Figure 5. Identification of compounds to determine retention time for method generation.

Example of the retention differences between PC(34:1) and PC(34:2). Due the prevalence of ¹³C in nature, approximately 1% of the signal will carry over to higher masses (i.e., 758.6 into 759.6) and eventually overlap with the monoisotopic transition of other species. Isotopes need to be accounted for and avoided (names in red) when integrating and assigning retention times for each compound. PC–Phosphatidylcholine, SM–Sphingomyelin.