High-sensitive glycomics using seGRAP-mass spectrometry uncovers a conserved N-glycome in single human oocytes

High-sensitivity glycomic analysis is essential for advancing both basic and translational biomedical research, yet remains methodologically challenging for limited-quantity samples, primarily due to complex workflows and reliance on specialized instrumentation. Here, we introduce solution-enhanced glycan reduction and permethylation (seGRAP), a streamlined, accessible, and high-sensitive method that enables glycan profiling from sub-nanogram protein inputs and picoliter-scale human plasma using widely available mass spectrometry (MS) platforms. seGRAP-MS demonstrates consistently robust and reproducible glycomic performance and enables comprehensive N-glycome characterization of human oocytes at single-cell resolution. Our single-oocyte analysis uncovers a highly conserved N-glycome across both individuals and developmental stages, revealing a previously uncharacterized layer of molecular stability in human reproduction. By significantly lowering technical and logistical barriers, seGRAP-MS redefines the benchmark for high-sensitive glycomics, expanding accessibility and empowering broader applications in fundamental biology, clinical research, and precision medicine. Glycomic analysis of scarce material remains a major challenge, limiting insight into glycosylation in human biology and disease. Here, the authors develop seGRAP-MS, an ultrasensitive and accessible workflow enabling single-oocyte glycome profiling that reveals a conserved human oocyte N-glycome.