Electrochemical Studies of β‐Carotene, all‐trans‐Retinal and all‐trans‐Retinol in Tetrahydrofuran

Abstract

Detailed electrode mechanisms involved in oxidations and reductions of all‐trans‐β‐carotene, all‐trans‐retinal, and all‐trans‐retinol have been investigated employing cyclic voltammetry, chronoamperometry, chronopotentiometry, and controlled potential coulometry at the platinum electrode in rigorously dried tetrahydrofuran (THF) solutions with tetra‐n‐butylammonium perchlorate (TBAP) as a supporting electrolyte, and the results are described. Pseudo first‐order decay rate constants of intermediate species of β‐carotene and retinal reductions are obtained and reported. β‐Carotene was oxidized to β‐apo‐12‐carotenal in the presence of water and was reduced mainly to 15,15′‐dihydro‐β‐carotene in dry THF. Retinal was reduced at various double bonds, resulting in many products including retinol, both in dry and wet THF.