Skip to main content
. Author manuscript; available in PMC: 2020 Mar 1.
Published in final edited form as: J Am Soc Mass Spectrom. 2018 Nov 12;30(3):448–458. doi: 10.1007/s13361-018-2093-9

Figure 2.

Figure 2.

LC-MS/MS chromatograms of Marfey’s derivatives of the 20 common DL-amino acids using the neutral (ammonium acetate) pH 6.5 based solvent system on a C8 column and MS/MS detection in negative mode. Each panel represents a single Q1/Q3 channel, and is associated with a particular Mar-AA. Since Leu and Ile have the same molecular weights (isobars), their Marfey’s derivatives both show up in the two Q1=382.2 panels. The Q1/Q3 = 382.2/263.2 channel is selective for Ile (two higher peaks in the Mar-Ile/Mar-Leu panel), and the Q1/Q3 = 382.2/288.2 channel is selective for Leu (two higher peaks in the Mar-Leu/Mar-Ile panel). Note that Mar-Leu/Ile also shows some signal intensity in the Mar-Asn MS/MS channel due to the Mar-Leu/Ile M+1 isotopomers, but since there is good chromatographic resolution of all these L-Mar-DL-AA species they can be individually quantified.