Kruve Anneli, Kaupmees Karl
Institute of Chemistry, University of Tartu, Ravila 14a, Tartu, 50411, Estonia.
J Am Soc Mass Spectrom. 2017 May;28(5):887-894. doi: 10.1007/s13361-017-1626-y. Epub 2017 Mar 15.
Adduct formation is a common ionization method in electrospray ionization mass spectrometry (ESI/MS). However, this process is poorly understood and complicated to control. We demonstrate possibilities to control adduct formation via mobile phase additives in ESI positive mode for 17 oxygen and nitrogen bases. Mobile phase additives were found to be a very effective measure for manipulating the formation efficiencies of adducts. An appropriate choice of additive may increase sensitivity by up to three orders of magnitude. In general, sodium adduct [M + Na] and protonated molecule [M + H] formation efficiencies were found to be in good correlation; however, the former were significantly more influenced by mobile phase properties. Although the highest formation efficiencies for both species were observed in water/acetonitrile mixtures not containing additives, the repeatability of the formation efficiencies was found to be improved by additives. It is concluded that mobile phase additives are powerful, yet not limiting factors, for altering adduct formation. Graphical Abstract ᅟ.
加合物形成是电喷雾电离质谱（ESI/MS）中一种常见的电离方法。然而，这个过程理解起来很困难且难以控制。我们展示了在ESI正模式下通过流动相添加剂控制17种氧和氮碱加合物形成的可能性。发现流动相添加剂是操纵加合物形成效率的一种非常有效的措施。选择合适的添加剂可使灵敏度提高多达三个数量级。一般来说，发现钠加合物[M + Na]和质子化分子[M + H]的形成效率具有良好的相关性；然而，前者受流动相性质的影响明显更大。尽管在不含添加剂的水/乙腈混合物中观察到这两种物质的形成效率最高，但发现添加剂可提高形成效率的重复性。得出的结论是，流动相添加剂对于改变加合物形成是强大的，但不是限制因素。图形摘要ᅟ 。
