This screening service can be used qualitatively or quantitatively to determine the presence of N-glycosylation sites in complex mixtures such as cell lysates or biofluids e.g plasma and CSF. Samples are digested with trypsin and glycosylated peptides are enriched from the complex background using hydrazide chemistry. Glycosylated peptides are captured and retained on a solid support while none glycosylated proteins are washed away. PNGaseF treatment is used post-capture to release N-linked glycans from the solid support. Released peptides are analyzed by LC/MS/MS.