Time-of-flight secondary ion mass spectrometry using a new primary ion beam generated by vacuum electrospray of a protic ionic liquid, propylammonium nitrate
Time-of-flight secondary ion mass spectrometry using a new primary ion beam generated by vacuum electrospray of a protic ionic liquid, propylammonium nitrate
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使用质子离子液体硝酸丙铵真空电喷雾产生的新初级离子束进行飞行时间二次离子质谱分析
DOI：
10.1002/rcm.7960
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发表时间：
2017
影响因子：
2
通讯作者：
Saito Naoaki
中科院分区：
文献类型：
--
作者：
Fujiwara Yukio;Saito Naoaki
在质子化方面，质子化离子液体具有作为初级离子束的有用材料的潜力，因为它们具有活性质子。选择适合于一次离子束的质子型离子液体对于提高分子二次离子产率具有重要意义。硝酸丙铵([C_3H_7NH_3][NO_3])是一种很有前途的质子亲和性化合物。[C3H7NH3]+离子可能是质子供体，[NO3]−阴离子可能是质子受体。用真空电喷雾产生初级丙基硝酸铵团簇离子束，用于氨基酸(精氨酸、谷氨酸、天冬氨酸)、血管紧张素II和聚乙二醇的分析。结果硝酸丙铵团簇离子束在阳离子模式下成功地产生了所有分析物的质子化分子[M~+~+~H]~+。初级离子束还以负离子模式产生谷氨酸、天冬氨酸和血管紧张素II的去质子化分子[M-−-H]−。此外，在精氨酸和聚乙二醇的情况下，还检测到与[C3H7NH3][NO3]有关的加合离子。结论TOF-SIMS实验证实，丙基硝酸铵团簇离子束可以有效地产生分子二次离子，表明它非常适合作为TOF-SIMS中的一次离子束。
RationaleProtic ionic liquids have the potential to be useful materials for primary ion beams in terms of protonation, since they have active protons. Selecting protic ionic liquids suitable for primary ion beams is of great importance to increase molecular secondary ion yields. Propylammonium nitrate ([C3H7NH3][NO3]) seems promising in view of its proton affinity. It is likely that [C3H7NH3]+cations can act as proton donors, and [NO3]−anions can work as proton acceptors.MethodsTime‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) experiments have been performed to verify the usefulness of [C3H7NH3][NO3]. A primary propylammonium nitrate cluster ion beam was generated by vacuum electrospray, and then used to analyze amino acids (arginine, glutamic acid, aspartic acid), angiotensin II and polyethylene glycol. Positive and negative secondary ion mass spectra were obtained to study both protonation and deprotonation.ResultsThe propylammonium nitrate cluster ion beam successfully generated protonated molecules [M + H]+of all the analytes in positive ion mode. The primary ion beam also generated deprotonated molecules [M − H]−of glutamic acid, aspartic acid and angiotensin II in negative ion mode. Additionally, adduct ions related to [C3H7NH3][NO3] were detected in the case of arginine and polyethylene glycol.ConclusionsThe TOF‐SIMS experiments confirmed that the propylammonium nitrate cluster ion beam was useful in generating molecular secondary ions, demonstrating that it is well suited for a primary ion beam in TOF‐SIMS.