基体溶液pH值对基体辅助激光解吸电离质谱法测定结果的影响

研究了基体溶液的ｐＨ值对基体辅助激光解吸电离（ＭＡＬＤＩ）的影响，测定了从强酸至强碱不同ｐＨ值的α－氰基，４－羟基肉桂酸水溶液的紫外吸收谱，并分别用作基体测定细胞色素Ｃ的相对分子质量。结果显示除按常规配制的基体溶液（ｐＨ＝２．５）在激光波长３５５ｎｍ处有强紫外吸收外，其他ｐＨ＝１．０、ｐＨ＝８．０、ｐＨ＝１０．０的溶液皆没有吸收，而相对分子质量测量结果是ｐＨ＝１．０和ｐＨ＝２．５两种溶液可得到质量     

3—羟基—4—甲氧基肉桂酸——基体辅助激光解吸电离质谱法测定DNA的有 …

报家长在体辅助激光解吸电离质谱法（ＭＡＬＤＩ－ＭＳ）测定ＤＮＡ分子的一种有效基体３－羟基－４－甲氧基肉桂酸。实验发现该基体对ＤＮＡ分子解吸和电离效率高,对ＤＮＡｄ（Ｔ）１０分子离子峰的分辨率为５５５１．４倍,噪比为１１．８。３－羟基－４－甲氧基肉桂酸是ＭＡＬＤＩ－ＭＳ法测定ＤＮＡ分子的一个可供选择使用有效基体。     

基体辅助激光解吸/电离质谱法对核酸分子的分析测定

基体辅助激光解吸／电离质谱（ＭＡＬＤＩＭＳ）法自８０年代末由Ｋａｒａｓ,Ｈｉｌｅｎｋａｍｐ报道以来,已获得极大的发展．近几年来,其应用范围迅速扩大,各种生物大分子如蛋白质,核酸（ＤＮＡ）,多糖等都已能用ＭＡＬＤＩＭＳ法进行分子量测定．１９９３年,...     

基体辅助激光解吸电离质谱法对DNA样品的高分辨率测定

基体辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)法因其具有测定质量范围大、灵敏度高、速度快及精确度好等优点,近年来已成为测定多肽、蛋白质、核酸、多糖等生物大分子分子量及其一级结构的有力工具.     

基体溶液pH值对基体辅助激光解吸电离质谱法测量结果的影响

研究了基体溶液的ｐＨ值对基体辅助激光解吸电离（ＭＡＬＤＩ）的影响，分别测定了从强酸至强碱不同ｐＨ值的α－氰基，４－羟基肉桂酸水溶液的紫外吸收谱，并分别用作基体测定细胞色素Ｃ的相对分子质量。结果显示除按常规配制的基体溶液（ｐＨ＝２５）在激光波长３５５ｎｍ处有强紫外吸收外，其他ｐＨ＝１０、ｐＨ＝８０、ｐＨ＝１００的溶液皆没有吸收，而相对分子质量测定结果是ｐＨ＝１０和ｐＨ＝２５两种溶液可得到质量良好的谱图。而ｐＨ＝８０和１００的两种溶液则得不到谱图，作者还以溶液化学规律，及基体辅助激光解吸电离的机理，对结果进行了讨论。     

2-氨基-5-硝基吡啶在基体辅助激光解吸/电离质谱法测定核酸分子中的应用

报道以2-氨基-5-硝基吡啶为基体用基体辅助激光解吸/电离质谱法(MALDI-MS)对DNA样品进行测定并研究它们的激光质谱特征,结果表明,2-氨基-5-硝基吡啶是DNA的一高效基体.用柠檬酸铵和NH_4~+阳离子交换树脂除去试剂和样品中的碱金属离子,能显著地提高解吸/电离DNA分子的效率.     

