Reactions of the α‐tocopheroxyl radical in micellar solutions studied by nanosecond laser flash photolysis

Abstract

Laser flash photolysis of α-tocopherol in methanol and in aqueous micellar solutions has been shown to produce the α-tocopheroxyl radical. The reaction between the α-tocopheroxyl radical and ascorbate in positively charged hexadecyltrimethylammonium chloride (HTAC) micelles occurred with a second order rate constant of 7.2 × 10⁷ M⁻¹·s⁻¹, whereas in negatively charged sodium dodecyl sulphate (SDS) micelles the rats constant was only 3.8 × 10⁴ M⁻¹·s⁻¹. The α-tocopheroxyl radical was found to be relatively long-lived in HTAC micelles (t_½ ⩾ 5 min), allowing the slow disappearance of the α-tocopheroxyl radical by reaction with glutathione to be observed.