Abstract
It was reported in a previous paper that a small amount of hydroperoxide (2×10-2μeq) could be determined by potentiometry with excellent accuracy and reliability.
In the present work, the electric potential of a sample prepared for potentiometric determination of peroxide value (POV) is shown to be proportional to a logarithmic amount of hydroperoxide in a sample solution, which enables us to measure POV directly from its potential without titration.
Indeed, the calibration curve obtained for determination of hydroperoxide showed good lineality (correlation coefficient γ=0.998) from 0.25 to 10μeq of peroxide and POV determined by this calibration curve method agreed fairly well with those by potentiometric titration demonstrating the usefulness of this method.
As it is not necessary to titrate with sodium thiosulfate, this method enables the rapid determination of a small quantity of hydroperoxide appearing in a small amount of natural triglycerides, phospholipids, and also of natural lipids extracted from biological materials and food products. Especially this method is advantageous for the analysis of lipid extracts because the sample solution, which is obtained by Bligh and Dyer or Folch method, is directly subjected to this procedure without evaporation.
