以2-氨基-5-硝基噻唑为基质辅助激光解吸/电离飞行时间质谱的有效基质分析DNA及蛋白质样品

采用碱性新基质2-氨基-5-硝基噻唑对DNA和蛋白质样品进行了基质辅助激光解吸/电离飞行时间质谱分析.结果表明,2-氨基-5-硝基噻唑能有效地解吸电离DNA和蛋白质样品.采用正离子检测模式,分析分子量小于5000的pd(T)₁₀,pd(C)₁₀,pd(A)₈,pd(G)₁₀和pd(5′ATCGATCGAT3′)DNA样品时,分辨率均可达到1万以上;与分析DNA样品的常用基质相比,2-氨基-5-硝基噻唑解吸/电离样品分子所需要的激光强度小,易于获得信噪比和分辨率高及重复性好的谱图;分析蛋白质胰岛素、细胞色素C及牛血清白蛋白样品能达到与α-氰基-4-羟基肉桂酸(HCCA)和3,5-二甲氧基-4-羟基肉桂酸(SA)相同的效果.采用负离子检测模式则能以较高的信噪比获得分子量达到7000的DNA的分子离子峰信号.此外,以2-氨基-5-硝基噻唑为基质的基质辅助激光解吸/电离(MALDI)测定还表现出一定的耐盐能力.

Analysis of Oligonucleotide and Protein via Matrix-assisted Laser Desorption/Ionization Time-of-flight Mass Spectrometry Using 2-Amino-5-nitrothiazole as an Effective Matrix

Using 2-amino-5-nitrothiazole as a matrix, the matrix-assisted laser desorption/ionization time-of-flight mass spectrometric study of oligonucleotide and protein was carried out. The results show that 2-amino-5-nitrothiazole has a high efficiency in desorbing and ionizing oligonucleotide and protein molecules. In the positive-ion mode, resolution over 10 000 of pd(T)10, pd(C)10, pd(A)8, pd(G)10 and pd(5′ATC GAT CGA T 3′) can be obtained; 2-amino-5-nitrothiazole is as effective as the commonly used matrices such as α-cyano-4-hydroxycinnamic acid(HCCA) and 3, 5-dimethoxy-4-hydroxycinnamic acid(SA) for the analysis of proteins. In the negative-ion mode, the molecular ion signal of oligonucleotide with molecular mass of over 7 000 can be recorded at a high signal-to-noise ratio. Moreover, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF-MS) analysis by utilizing 2-amino-5-nitrothiazole as a matrix shows the tolerance to alkali metal cations to a certain extent.