The investigation of the elution tests of the fluorescent whitening agents contained in the paper packing container for foodstuffs

Abstract

We requested some analytical organizations to carry out the fluorescent whitening agents examination of the papers. which have possibility to contact with foodstuffs directly. Although the examination was performed based on the official standard method, Kansyoku No.244, there was a considerable difference in the results obtained from the examinations carried out by various organizations. Kansyoku No.244 examination is performed as follows. First, the specimen is extracted with weak alkali water. Then, the pH value of extract is adjusted between pH 3 and pH 5 with diluted HCl solution, and the gauze is dipped in the above extract. Finally, the gauze is observed under UV lamp to judge whether fluorescent whitening agents are extracted or not. In this investigation, it was found that the fluorescent whitening agents efficiently stained the gauze in strong acid water, but were little in weak acid and alkali water and the observer's abilities of recognizing the fluorescence was difference, respectively. The different results of the examinations carried by the analytical organizations were caused by the difference in pH, at which the gauze was dipped in the extract, and the observer's ability of the recognition of the fluorescence.