Chemiluminescence in the coupled oxidation of lecithin and ascorbate.

Chemiluminescence (CL) that appears during oxidation of lecithin and ascorbate has been studied. A simple system consisting only of purified lecithin, which has one double bond, and ascorbate as a physiological reductant with a low redox potential, was used. The CL spectrum of lecithin contain a strong band lying in the near infrared, and three bands at 20 900 cm-1, 17 700 cm-1 and 15 800 cm-1, being characteristic of singlet molecular oxygen (1O2). The effect of 1O2 quenchers on both autooxidation processes has also been investigated. The obtained results indicate that the main emitter is the 1O2. An addition of ascorbate to the system lecithin plus buffer causes a decrease of CL intensity. That is a result of stronger quenching properties of ascorbate and not due to efficiency of the generation of 1O2.