Cosmetic products are chemical substances or mixtures used on the skin, hair, nails, teeth, and the mucous membranes of the oral cavity, whose use is intended to clean, protect, correct body odor, perfume, keep in good condition, or change appearance. The analysis of cosmetic ingredients is often challenging because of their huge complexity and their adulteration. Among various analytical tools, mass spectrometry (MS) has been largely used for compound detection, ingredient screening, quality control, detection of product authenticity, and health risk evaluation. This work is focused on the MS applications in detecting and quantification of some common cosmetic ingredients, i.e., preservatives, dyes, heavy metals, allergens, and bioconjugates in various matrices (leave-on or rinse-off cosmetic products). As a global view, MS-based analysis of bioconjugates is a narrow field, and LC- and GC/GC×GC-MS are widely used for the investigation of preservatives, dyes, and fragrances, while inductively coupled plasma (ICP)-MS is ideal for comprehensive analysis of heavy metals. Ambient ionization approaches and advanced separation methods (i.e., convergence chromatography (UPC²)) coupled to MS have been proven to be an excellent choice for the analysis of scented allergens. At the same time, the current paper explores the challenges of MS-based analysis for cosmetic safety studies.

Glycosphingolipids (GSLs) are a glycolipid subtype which plays vital roles in numerous biological processes, cell–cell interactions, as well as oncogenesis and ontogenesis. They are ubiquitous molecules found mostly in cell membranes. Abnormal expression of GSLs as well as altered molecular structure have been linked with progression of cancer and metastasis and are involved in the pathophysiology of neurodegenerative, autoimmune, and infectious diseases as well as inherited enzyme defects—glycosphingolipidoses. Matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) plays a leading role in analyzing and characterizing different GSLs, and thus can help to distinguish altered GSL patterns. This review offers insights into the benefits and limitations when using MALDI MS in this field of lipidomic research, with an emphasis on which are the optimal matrices in analyzing GSLs from different tissues (normal and pathological) as well as highlighting GSLs’ particular profiles in various cell cultures, and normal and pathological human tissues obtained by MALDI non-imaging MS (non-IMS). These findings can have implications in further understanding the role of altered GSL expression in various pathological conditions and could be a target for future therapies.

Glycosphingolipids (GSLs) play numerous roles in cellular processes, including cell proliferation, apoptosis, inflammation, and cell signaling. Alteration of the GSLs metabolism leads to the accumulation of particular species of GSLs, which can lead to various pathologies, including carcinogenesis and metastasis; in essence, all neoplasms are characterized by the synthesis and aberrant organization of GSLs expressed on the cell surface. Secondary brain tumors make up the majority of intracranial cancers and generally present an unfavorable prognosis. In the present work, a native GSL mixture extracted and purified from a secondary brain tumor with primary pulmonary origin was obtained through extraction and purification and analyzed by MALDI TOF mass spectrometry. Research in the field of lipidomics could offer new data for the understanding of brain tropism and metastatic pathways, by studying the glycolipid molecules involved in the process of metastasis in general and in the production of brain metastases in particular. This could shed new light on the pattern of lipid glycosylation in secondary brain tumors, with a great impact on the effectiveness of cancer therapies, which could be adapted to the specific molecular pattern of the tumor.

Surgical precision is critical in oncology, where complete tumor resection while preserving healthy tissue directly influences patient outcomes. Traditional intraoperative diagnostic tools, such as frozen-section analysis, are limited by time constraints, tissue sampling, and interpretative variability. Intraoperative mass spectrometry (MS) has recently emerged as a transformative approach, enabling rapid, label-free molecular profiling of surgical specimens in real time. Several technologies—including Rapid Evaporative Ionization Mass Spectrometry (REIMS, “iKnife”), Desorption Electrospray Ionization (DESI-MS), Matrix-Assisted Laser Desorption/Ionization (MALDI-MS) Imaging, Picosecond InfraRed Laser mass spectrometry (PIRL-MS), and novel devices such as the MasSpec Pen—offer unique strategies for intraoperative tumor characterization. Applications have been demonstrated across multiple cancer types, including brain, breast, gastrointestinal, and urogenital malignancies, where MS can improve margin assessment, tumor classification, and surgical guidance. Beyond its clinical promise, intraoperative MS faces technical and translational challenges, including high infrastructure costs, a lack of standardization, and the need for robust multicenter validation. Integration with artificial intelligence, imaging modalities, and multi-omics approaches may further enhance its clinical utility. This review summarizes current technologies, clinical applications, limitations, and future perspectives of intraoperative MS in oncology, highlighting its potential to reshape surgical oncology practice.