首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 140 毫秒
1.
选用液相基质制样,考察了激光强度、回旋池开门时间等因数对基质辅助激光解吸电离-傅里叶变换离子回旋共振质谱(MALDI—FT—ICR—MS)检测结果的影响,优化了实验条件。使用液相制样方法对5类实际样品进行了MALDI—FT-ICR—MS检测,结果表明:液相基质具有很好的通用性,质谱信号稳定、持久。利用FT-ICR—MS特有的超高分辨率与准确度,能够很准确地测定化合物组成。  相似文献   

2.
飞行时间质谱仪(TOFMS)在理论上无质量范围的限制,可实现大分子蛋白质与核酸的非共价复合物的直接检测.特别是在近中性溶液条件下通过对芥子酸和6-氮杂-2-硫代胸腺嘧啶基质的使用及双层样品制备方法的改善,获得了稳定复合物的高灵敏度质谱检测.肌红蛋白-血红素复合物能够在芥子酸基质的不同pH条件下(pH2.0或pH5.0)同时观察到.而运用双层样品制备方法,获得了核糖核酸酶复合物(RNaseS)在第一次激光照射下的突出质谱峰,但其丰度均随更多的激光打击而减弱.  相似文献   

3.
酶作为生物催化剂参与很多重要的生理过程,同时也是一类重要的生物分子。酶的活性分析对于疾病诊断和治疗具有重要意义。基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)具有操作简单、分析速度快、灵敏度高和易于实现高通量分析的特点,已被广泛用于各种组学研究和生物分子的检测,在酶的检测和活性分析中亦发挥了重要作用。该文综述了国内外利用MALDI-TOF MS分析酶活性和进行药物筛选的策略,总结了各种方法的优缺点,提出了MALDI质谱技术在酶活性分析领域存在的问题和挑战,并对其发展前景进行了展望。  相似文献   

4.
利用激光解吸电离傅立叶变换离子回旋共振质谱(Laser desorption ionization,LDI-FTICR-MS)建立了一种快速分析食用油中甘油三酯(TAG)的方法。在激光能量为45%,激光频率100 Hz和辐照次数100shots的条件下,可以获得稳定重复的信号(RSD10%)。通过TAG的一级质谱图和二级碎片信息可以初步区别不同类型的食用油。在置信度为95%条件下,利用主成分分析法和聚类分析法可以有效地将34种食用油归类。此外,利用该方法可直接识别橄榄油中掺杂5%的菜籽油且根据线性公式可初步预测橄榄油中掺杂油品的种类。分析数据表明,LDI-FTICR-MS技术具有快速筛查和识别食用油的潜力。  相似文献   

5.
MALDI质谱检测蛋白质与富勒醇的非共价复合物   总被引:4,自引:0,他引:4  
基质辅助激光解吸电离(MALDI)质谱由于受到酸性基质、样品制备、激光诱导聚合和基质加合物的形成等条件的限制而难以用于非共价复合物的检测.本文以芥子酸为基质,观察到蛋白质与富勒醇的特殊相互作用,一些质谱特征,如质量数迁移、宽的加合峰和定量结合比表明,在蛋白质和富勒醇之间形成了特殊的非共价复合物.其中,血红蛋白与富勒醇的结合比是1:4,而肌红蛋白与富勒醇的结合比是1:1.实验结果表明:富勒醇可用来保护血红蛋白,有在酸性介质中防止其分解的作用.因此,通过在基质组份中添加特性有机化合物保护被测样品,有可能实现用MALDI质谱测定四级结构蛋白质的分子量.  相似文献   

6.
蛋白质组学中基质辅助激光解吸电离的基质研究进展   总被引:1,自引:0,他引:1  
基质辅助激光解吸电离(MALDI)技术是近年来发展起来的新的质谱离子化技术。本文较为系统地综述了应用于蛋白质组学中的MALDI基质的最新进展以及不同的基质的优缺点及应用范围,并且归纳了其发展趋势。  相似文献   

7.
以常用于DNA分析的基质3-羟基吡啶甲酸(3-HPA),以及常用于高分子聚合物分析的基质2-(4-羟基苯基偶氮)苯甲酸(HABA)、反式-3-吲哚基丙烯酸(IAA)和1,8,9-三羟基蒽(Dithranol)为研究对象,考察了基质溶剂、浓度及激光强度对基质本身在激光解吸电离/质谱(LDI/MS)过程中产生基质簇峰的影响,对基质簇峰可能形成的过程进行了推测,并对各基质簇峰进行了归属,提出了基质簇离子峰m/z值遵循的计算公式。  相似文献   

8.
该文建立了一种利用基质辅助激光解吸电离-傅里叶变换离子回旋共振质谱(MALDI-FTICR-MS)快速测定全血及尿液中百草枯的分析方法。采用含1%甲酸的乙腈溶液从生物样品中提取百草枯,并与2,5-二羟基苯甲酸溶液混合后直接进样分析。结果表明,全血、尿液和水中的百草枯在10~5 000μg/L质量浓度范围内线性良好,相关系数(r)为0.995 5~0.999 2;3种基质下的方法检出限(LOD,S/N=3)为0.6~3.0μg/L,定量下限(LOQ,S/N=10)为2.0~10μg/L;百草枯在全血和尿液中的平均回收率为85.2%~110%,相对标准偏差(RSD)为0.40%~7.3%。该方法具有所需样品和溶剂用量少,操作简单,分析速度快,灵敏度高,且稳定可靠等特点,可满足临床及司法鉴定相关的中毒快检需求。  相似文献   

