Are nucleotides in solution more stable than its lyophilised form?
Yes. Preparations of dNTPs decompose into nucleoside di- and mono- phosphates via a disproportionation reaction. At temperatures above 4°C, lyophilised preparations of deoxynucleotides undergo disproportionation faster than nucleotides in solution. In contrast, at -20°C, the rate of degradation for both forms is less than 1% per year. Nucleotides in solution are also generally purer. Some lyophilised preparations approach 98% purity or more but rarely match the >99% achieved by extremely pure solutions. Generally, solution nucleotides are purer than the lyophilised version.