Electrochemical detection of retinoids using normal phase HPLC

Abstract Non-aqueous electrochemical (EC) detection of 13-cis-retinoic acid, all-trans retinoic, acitretin and vitamin A palmitate in non-aqueous solvents are reported. Non-aqueous (EC) detection allows for normal-phase chromato-graphy of these compounds prior to detection. The normal phase system used a mobile phase of HEX/THF/AcOH for the separation of all four compounds. The stationary phase was either silica or PVA-sil. The lipophilic salts, t-butylammoniumtetrafluoroborate or t-butyl-ammoniumhexafluorophosphate necessary for EC detection were added post-column. The limit of detection (LOD) for EC detection of these compounds is approximately 1 ng on column compared with an LOD by UV absorption of 2 ng on column. The linear detection for these compounds with the EC detector was about two orders of magnitude.