Molecular weight of a DNA oligonucleotide (sodium salt, pH ≥ 7):
MW = (N A x 335.2) + (N C x 311.2) + (N G x 351.2)+ (N T x 326.2) + P
where:
N X = number of residues of base x in the oligonucleotide
P = –101.0 for dephosphorylated oligonucleotides, 40.0 for phosphorylated oligonucleotides