLD复杂组分的质谱数据。通过检索文献和在线数据库,建立QYSLD中各单味药材化学成分库。将采集到的样品原始质谱数据与QYSLD化学成分库导入天然产物后处理筛查(UNIFI)平台;在UNIFI平台中设置参数(保留时间偏差为±0.1 min,精确质量数偏差阈值为±5×10-6,正离子模式下,选择[M+H]+和[M+Na]+为准分子离子或加合离子,负离子模式下,选择[M-H]-和[M+HCOO]-)。经UNIFI平台对MSE模式下采集的质谱数据与自建数据库中成分作靶向筛查,结合化合物准分子离子、质谱裂解途径及部分对照品进行结构确认。从QYSLD中共识别出166种化学成分,其中皂苷类22种,生物碱类13种,黄酮类27种,萜类32种,氨基酸类20种,苯丙素类16种,有机酸类9种,甾醇类6种,蒽醌类6种,其他类15种。其中16种成分使用对照品作验证。研究建立的方法能够快速、可靠的表征QYSLD中的化学成分,为该复方的药效物质及质量控制研究奠定了基础。  相似文献   

9.
陈学国  宋鸣  朱昱  吴迪  许英健 《分析测试学报》2013,32(10):1222-1226
建立了3种常见兴奋剂类毒品3,4-亚甲二氧甲基苯丙胺(MDMA)、甲基苯丙胺(MA)、可卡因及其代谢物同时分离与鉴定的液相色谱-电喷雾离子阱质谱(LC-ESI-ITMS)方法。通过体外代谢方法得到大鼠肝微粒体S9组分中MDMA、MA、可卡因及代谢产物混合体系后,利用LC-ESI-ITMS联用技术对各代谢物进行分析,得到各代谢物的[M+H]+分子量信息,进一步结合多级串联质谱(LC-MSn)分析结果获得结构信息,对代谢物进行鉴定,从而快速推测代谢物结构,得到MDMA、MA、可卡因的主要代谢产物。所建立的方法用于3种常见兴奋剂类毒品及其代谢物的分析,具有快速、高效、灵敏、选择性好等特点。  相似文献   

10.
建立了血液与尿液中麻黄碱和秋水仙碱的高效液相色谱-质谱联用(HPLC-MS)的同时测定方法。血液与尿液样品经三氟乙酸-乙腈(1∶99)溶液提取后,用Waters Oasis(MCX固相萃取小柱进行净化,在XDB-C8柱上以甲醇-0.04%(体积分数)三氟乙酸(33+67)为流动相,采用电喷雾电离(ESI)在选择离子监测(SIM)模式下测定。定量分析离子:麻黄碱(m/z)166[M+H]+;秋水仙碱(m/z)400[M+H]+。麻黄碱和秋水仙碱在4.0~1 000.0和6.0~1 000.0μg.L-1范围内均呈线性关系,检出限分别为4.0和6.0μg.L-1,回收率在81.0%~109.0%范围内,其日内精密度<6.4%,日间精密度<9.9%。  相似文献   

11.
Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.  相似文献   

12.
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.  相似文献   

13.
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   

14.
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   

15.
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   

16.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.  相似文献   

17.
The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.  相似文献   

18.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

19.
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   

20.
A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.  相似文献   

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