Manier M Lisa, Cornett D Shannon, Hachey David L, Caprioli Richard M
Department of Chemistry, Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-8575, USA.
J Am Soc Mass Spectrom. 2008 May;19(5):666-70. doi: 10.1016/j.jasms.2008.01.015. Epub 2008 Feb 8.
Chemical contamination can be one of the more common problems encountered when performing trace-level analysis regardless of the analytical technique. Minimizing or eliminating background interferences can be a difficult task, so knowledge of the chemical composition of these contaminants can prove invaluable when it comes to identifying the source. Once the source is identified, proper steps may be taken to reduce or eliminate it. In this study, we report the identity of some commonly seen contaminants (m/z 550.6, 522.6, and 494.6) in electrospray ionization (ESI) mass spectrometry (MS). Through MS, tandem MS, accurate-mass, and high-resolution measurements we have identified these background contaminants as being quaternary ammonium species that contain long-chain hydrocarbon groups, where m/z 550.6 is a dimethyldioctadecylammonium ion (C(18), C(18)) and m/z 522.6 and 494.6 are similar in nature but have shorter alkyl-chain groups. The lipophilic nature of these compounds and the fact that they have molecular weights similar to lysophospholipids make them a frequent contaminant in lipidomic studies. The likely sources of these compounds are commonly used personal and household products.
无论采用何种分析技术，化学污染都可能是进行痕量分析时遇到的较为常见的问题之一。尽量减少或消除背景干扰可能是一项艰巨的任务，因此，了解这些污染物的化学成分在确定其来源时可能具有极高的价值。一旦确定了来源，就可以采取适当措施来减少或消除它。在本研究中，我们报告了电喷雾电离（ESI）质谱（MS）中一些常见污染物（质荷比为550.6、522.6和494.6）的身份。通过质谱、串联质谱、精确质量和高分辨率测量，我们已将这些背景污染物确定为含有长链烃基的季铵类物质，其中质荷比550.6是二甲基二辛基铵离子（C(18)，C(18)），质荷比522.6和494.6性质相似，但烷基链较短。这些化合物的亲脂性以及它们的分子量与溶血磷脂相似，这使得它们成为脂质组学研究中常见的污染物。这些化合物的可能来源通常是常用的个人护理和家用产品。