9.
该文基于基质辅助激光解吸电离-傅里叶变换离子回旋共振质谱技术(MALDI-FTICR-MS)建立了冬瓜、黄瓜、小白菜、上海青、韭菜、芹菜和生菜共7种蔬菜中百草枯和敌草快的快速测定方法.研究对比了低浓度2,5-二羟基苯甲酸(2,5-DHB)和α-氰基-4-羟基肉桂酸(CHCA)两种MALDI基质对百草枯和敌草快响应的影响...  相似文献   

10.
将离子液体2,5-二羟基苯甲酸丁胺用于改进基质辅助激光解吸电离质谱分析寡糖的定量重复性,并进一步用于大豆和豆叶中寡糖的质谱成像研究.实验中设定正电荷检测模式、激光能量为70%,采用将离子液体2,5-二羟基苯甲酸丁胺甲醇溶液(20%,V/V)直接覆盖样品的简单加基质方法,分析寡糖样品及大豆和豆叶寡糖分布的质谱成像.结果表明,离子液体2,5-二羟基苯甲酸丁胺作为基质,用基质辅助激光解吸电离化质谱分析蔗糖、棉子糖、水苏糖3种寡糖样品,点内重复性RSD<3%,点间重复性RSD<4%,在0.062~1.00 mg/mL 范围内测定的线性相关系数R2≥ 0.996,显示出较好的定量分析潜力.将此基质用于基质辅助激光解吸电离质谱成像分析大豆切片和豆叶表面的二糖、三糖和四糖,得到空间分辨率为150 μm的3种寡糖质谱成像图.3种寡糖在大豆中大致均衡分布,在豆叶的分布均以叶尖为多,并且根据标准曲线和图中的信号强度可以估计其含量.  相似文献   

11.
MALDI/FTMS质量校准新方法   总被引:2,自引:1,他引:2  
苏越  陈国强  郭寅龙  相秉仁  安登魁 《化学学报》2004,62(16):1551-1556
在MAIDL/FTMS质量校准中采用 mz =Af +Bf2 模型 ,通过基质峰的测定频率对模型中的参数A ,B进行调整 ,使模型参数更加接近测定状态 ,调整后模型的计算结果明显改善 ;并对多元回归和单纯形法两种建模方法以及单纯形法的目标函数进行了考察 ,结果表明以最大相对误差绝对值为目标函数的单纯形法建立的模型在预测离子质量方面具有较好的稳健性 ,质量测定相对误差均小于 5× 10 -6.用此法分析了克拉霉素的IRMPD质谱裂解规律 ,得到了合理的裂解规律  相似文献   

12.
The array of analytes that can be measured by MADLI MS has created an equally vast range of calibration mixtures. The inherent problem with this is that acquiring all of them at commercial rates can be prohibitively expensive. With this in mind, we have created a low‐cost alternative to the most commonly used peptide calibrants. We were able to achieve an overall 78 ppm mass accuracy across a mass range of 900 to 2500 Da which was comparable to the mass accuracy achievable with commercial peptide mixes and hence has become a viable alternative.  相似文献   

13.
各种野外环境的现场检测、现场诊断、流程监控、排放物检测与控制、突发事件的处理、尤其是化学和生物武器的检测等诸多需要现场使用质谱仪的场合都对质谱仪的小型化提出了迫切的要求。小型离子阱具有较高的灵敏度,可进行MS/MS实验,可利用离子-分子反应来识别特殊的化学基团,因而是小型质谱仪的重要质量分析器。本研究对小型离子阱的工作原理作了简要介绍,并以此为依据提出了进行小型离子阱质量校正的方法,推导了相关的公式,还成功地将其应用于自制的小型矩形离子阱质谱仪进行了质量校正,并指出该方法还可用于仪器RF等电学系统性能的检验。  相似文献   

14.
Described here is a computationally automated method for translating complex accurate mass spectra into biologically relevant and meaningful data. Rapid profiling of detailed high resolution mass spectra resulting from direct analysis of whole cells and tissues by matrix-assisted laser desorption/ionization (MALDI) Fourier transform mass spectrometry (FTMS) is discussed. Lipid and phospholipid ions create complex spectra containing multiple m/z values corresponding to the same fundamental chemical species. A computational approach is employed to sort ions, with mass to charge ratios lower than m/z 1000, into groups of similar lipid and phospholipid compositions for comprehensive and rapid analysis. By sorting or binning ions in this manner, variations in the degree of cation exchange can be avoided, thus increasing the comparability of the data. The result is displayed as a histogram that is easily interpretable and comparable with similar analyses and is particularly useful for direct comparison of similar tissues. Spectra of leaves from a healthy Prunus persica (peach) tree are compared with those from leaves infected by the fungus Taphrina deformans. Although the infection can be seen as a difference in leaf structure and by visual inspection of the mass spectra, the method described here details the chemical difference in phospholipid compositions and their relative abundances.  相似文献   

