Biological Separations and Mass Spectrometry Group, Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
Rapid Commun Mass Spectrom. 2011 May 30;25(10):1452-6. doi: 10.1002/rcm.5017.
Two unexpected singly charged ions at m/z 1103 and 944 have been observed in mass spectra obtained from electrospray ionization mass spectrometric analysis of liquid chromatography effluents with mobile phases containing trifluoroacetic acid (TFA) that severely interfered with sample analysis. Accurate mass measurement and tandem mass spectrometry studies revealed that these two ions are composed of three components; clusters of trifluoroacetic acid, clusters of mass 159 and iron. Formation of these ions is inhibited by removing TFA from the mobile phases and using formic acid in its place, replacing the stainless steel union with a titanium union or by adding a small blank fused-silica capillary column between the chromatography column and the electrospray tip via a stainless steel union without any adverse effects to chromatographic separation, peak broadening or peptide identifications.
已观察到在含有三氟乙酸 (TFA) 的流动相的电喷雾电离质谱分析的液相色谱流出物的质谱中出现两个意想不到的单价离子，其质荷比 m/z 分别为 1103 和 944，这严重干扰了样品分析。精确质量测量和串联质谱研究表明，这两个离子由三个组成部分组成;三氟乙酸簇、质量为 159 的簇和铁簇。通过从流动相中去除 TFA 并用甲酸代替它、用钛接头代替不锈钢接头或通过在色谱柱和电喷雾尖端之间通过不锈钢接头添加一小段空白熔硅毛细管柱来抑制这些离子的形成，而不会对色谱分离、峰展宽或肽鉴定产生任何不利影响。
