Use of nucleic acids in the mobile phase for the determination of ascorbic acid in foods by high-performance liquid chromatography with electrochemical detection.

The sodium salts of amino acids, nucleic acids and organic acids were examined in a new mobile phase for the determination of ascorbic acid (AA) in foods. It was possible to use disodium guanosine-5'-monophosphate (GMP) (20 mM GMP, pH 2.1) in a new mobile phase after comparison of five mobile phases. The proposed method is simple, rapid (analysis time: ca. 6 min), sensitive (detection limit: ca. 0.1 ng per injection (5 microl) at a signal-to-noise ratio of 3), highly selective and reproducible [relative standard deviation: ca. 2.7% (n=7)]. The calibration graph of AA was linear in the range of 0.1 to 50 ng per injection (5 microl). Recovery of AA was over 90% by the standard addition method.