基体辅助激光解吸电离飞行时间质谱分析糖类的基体

糖类物质极性高、难挥发、热不稳定,其中多糖还具有相对分子质量分布发散的性质,其质谱表征比较困难。基体辅助激光解吸电离飞行时问质谱(matrix-assisted lazer desorption／ionization time-of-flight mass spectrometry．MALDI-TOFMS)灵敏、快速,对杂质的包容性强、分析的质量范围大,能够对糖类尤其是非衍生化糖进行直接分析。近年来,MALDI-TOFMS的发展已使糖类物质的分析达到一个新的水平。由于基体在MALDI-TOFMS分析中起着至关重要的作用,而研制开发和使用各种有效新基体也一直是MALDI-TOFMS分析的聚焦点,本文综述近10年MALDI-TOFMS分析糖类所用的基体。     

基体辅助激光解吸电离飞行时间质谱用于寡糖的分析

将基体辅助激光解吸电离飞行时间质谱这种新兴的质谱方法用于植物中寡糖的分析。比较了不同的样品制备方法和检测方法对分析结果的影响,给出各寡糖样品的分子量分布,单体和端基基团的分子量。     

基体辅助激光解吸电离飞行时间质谱用于人参皂甙Rg3的定量分析

考察了基体辅助激光解吸电离时间飞行质谱用于人参皂甙Rg3 定量分析时内标的选择。加入棉子糖作为内标时 ,Rg3 的定量标准曲线的回归系数R2 =0 .938,平均相对误差为 2 8 6 % ;加入性质相近的芦丁后 ,Rg3 的定量标准曲线的回归系数R2 =0 993,平均相对误差为 7 5 %。分辨率的提高以及采用Rg3 和内标物的质谱峰的相对面积来代表Rg3 的浓度可以使定量的重现性明显改善     

基体辅助激光解吸/电离质谱测定小相对分子质量物质的方法进展

MALD I-MS分析具有高灵敏度、高分辨率、高质量准确度、制样快速、操作简单及高通量等优点,具有使各种不同类型物质离子化的能力。目前已广泛应用于化学、化工、材料、环境、地质、能源、刑侦、药物、生命科学等领域中。MALD I-MS最早主要用于分析各种生物大分子及聚合物。近年     

基体辅助激光解吸—电离飞行时间质谱法分析衍生化的寡链糖

以２，５－二羟基苯甲酸（ＤＨＢ）＋间硝基苄醇（ＮＢＡ）混合基体辅助激光解吸电离飞行时间质谱法（ＭＡＬＤＩ）分析甲壳素降解并衍生化的寡链糖，获得了满意的结果。对比其它基体，如：芥子酸（ＳＡ）、α－氰基－４－羟基肉桂酸等（α＿ＣＨＣＡ），２，５＿ＤＨＢ＋ＮＢＡ混合基体解吸电离效果最好：信号强、信噪比高。甲壳素降解产物的质谱分析至今未见报道。     

基体辅助激光解吸电离飞行时间质谱及其在高分子量物质测定中的应用

对基体辅助激光解吸电离飞行时间质谱这种新兴的质谱技术的原理及其在蛋白质序列分析、免疫分析、蛋白质定量和聚合物分子量分布的测定等方面的应用做了评述。引用参数文献５９篇。     

基质辅助激光解吸电离质谱的离子化机理

作为一种新兴的质谱技术,基质辅助激光解吸电离(MALDI)质谱近年来仪器研制和技术应用发展得非常之快,但是对于MALDI的离子化机理却众说纷纭,了解不深.虽然发展了一些理论,但由于MALDI机理的复杂性,譬如基质的选择、甚至溶剂的选择、结晶速度的快慢、浓度的大小、基质与样品的比例、制样方法等对最终结果都有显著的影响,所以质谱学术界尚未能得到1个统一的认识.纵观目前众多个研究者的看法,基本上可初步分为初次离子化和二次离子化机理两大类.初级离子化机理基于样品分子直接离子化考虑问题.样品吸收光子能量,直接失去电子,形成离子.但是单光子电离机理从能量上考虑似乎不大可能,因为1个光子所具有的能量,远小于生成1个离子需要的能量.多光子电离虽是1种最直接的解释:     

高电压辅助激光解吸附离子化质谱中盐效应的研究

通过与电喷雾质谱( Electrospray ionization mass spectrometry, ESI-MS)对比的方式,对高电压辅助激光解吸附离子化质谱( High-voltage-assisted laser desorption ionization mass spectrometry,HALDI-MS)中的盐效应进行了研究。在正、负离子模式下,分别以L-酪氨酸、β-环糊精、α-硫辛酸以及α-硫辛酸-β-环糊精复合体系为例,对比分析了加盐前后所得的ESI-MS和HALDI-MS谱图,发现HALDI-MS比ESI-MS具有更高的盐容忍度。本实验还发现在HALDI-MS中加入适量盐会引起α-硫辛酸与β-环糊精络合离子信号增强的特殊现象,并提出了产生这种信号增强作用的原因是溶液中盐类阳离子与α-硫辛酸-β-环糊精复合体系形成了三元复合物。     

