Overcoming numerous technical challenges, mass spectrometry has established itself as the gold standard technology for identifying a plethora of biological compounds originating from a single complex biological mixture. Its use in numerous clinical studies has only increased dramatically following the development of ambient ionisation sources for direct analyses such as Desorption electrospray ionization-Mass Spectrometry Imaging (DESI-MSI) combining speed and sensitivity for resolving the spatial lipid profile of a tissue sample. DESI-MSI is a technique of choice when analysing valuable and challenging-to-obtain samples, such as in the case of neurodegenerative diseases like Alzheimer's disease (AD), the most common cause of dementia in the world for which there is still no cure, as it allows to generate the spatial molecular profile of a precious sample at a high speed of analysis while preserving the sample integrity for further analyses. Moreover, many works found in the literature have emphasized the importance of the lipid profile changes around β-Amyloid plaques, a hallmark of AD, as a potential gold mine of information for understanding the disease, as well as the possibility of identifying potential biomarkers of AD. Indeed, the presence of amyloid plaques is associated with an increase in oxidative stress within their environment, potentially accelerating the loss of neurons in the hippocampus and the progression of the disease in the brain. Lipid peroxidation (LPO) has always been tied to Alzheimer's, but investigation into it has been constrained by the technical difficulties it presents. LPO has two immediate consequences: it disrupts lipid membranes and produces neurotoxic and highly reactive compounds called aldehydes, which are extremely difficult to examine using mass spectrometry...