Photochemiluminescent detection of antiradical activity; III: A simple assay of ascorbate in blood plasma.

A simple procedure to determine the ascorbate in blood plasma was elaborated based on a temporary inhibition of the photo-induced, O(-.)2-mediated, chemiluminescence emanating from oxidation of luminol. To remove the interferences, mainly from urate, a simple enzyme-free one-step method for plasma sample preparation by means of a gel filtration was combined with the photochemiluminescent investigation of the eluate. The results of the photochemiluminescent assay of ascorbate coincide well (r = 0.994) with a photometric method with ascorbate oxidase. The mean value of ascorbate in human blood plasma, obtained from 37 healthy volunteers, was 59.6 +/- 25.8 mumol/l. Patients with atherosclerosis having a myocardial infarction in their anamnesis displayed significantly lower values: 27.2 +/- 12.8 mumol/l (n = 32), P < 0.001.