6 chloropurine 2 deoxyriboside

Acetaldehyde and [ethyl-D₅]EtNH₃Cl were purchased from Millipore Sigma (St. Louis, MO, USA). In addition, 6-Chloropurine-2′-deoxyriboside was obtained from Carbosynth (Compton, UK). Water (LC-MS grade), methanol (MeOH, LC-MS grade), acetonitrile (ACN, LC-MS grade), 2-propanol (IPA, LC-MS grade), and formic acid (FA, 98% v/v) were purchased from Fisher Scientific (Hanover Park, IL, USA). Distilled water was purified by a Milli-Q system (Milford, MA, USA). Deoxyribonuclease I recombinant expressed by Pichia pastoris (R-DNase, 10,000 U/mg, phosphodiesterase-1 extracted from Crotalus adamanteus (PDE-1, 0.4 U/mg, recombinant alkaline phosphatase expressed by Pichia pastoris (R-ALP, 7000 U/mg, calf thymus DNA (CT-DNA, 5 mg), NaBH₃CN, Acetaldehyde, Tris base, double-filtration membrane Amicon Ultra (30 kDa cutoff, 0.5 mL), and single-filtration membrane Microcone (10 kDa cutoff, 0.5 mL) were purchased from Millipore Sigma (St. Louis, MO, USA). Silanized vials (0.3 mL, 1.2 mL, 4 mL, 20 mL) were purchased from ChromTech (Apple Valley, MN, USA). Cell lysis solution, protein precipitation solution, RNase A, and proteinase K were obtained from Qiagen (Hilden, Germany).