Susceptibility of enoxaparin reducing end amino sugars to periodate oxidation.

•1,6-Anhydro-bearing tetrasaccharides were isolated from enoxaparin sample.•Their susceptibility to periodate oxidation was evaluated by NMR and LC/MS.•1,6-Anhydro-bridge is crucial for oxidation of 1,6-anhydro-N-sulfo-mannosamine.•Reducing end N-sulfate hexosamine is affected by NaIO4 under drastic conditions.•It is possible to selectively split non-sulfated iduronic acids of enoxaparin chains.