UTILITY OF ORGANIC-BASES FOR IMPROVED ELECTROSPRAY MASS-SPECTROMETRY OF OLIGONUCLEOTIDES
UTILITY OF ORGANIC-BASES FOR IMPROVED ELECTROSPRAY MASS-SPECTROMETRY OF OLIGONUCLEOTIDES
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DOI：
10.1002/rcm.1290090121
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发表时间：
1995-01-01
影响因子：
2
通讯作者：
GRIFFEY, RH
中科院分区：
文献类型：
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作者：
GREIG, M;GRIFFEY, RH
当低聚物在气相中被钠或钾等阳离子内合时，使用电喷雾电离进行寡核苷酸质谱分析的灵敏度和准确性会受到损害。我们已经评估了添加一系列有机碱的mM浓度，溶液pK(b)值在11.5到5.5之间，气相质子亲和范围在213到232千卡/摩尔之间，作为一种抑制碱加合离子信号的方法。较强的碱基如三乙胺和哌啶能最有效地减少结合钠的信号，但也能降低寡核苷酸的总离子电流。咪唑溶液pH值接近8.0，对钠/钾加合物离子有适度的抑制作用，但灵敏度提高了4倍。咪唑和三乙胺或哌啶的加入对未通过初步沉淀或高效液相色谱脱盐的磷酸二酯或硫代低聚物样品产生高离子丰度和良好的阳离子加合物抑制作用。高浓度咪唑的加入产生了电荷态的双峰分布，这可能反映了单链低聚物的不同气相构象。
The sensitivity and accuracy of the mass spectrometric analysis of oligonucleotides using electrospray ionization can be compromized when the oligomer is adducted in the gas phase to cations such as sodium or potassium. We have evaluated the addition of mM concentrations of a series of organic bases with solution pK(b) values ranging from 11.5 to 5.5 and gas-phase proton affinities ranging from 213 to 232 kcal/mol as a method for suppression of signals from alkali-adducted ions. Stronger bases such as triethylamine and piperidine reduce the signals from bound sodium most effectively, but also decrease the total ion current from oligonucleotide. Imidazole, with a solution pH of similar to 8.0, provides modest suppression of sodium/potassium adduct ions, but up to a four-fold improvement in sensitivity. Go-addition of imidazole and triethylamine or piperidine produces high ion abundance and good suppression of cation-adducted species for samples of phosphodiester or phosphorothioate oligomers which have not been desalted via preliminary precipitation or by high-performance liquid chromatography. Addition of high concentrations of imidazole generates a bimodal distribution of charge states, which may reflect different gas-phase conformations for single-stranded oligomers.