There are two challenges in oligonucleotide detection by liquid chromatography coupled with mass spectrometry (LC-MS), the serious ion suppression effects caused by ion-pair reagents and the low detection sensitivity in positive mode MS. In this study, highly concentrated alcohol vapors were introduced into an enclosed electrospray ionization chamber, and oligonucleotides could be well detected in negative mode MS even with 100 mM triethylammonium acetate (TEAA) as an ion-pair reagent. The MS signal intensity was improved 600-fold (for standard oligonucleotide dT15) by the isopropanol vapor assisted electrospray, and effective ion-pair LC separation was feasibly coupled with high-sensitive MS detection. Then, oligonucleotides were successfully detected in positive mode MS with few adducts by propanoic acid vapor assisted electrospray. The signal intensity was enhanced more than 10-fold on average compared with adding acids into the electrospray solution. Finally, oligonucleotides and peptides or histones were simultaneously detected in MS with little interference with each other. Our strategy provides a useful alternative for investigating the biological functions of oligonucleotides.

中文翻译：

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通过有机蒸汽辅助电喷雾增强寡核苷酸检测的质谱灵敏度

液相色谱-质谱联用（LC-MS）进行寡核苷酸检测存在两个挑战，离子对试剂引起的严重离子抑制效应和正模式MS的低检测灵敏度。在这项研究中，将高浓度的乙醇蒸气引入封闭的电喷雾电离室，即使使用100 mM乙酸三乙铵（TEAA）作为离子对试剂，也可以在负模式MS中很好地检测到寡核苷酸。异丙醇蒸气辅助电喷雾将MS信号强度提高了600倍（对于标准寡核苷酸dT15），有效的离子对LC分离与高灵敏度MS检测相结合。然后，通过丙酸蒸气辅助电喷雾成功地在具有少量加合物的正模式MS中成功检测到寡核苷酸。与在电喷雾溶液中添加酸相比，信号强度平均提高了10倍以上。最后，在MS中同时检测到寡核苷酸，肽或组蛋白，彼此之间几乎没有干扰。我们的策略为研究寡核苷酸的生物学功能提供了有用的替代方法。