Abstract: In this study, factors affecting the determination of KMnO4 consumption of food contact plastics by the method of the Chinese National Standard GB/T 5009—2003 were analyzed, the main sources of measurement certainty were summarized, a procedure for certainty evaluation was established, and a relative standard uncertainty was obtained after calculating and synthesizing various uncertainty components and expanded. Potassium permanganate consumption was determined to be 2.26 mg/L for a polyethylene food box from a certain manufacturer, and the relative standard uncertainty for the determination was 0.039, and the expanded uncertainty was 0.176 mg/L (k = 2).

Key words: plastic articles, KMnO4 consumption, uncertainty