A simple method based on hydrophilic liquid chromatography (HILIC) and electrospray mass spectrometry (ESI-MS) for the detection of monoethanolamine (MEA) degradation products in CO2 postcombustion capture plants has been developed. MEA byproducts determination has traditionally been difficult due to analytical separation problems. Even in recent sophisticated methods, this difficulty remains as the major issue often resulting in time-consuming sample preparations. In this work, we have collected samples directly from a real pilot plant and analyzed them, for the first time, by using matrix assisted laser desorption ionization (MALDO-MS or ESI-MS without any separation, both in positive and negative ionization modes. Alternatively, a previous liquid chromatography (LC) run was performed before ESI-MS; traditional reverse phase separation and HILIC were compared. Our results indicated that HILIC separation using an amino modified column, coupled to ESI-MS or ESI-MS/MS measurements, is the suitable method for identifying as many degradation products. Moreover, some plausible degradation mechanisms are proposed to explain some peaks in the spectra. The present work is intended as a preliminary study aiming to show the usefulness of these alternative techniques for this kind of investigations.