Mass spectrometry is an essential tool for the characterization of proteins within neuroscience. The development of faster instruments enables neuroscientists to investigate a large proportion of the proteome in the brain in only short analysis time. Yet, a detailed functional investigation of the intrinsic biochemical processes of the brain by evaluation of the post-translational modifications in proteins is still missing. Phosphorylation and N-linked glycosylation are important protein modifications within the brain as they are involved in neural development, neurotransmission, neurite extension, and synaptic plasticity. Although the importance of these protein modifications is undoubtable for the brain functionality, only a few global protein modification datasets have been generated so far in the neuroscience field. This is due to the higher difficulties to sensitively and specifically enrich these low abundant protein modifications from the high abundant nonmodified peptides and from the very lipid-rich brain material. Here, we describe how a highly selective, sensitive, low hands-on-time and cost-effective simultaneous enrichment of phosphorylated peptides, sialylated N-linked glycopeptides as well as intact sialylated N-linked glycopeptides and unmodified peptides from the same biological sample can be applied to bridge this gap in neuroscience, exemplified by a proteomic characterization of the murine brain growth spurt.