Glycosylation is one of the most common and complex post-translational modifications of proteins. However, there are other carbohydrates such as free oligosaccharides and glycosphingolipids-glycans that are associated with important biological and clinical roles. To analyze these molecules using liquid chromatography coupled with mass spectrometry (LC-MS), the permethylation approach was utilized. Although permethylation is a commonly utilized glycan derivatization technique, separation of permethylated glycans released from glycosphingolipid (GSL) by LC-MS has never been previously demonstrated. Here, a nanoflow porous graphitized carbon (PGC) column coupled with a high-resolution mass spectrometer was used to achieve isomeric separation of these permethylated glycans. We demonstrate the separation of free reducing end and reduced end O-glycans, free oligosaccharides derived from human milk, and GSL glycans derived from the MDA-MB-231BR cancer cell line using PGC-LC-MS.

Coral reefs are under threat from global climate change. Their decline is mainly caused by the fragility of their symbiotic relationship with dinoflagellate algae which they rely upon for their ecological success.

Glycosylation is a complex and common post-translational modification of proteins. To study glycosylation, liquid chromatography-mass spectrometry (LC-MS) is often used to profile and structurally characterize the glycans in biological systems. While bed packed reverse phase columns are frequently utilized for the separation of permethylated glycans, the use of newly commercialized micro array pillar nanoLC columns (μPAC) have not been demonstrated previously. Owing to its advantages such as low back pressure, reproducibility, and durability, we have investigated the viability of the μPAC for the analysis of permethylated glycans. In this work, we demonstrate the online purification ability of μPAC trapping column compared against PepMap trapping column. We also found that the 50 cm μPAC can be used for the analysis of both permethylated N- and O-glycans. The use of 50 cm μPAC was compared against the previous method. The use of 200 cm μPAC was also investigated for the permethylated glycan analysis. 200 cm μPAC demonstrated efficient separation of oligomannose glycan isomers as well as other complex glycans.

Cerebrospinal fluid (CSF) contains valuable biological and neurological information. However, its glycomics analysis is hampered due to the low amount of protein in the biofluid, as has been demonstrated by other glycomics studies using a substantial amount of CSF. In this work, we investigated different N-glycan sample preparation approaches to develop a more sensitive method. These methods, one with an increased amount of buffer solution during the N-glycan release step with a lower amount of sample volume and the other with Filter-Aided N-Glycan Separation (FANGS), were compared with recent work to demonstrate their effectiveness. It was demonstrated that an increased amount of buffer solution showed higher intensity in comparison to the previously published method and FANGS. This suggested that digestion efficiency during the N-glycan release step was not in an optimal condition from the previously published method, and that there is a substantial loss of sample with FANGS when preparing N-glycans from CSF.