Procedure

1. Transfer sample (ca 0.2 mg, 1 µmol) to a 13 x 100 mm screw cap tube.
2. Hydrolyze in 0.5 mL 2M TFA at 120 °C for 30 min.
3. Evaporate the solution to dryness with a stream of compressed air, add 0.5 mL methanol and evaporate. Repeat once.
4. If the polysaccharide contains aminosugars, re-N-acetylate with 25 µL acetic anhydride for 4 h at room temperature. Evaporate with a stream of dry air.
5. Dissolve in 0.2 mL (+)-2-butanol. Add 15 µL acetyl chloride, bubble nitrogen through the solution for 30 sec., then seal the tube.
6. Butanolyze the sample for 8-16 h at 80 °C.
7. Evaporate the solution to dryness with a stream of air, add 0.5 mL methanol, then evaporate. Repeat once.
8. Acetylate with 0.2 mL acetic anhydride and 0.1 mL pyridine at 120 °C for 30 min.
9. Evaporate the solution and add 0.5 mL toluene and evaporate to dryness. Repeat once.
10. Partition between 0.5 mL H₂O and 0.5 mL EtOAc. Transfer the upper (EtOAc) phase to a new tube. Repeat the extraction twice with 0.5 mL EtOAc. Concentrate the combined EtOAc phases to dryness, dissolve in 0.2 mL EtOAc, transfer to a new sample tube and concentrate to 25-50 µL.

References

• G.J. Gerwig, J.P. Kamerling and J.F.G. Vliegenthart, Carbohydr. Res. 62 (1978) 349-357
• K. Leontein, B. Lindberg, J. Lönngren, Carbohydr. Res. 62 (1978) 359-362
• G.J. Gerwig, J.P. Kamerling and J.F.G. Vliegenthart, Carbohydr. Res. 77 (1979) 10-17