Imaging of Phospholipids in Formalin Fixed Rat Brain Sections by Matrix Assisted Laser Desorption/Ionization Mass Spectrometry

Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a valuable tool for the analysis of molecules directly from tissue. Imaging of phospholipids is gaining widespread interest, particularly as these lipids have been implicated in a variety of pathologic processes. Formalin fixation (FF) is the standard protocol used in histology laboratories worldwide to preserve tissue for analysis, in order to aid in the diagnosis and prognosis of diseases. This study assesses MALDI imaging of phospholipids directly in formalin fixed tissue, with a view to future analysis of archival tissue. This investigation proves the viability of MALDI-MSI for studying the distribution of lipids directly in formalin fixed tissue, without any pretreatment protocols. High quality molecular images for several phosphatidylcholine (PC) and sphingomyelin (SM) species are presented. Images correspond well with previously published data for the analysis of lipids directly from freshly prepared tissue. Different ionization pathways are observed when analyzing fixed tissue compared with fresh, and this change was found to be associated with formalin buffers employed in fixation protocols. The ability to analyze lipids directly from formalin fixed tissue opens up new doors in the investigation of disease profiles. Pathologic specimens taken for histologic investigation can be analyzed by MALDI-MS to provide greater information on the involvement of lipids in diseased tissue.     

用MALDI-TOFMS观察适配子与炭疽芽孢的结合反应

用基质辅助激光解吸电离－飞行时间质谱（MALDI－TOF MS）观察炭疽芽孢适配子与炭疽芽孢结合反应，将SELEX（system evolution of ligands by exponential enrichment）技术筛选获得的一个炭疽芽孢适配子F77和第18轮的混合适配子以及兔抗炭疽芽孢抗体分别与炭疽芽孢结合反应后，用MALDI－TOF MS指纹图变化来研究这些分子与芽孢的结合情况，结果显示抗体、单体和混合适配子与芽孢结合反应后约在m/z1800处产生的质谱峰强度与芽孢对照相比明显降低；用MALDI－TOF MS质谱图变化可以推测适配子与芽孢的结合反应，该试验中观察到的结合情况与作者以前的研究结果一致。     

Analysis and Quantitation of Glycated Hemoglobin by Matrix Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry

Measurement of glycated hemoglobin is widely used for the diagnosis and monitoring of diabetes mellitus. Matrix assisted laser desorption/ionization (MALDI) time of flight (TOF) mass spectrometry (MS) analysis of patient samples is used to demonstrate a method for quantitation of total glycation on the β-subunit of hemoglobin. The approach is accurate and calibrated with commercially available reference materials. Measurements were linear (R² > 0.99) across the clinically relevant range of 4% to 20% glycation with coefficients of variation of ≤ 2.5%. Additional and independent measurements of glycation of the α-subunit of hemoglobin are used to validate β-subunit glycation measurements and distinguish hemoglobin variants. Results obtained by MALDI-TOF MS were compared with those obtained in a clinical laboratory using validated HPLC methodology. MALDI-TOF MS sample preparation was minimal and analysis times were rapid making the method an attractive alternative to methodologies currently in practice.

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Enrichment and Identification of Metallothionein by Functionalized Nano-Magnetic Particles and Matrix Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry

As a low molecular weight protein with the ability of binding metal ions and high inducibility, metallothionein (MT) is often regarded as an important biomarker for assessment of heavy metal pollution in water environment. In the light of that the traditional process of enrichment and identification is time-consuming and complicated, we prepared a core-shell nanoparticle, gold-coated iron oxide nanoparticles (Fe₃O₄@Au NPs) herein. It possessed the advantages of fast response to magnetic fields and optical properties attributing to Fe₃O₄ and Au nanoparticles, respectively. The Fe₃O₄@Au nanoparticles could be used to enrich MT simply through Au–S interaction, and the purified proteins were determined by matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/MS). The results showed that the Fe₃O₄@Au nanoparticles could directly enrich MT from complex solutions and the detection limit could be as low as 10 fg mL^?1.