Cathodic stripping analysis of DNA/RNA bases in nonaqueous media

The methods for the determination of nucleic acid bases by differential pulse cathodic stripping voltammetry in dimethyl sulfoxide are proposed and developed. One method uses mercury drop or film electrodes. The required anion is produced by the deprotonation of the parent molecule by added tetrabutyl‐ammonium hydroxide (TBAOH). Optimization of the method is discussed. The effects of deposition potential or time, scan rate, pulse height, TBAOH concentration, and other experimental parameters are examined. Included are the results of the determinations of thymine, uracil, cytosine, adenine, and guanine. The second method uses a mercury‐film rotating ring‐disk electrode. The anion, produced electrochemically at the disk held at a negative potential, is swept to the ring and deposited at a suitable, more positive potential. Detection limis for nucleic acid bases are 10−8 to 10−9 M.