Determination of Total Antioxidant Capacity of Human Plasma from Patients with Lung Diseases Using ConstantCurrent Coulometry

Abstract

Original coulometric method for total antioxidant capacity (TAC) determination based on
the reaction of plasma antioxidants with electrogenerated bromine is developed. TAC is
expressed in units of quantity of electricity (Coulombs) spent for titration per a liter of plasma.
Coulomb is the universal unit of the TAC measurements because one can express TAC in units
of different antioxidants using Faraday constant and the number of electrons involved in the
reaction between antioxidant and electrogenerated bromine.
The TAC in the plasma being determined for patients with different types of lung
diseases is significantly lower than the one for control group. The data obtained by coulometry
correlate with results of voltammetric determination based on oxidation of plasma on the glassy
carbon electrode (Y=a + bX, where a= -6,7±0,5, b=1,07±0,04, R =0,9934).
So, the proposed method could be recommended for clinical laboratories for estimation of
antioxidant status and its subsequent correction using additional antioxidant therapy.