1. Dissolve 100ug DNA in 200ul distilled water.

2. Add MgCL₂ and sodium acetate to the final concentration of 15mM and 10mM, respectively.

3. Incubate with 2 units DNAse I at room temperature for 15 minutes.

4. Add ammonium bicarbonate to the final concentration of 100mM, and then incubate with 2mU            phosphodiesterase at 37oC in water bath for 2 hours.

5. Add 1 unit of alkaline phosphatase and incubated at 37oC water bath for another 1 hour.

6. Air dry the solution with degraded DNA. Derivalize produced deoxyribose to its aldonitrile

acetate form as usual for analysis on GC/MS spectrometer.