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There is increasing interest in the use of matrix-assisted laser desorption (MALDI) as an alternative to gel permeation chromatography (GPC),which is combined with FABMAS for synthetic polymer analysis. 相似文献
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葡聚糖的基体辅助激光解吸/电离飞行时间质谱测定 总被引:3,自引:0,他引:3
采用自行设计合成的新基体α-腈基阿魏酸(α-cyano-ferulic acid,简称CFA)并应用激光飞行时间质谱仪的离子偏转功能,对葡聚糖的分子量进行了测定研究。结果表明:与测定糖类物质的常用基体2,5-二羟基苯甲酸(DHB)相比,CFA测定葡聚糖,具有更佳的解吸电离效果,样品易出峰、重现性好、信噪比高;使用仪器的离子偏转器,阻止葡聚糖样品中聚合度较小的离子进入检测器,能显著提高仪器对聚合度较大离子的检测能力,得到质荷比(m/z)更高的质谱峰。 相似文献
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TSAO Rong 《高等学校化学研究》2010,26(1):11-16
A simple method was developed for rapid and direct profiling of alkaloids in medical herbs via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF MS). The dry herbs were first ground to powder and passed through a stainless steel sieve, mixed with the matrix solution to form a homogeneous suspension, which was then directly applied to MALDI analysis. Several matrices were investigated and 2,5-dihydroxybenzoic acid(DHB) was chosen as the optimized one, and the particle wit... 相似文献
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以微量HeLa细胞(107个)为对象, 经细胞裂解、还原羧甲基化、胰酶降解和Oasis-HLB柱提取分离得到总糖肽后, 用PNGase F酶解释放N-糖链. 对所得N-糖链用Sep-Pak C18柱纯化后进行完全甲基化衍生, 再采用基质辅助激光解吸电离-飞行时间质谱(MALDI-TOF MS)分析HeLa细胞表面N-糖链的结构轮廓. 结果表明, 在获得的34种N-糖链中, 除高甘露糖型、二天线、三天线、四天线和五天线等N-糖链外, 还出现了在某种程度上与肿瘤发生转移相关的特殊平分型和Lewis结构. 利用MALDI-TOF MS技术可快速分析微量癌细胞表面N-糖链的结构轮廓, 为进一步寻找肿瘤糖链标志物及肿瘤的早期预防诊断提供技术支持. 相似文献
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MALDI-TOF质谱表征聚芳醚酮环状低聚物及其组分分布 总被引:1,自引:0,他引:1
应用介质辅助激光解吸离子化飞行时间质谱(MALDI-TOFMS),以二羟基苯甲酸为介质、N2(337nm)为激光源,对两种聚芳醚酮环状低聚物的结构进行了确认,研究了环状低聚物不同聚合度组分的分布规律,并且与GPC质量分析法作了比较,实验结果表明,MALDI-TQF质谱是分析环状低聚物的准确、快速的工具之一. 相似文献
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Shin Hye Kim Jeongkwon Kim Dae Won Moon Sang Yun Han 《Journal of the American Society for Mass Spectrometry》2013,24(1):167-170
We report here that a commercial silicon-on-insulator (SOI) wafer offers an opportunity for laser desorption/ionization (LDI) of peptide molecules, which occurs directly from its flat surface without requiring special surface preparation. The LDI-on-SOI exhibits intact ionization of peptides with a good detection limit of lower than 20 fmol, of which the mass range is demonstrated up to insulin with citric acid additives. The LDI process most likely arises from laser-induced surface heating promoted by two-dimensional thermal confinement in the thin Si surface layer of the SOI wafer. As a consequence of the thermal process, the LDI-on-SOI method is also capable of creating post-source decay (PSD) of the resulting peptide LDI ions, which is suitable for peptide sequencing using conventional TOF/TOF mass spectrometry. 相似文献