15.
Matrix-Assisted Laser Desorption/Ionization (MALDI) allows the identification of repeat units and end groups, the structural analysis of linear and cyclic oligomers, and the estimate of composition and sequence for copolymers. MALDI has also been applied to the measurement of molar mass distributions in polymers and to the study of thermal and oxidative processes in polymers. This paper illustrates the detection of self-association in macromolecules made by coupling MALDI and Size Exclusion Chromatography (SEC), the investigation of polymer oxidation phenomena, and the characterization of copolymers formed in the processing of reactive polymer blends.  相似文献   

16.
The specific matrix used in matrix‐assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) can have an effect on the molecules ionized from a tissue sample. The sensitivity for distinct classes of biomolecules can vary when employing different MALDI matrices. Here, we compare the intensities of various lipid subclasses measured by Fourier transform ion cyclotron resonance (FT‐ICR) IMS of murine liver tissue when using 9‐aminoacridine (9AA), 5‐chloro‐2‐mercaptobenzothiazole (CMBT), 1,5‐diaminonaphthalene (DAN), 2,5‐Dihydroxyacetophenone (DHA), and 2,5‐dihydroxybenzoic acid (DHB). Principal component analysis and receiver operating characteristic curve analysis revealed significant matrix effects on the relative signal intensities observed for different lipid subclasses and adducts. Comparison of spectral profiles and quantitative assessment of the number and intensity of species from each lipid subclass showed that each matrix produces unique lipid signals. In positive ion mode, matrix application methods played a role in the MALDI analysis for different cationic species. Comparisons of different methods for the application of DHA showed a significant increase in the intensity of sodiated and potassiated analytes when using an aerosol sprayer. In negative ion mode, lipid profiles generated using DAN were significantly different than all other matrices tested. This difference was found to be driven by modification of phosphatidylcholines during ionization that enables them to be detected in negative ion mode. These modified phosphatidylcholines are isomeric with common phosphatidylethanolamines confounding MALDI IMS analysis when using DAN. These results show an experimental basis of MALDI analyses when analyzing lipids from tissue and allow for more informed selection of MALDI matrices when performing lipid IMS experiments.  相似文献   

17.
Matrix‐assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) is a powerful molecular mapping technology that offers unbiased visualization of the spatial arrangement of biomolecules in tissue. Although there has been a significant increase in the number of applications employing this technology, the extracellular matrix (ECM) has received little attention, likely because ECM proteins are mostly large, insoluble and heavily cross‐linked. We have developed a new sample preparation approach to enable MALDI IMS analysis of ECM proteins in tissue. Prior to freezing and sectioning, intact tissues are decellularized by incubation in sodium dodecyl sulfate. Decellularization removes the highly abundant, soluble species that dominate a MALDI IMS spectrum while preserving the structural integrity of the ECM. In situ tryptic hydrolysis and imaging of tryptic peptides are then carried out to accommodate the large sizes of ECM proteins. This new approach allows the use of MALDI IMS for identification of spatially specific changes in ECM protein expression and modification in tissue. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

18.
19.
20.
MALDI mass spectrometry imaging (MSI) enables analysis of peptides along with histology. However, there are several critical steps in MALDI MSI of peptides, 1 of which is spectral quality. Suppression of MALDI matrix clusters by the aid of ammonium salts in MALDI experiments is well known. It is asserted that addition of ammonium salts dissociates potential matrix adducts and thereafter decreases matrix cluster formation. Consequently, MALDI MS sensitivity and mass accuracy increase. Up to our knowledge, a limited number of MALDI MSI studies used ammonium salts as matrix additives to suppress matrix clusters and enhance peptide signals. In this work, we investigated the effect of ammonium phosphate monobasic (AmP) as alpha‐cyano‐4‐hydroxycinnamic acid (α‐CHCA) matrix additive in MALDI MSI of peptides. Prior to MALDI MSI, the effect of varying concentrations of AmP in α‐CHCA was assessed in bovine serum albumin tryptic digests and compared with the control (α‐CHCA without AmP). Based on our data, the addition of AmP as matrix additive decreased matrix cluster formation regardless of its concentration, and specifically, 8 mM AmP and 10 mM AmP increased bovine serum albumin peptide signal intensities. In MALDI MSI of peptides, both 8 and 10 mM AmP in α‐CHCA improved peptide signals especially in the mass range of m/z 2000 to 3000. In particular, 9 peptide signals were found to have differential intensities within the tissues deposited with AmP in α‐CHCA (AUC > 0.60). To the best of our knowledge, this is the first MALDI MSI of peptides work investigating different concentrations of AmP as α‐CHCA matrix additive to enhance peptide signals in formalin‐fixed paraffin‐embedded (FFPE) tissues. Further, AmP as part of α‐CHCA matrix could enhance protein identifications and support MALDI MSI‐based proteomic approaches.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号