基质与样品的相互作用对于傅立叶变换离子回旋共振质谱测定低分子量多肽的影响

通过比较两种极性差异较大的基质2,5-二羟基苯甲酸(DHB)和2’,6’-二羟基苯乙酮(DHAP)按不同比例混合时,AngiotensinⅡ的基质辅助激光解析电离-傅立叶变换离子回旋共振质谱(MALDI-FT/ICRMS)谱图的不同,并结合基质-AngiotensinⅡ在不同结晶方式下的共结晶和基质晶体的扫描电镜照片,发现基质为10μmol/L DHB和15μmol/L DHAP以体积比4:1组成的混合物时,基质结晶为致密的层状结构,而以薄层法与AngiotensinⅡ生成的共结晶,AngiotensinⅡ在基质晶体上面形成分散的柱状小晶体,此时得到的MALDI-FT/ICRMS质谱图优于干滴法。

Effect of Interaction of Matrix and Analyte on Detection of Low Molecular Weight Peptide by Matrix Assisted Laser Desorption Ionization-Fourier Transform/Ion Cyclotron Resonance Mass Spectrometry

Because of the suppression of 2′,6′-dihydroxyacetophenone(DHAP) to the combination of peptide with alkali metal ion and the advanced ability of 2,5-dihydroxybenzoic acid(DHB) to ionize peptide in MALDI-MS,it is illustrated in this work that the best MALDI-FT/ICRMS is obtained when matrix is composed of 10 μmol/L DHB and 15 μmol/L DHAP.The scanning electron microscope pictures of matrix with different compositions show that the crystal of matrix composed of 8 μmol/L DHB and 3 μmol/L DHAP is in a dense stratiform state that is quite different from crystal of matrix with other proportion of DHB and DHAP.It is also demonstrated that thin-layer method is the best peptide preparation method with matrix composed of 8 μmol/L DHB and 3 μmol/L DHAP among dry-droplet and sandwich method.