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尿毒症被认为是因为患者肾衰而毒素在体内滞留所致^[1]。1972年Babb等^[2]提出“中分子假说”,认为分子量在300-2000范围内的中等分子量的物质是尿毒症的主要毒性物质。从此,人们作了大量的努力去分离和鉴定尿毒症中分子毒物。然而尿毒症中分子毒物的成分极其复杂^[3],从设定的中分子组分中分离得到的大都是些分子量小于800的小分子物质^[4]。因而对中分子假说一直存在争议^[5].我们对尿毒症患者及正常人的血清和尿液进行凝胶色谱分离,从尿毒症血清和尿液及正常人尿液中得到两个中分子峰A,B。将不同来源的A峰中的分子毒物进行离子交换色谱的分离和比较,得到了仅存在于尿毒症血清和正常人尿液的A-3亚峰,经脱盐和飞行时间质谱分析,确定了该组分内含有分子分别为839.69,1007.94,2015.16,16,873.69,1106.67和1680.28的6种化合物。 相似文献
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通过体外模拟新生儿消化道条件,用基质辅助激光解吸离子化飞行时间串联质谱法(MALDI-TOF/TOF)探究人乳β-酪蛋白消化后的多肽组.在离子源加速电压为20 kV,激光波长337 nm,激光频率200 Hz,离子延迟提取时间330 ns,质谱信号单次扫描累加2000次条件下,扫描质量范围m/z 500 ~ 5000的肽段.结果表明,消化后得到26个肽段,分子量集中在1000~4000Da.与已知功能的肽段序列进行对比,人乳β-酪蛋白在新生儿体外模型消化后未产生与已知功能的活性肽序列匹配的肽段,但发现9个肽前体,其中含4个血管紧张素转化酶(ACE)抑制肽前体,2个酪蛋白磷酸肽(CPP)前体,2个抗氧化肽前体,1个免疫活性肽前体,由酶切位点推测分析,肽前体可以继续在蛋白酶作用下转化为生物活性肽. 相似文献
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基质辅助激光解吸电离质谱分析糖类物质 总被引:1,自引:0,他引:1
基质辅助激光解吸电离质谱(MALDI-MS)是一种样品无需衍生、图谱解析简单、灵敏度高、快速便捷的分析生物样品结构的方法,已被广泛用于糖类物质的结构分析。此技术与HPLC、糖苷酶外切技术以及各种串联质谱等技术结合使用,可给出糖类物质详细的结构信息。本文介绍了基质辅助激光解吸(MALDI)离子化技术的原理、特点、与飞行时间质量分析器(TOF)联用时的相关技术和裂解方式,以及MALDI-MS在分析糖类物质时选用的基质、样品的制备、糖链碎片分析的方法和在不同糖型分析中的应用,展示了它的发展前景。随着MALDI对糖类物质分析时基质的改进、质谱分辨率的提高、质量检测范围的扩大,MALDI-MS技术必将成为糖类物质分析中强有力的工具。 相似文献
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George S. McLeod Jan Axelsson Ron Self Peter J. Derrick 《Rapid communications in mass spectrometry : RCM》1997,11(2):214-218
Two methods for the collection of capillary electrophoresis fractions for analysis by matrix-assisted laser desorption/ionization have been investigated; the first using a novel ion-porous joint design for dropwise fraction collection and the second, a process of electrospray deposition. Sensitivity, shot-to-shot reproducibility, effect of matrix preparation and influence of buffer additives encountered in micellar electrokinetic capillary chromatography (MECC) have been examined using a standard peptide, methionine enkephalin. The direct collection of droplets from the capillary outlet was found to give a superior signal intensity, whereas the electrospray method, in its first stage of development, suffered through dilution effects and excessively wide sample distribution. The target compound was successfully collected by electrospray deposition and results indicated that signal intensity and sample homogeneity would be enhanced if the sprayed output could be collected into the sample wells in its entirety. The advantage of using electrospray deposition for the preparation of matrix layers followed by direct droplet collection onto the electrosprayed matrix was clearly demonstrated by improvements in both sensitivity and shot-to-shot variance in signal intensity across the sample well compared with collection onto spotted matrix. In addition, compatibility of the droplet collection method with MECC was illustrated by the recovery of the compound of interest from a buffer containing 30 mm sodium dodecyl sulphate. © 1997 John Wiley & Sons, Ltd. 相似文献