Mass spectrometry imaging with trapped ion mobility spectrometry (TIMS) facilitates spatially resolved chondroitin, dermatan and hyaluronan glycosaminoglycan (GAG) oligosaccharide analysis in situ.

The spatial analysis of glycosaminoglycans (GAGs) by type and sulphation state is currently unobtainable. Here, we describe a mass spectrometry imaging (MSI) approach which enables the detection, identification, localisation and profiling of GAG oligosaccharides directly from retinal tissue. With in situ treatment of tissues with relevant chondroitinase enzymes, we liberate and spatially resolve chondroitin, dermatan and hyaluronan disaccharides through to hexasaccharides directly from tissue sections. We demonstrate, through the use of trapped ion mobility spectrometry (TIMS), that it is possible to both separate and semi-quantify isomeric GAG oligosaccharide ions across histologically relevant regions. Hence, we describe the first step towards the spatially resolved analysis of multiple GAGs and their oligosaccharide sulphation state(s) in tissues.