Figure 6.

Regions of the reconstructed IMS-TOFMS 2D maps encompassing signals from low concentration peptides. The peptides were mixed with a 0.5 mg/mL depleted human blood plasma sample prior to RP fractionation. A) 1 nM [Neurotensin +3H]³⁺, detected in fraction 15, signal was encoded with a 6-bit PRS; B) 1 nM [Melittin+5H]⁵⁺, fraction 18, 6-bit encoded; C) 10 nM [Substance_P +2H]²⁺, fraction 12, 5-bit encoded; D) 1 nM [Fibrinopeptide_A +2H]²⁺, fraction 11, 4-bit encoded. Note that IMS-TOFMS signals of the spiked peptides in C and D overlap in m/z domain with those of endogenous human plasma peptides, and therefore could only be resolved and then successfully “deisotoped” due to IMS separation. All spiked peptides were detected at a mass measurement accuracy of < 5 ppm.