Annotation of fragment ions from stable isotope-labeled lipids.

Abstract

<p>A) Positive FTMS² spectrum of protonated PC 34:2(+[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0188394#pone.0188394.ref002" target="_blank">2</a>]H13). The fragment ions identify the molecular lipid species as PC(+[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0188394#pone.0188394.ref002" target="_blank">2</a>]H13) 16:1–18:1. B) Positive FTMS² spectrum of protonated PC 32:0(+[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0188394#pone.0188394.ref002" target="_blank">2</a>]H6). The fragment ions identify the molecular lipid species as PC 16:0(+[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0188394#pone.0188394.ref002" target="_blank">2</a>]H3)-16:0(+[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0188394#pone.0188394.ref002" target="_blank">2</a>]H3). C) Negative FTMS² spectrum of deprotonated PI 34:1(+[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0188394#pone.0188394.ref002" target="_blank">2</a>]H6). The fragment ions identify the molecular lipid species PI(+[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0188394#pone.0188394.ref002" target="_blank">2</a>]H6) 16:0–18:1. D) Negative FTMS² spectrum of the formate adduct of Cer 44:0;4(+[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0188394#pone.0188394.ref013" target="_blank">13</a>]C2[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0188394#pone.0188394.ref015" target="_blank">15</a>]N). The annotated fragment ions identify the molecular species as Cer 18:0;3(+[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0188394#pone.0188394.ref013" target="_blank">13</a>]C2[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0188394#pone.0188394.ref015" target="_blank">15</a>]N)/26:0;1. Note that non-annotated fragment ions derive from co-isolated lipids. Fragmentation diagrams for the lipid molecules and indicated fragment ion <i>m/z</i> values are shown in <b><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0188394#pone.0188394.s008" target="_blank">S6 Fig</a></b>.</p