Abstract
Used oils, 57 samples collected from homes and 11 samples from food makers in Osaka area, were examined by the new method and by the conventional methods such as A.V., CO. V., I. V., and viscosity measurement. The new method involved the separation of polar (P) from apolar (AP) fraction by thin layer chromatography, determination of the absorbance of each fraction at 233 nm by a chromatoscanner, and calculation of P/AP ratio.
The ratios have been demonstrated to increase by increasing heat treatment of oils.
The results indicated that oils from homes were generally less deteriorated than those from food makers. The new method and the determination of viscosity were found to be more effective in the evaluation of heat deteriorated oils than the determination of A. V. or CO. V. in the present cases where both thermal-and auto-oxidation were involved.
There were obtained fairly good correlations between P/AP and A. V. (<1.0) or viscosities (<80 cp), but poor correlations between P/AP and A. V. (>1.0) or CO. V.
