Determination of deoxymononucleotides and deoxynucleosides as a tool for toxicological examination--a trial for conversion of absorbance unit into molar amount in deoxydinucleotide.

Conversion of absorbance unit into molar amount was tried as to deoxydinucleotide. In order to achieve this trial, a reversed-phase high-performance liquid chromatographic method with a linear gradient mode was established for separation and quantification of deoxymononucleotides and deoxynucleosides. Selecting 2'-deoxycytidylyl-(3'-5')-thymidylic (5') acid as an example of deoxydinucleotides, this compound dissolved in water was estimated in absorbance unit at 260 nm, and it was treated by alkaline phosphatase and furthermore by snake venom phosphodiesterase. Based on quantification of the cleaved nucleic acid constituents including 2'-deoxycytidine 5'-monophosphoric acid and thymidine by the above method, the molar amount per 1.000 absorbance unit at 260 nm in the deoxydinucleotide was determined. Thus, the conversion of absorbance unit into molar amount is considered to be applicable to other deoxyoligonucleotides.